Chris Porter's GeoMetron G1
Editorial & Podcast

Pitching Forward: The Impact of Steep Seat Tubes

Words A.J. Barlas
Photos A.J. Barlas (Title Image Alex Luise)
Date Mar 29, 2021
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Want to hear more of the conversation between A.J. and coach, Joel Harwood? Listen to the full discussion below, in the latest podcast.

Steeper seat tube angles have worked wonderfully for some riders but no two people are alike. For all of us happily spinning the cranks from a more forward and upright seated position, there’s a heap who don’t get on with it. It's possible the seat tube angle isn't actually the issue though.

I’m a rider who’s been overwhelmingly happy with a steeper STA. Every time it pitches further forward I find myself more comfortable, better able to access power with a quieter upper body and less focus needed to keep the front wheel planted. Bikes with shallower seat tube angles always resulted in a need to ‘hump’ the bike up climbs, causing all sorts of aggravation in my back. My position on the saddle also needed to shift around constantly to keep the front of the bike appropriately weighted.

For others, a steeper STA isn't as simple. I’ve heard from riders dealing with discomfort in their knees, sit bones, hands, or simply feeling like they don’t have the power they’re used to. When I first heard about these issues, I began researching the pros and cons of steeper seat tubes. During my research, I began steering away from opinions and found myself going down the rabbit hole of scientific research .

ncbi-seat-angle-study.jpg

What bikes look like in scientific drawings. I don't know about you, but my efforts to draw a bike aren't much better and I swear that seat is from one of my own sketches.

What the Science (Currently) Says

As I read more studies, I saw a common theme unfolding; steeper seat tube angles improve pedalling efficiency although exactly how our muscles are being recruited to cause the improvements isn't completely agreed upon. With many studies suggesting increased efficiency and power output during the downstroke, it’s hard to disagree with steeper seat tube angles improving our effort on the bike.

The science seems a bit lop-sided though, and while there are conflicts regarding muscle recruitment, the studies I read largely swing in favour of steeper is better. This led me to seek research specifically on shallower seat tube angles. Unfortunately, this was far more difficult to source, despite research read dating as far back as the early nineties.

All the studies were also specific to road, triathlon and track bikes; research specific to mountain bikes is as common as unicorns. I did, however, find a study abstract discussing the merit of shallower seat tube angles that wasn’t road bike specific. It focused on "pedalling a bicycle in daily life on public roads," and found that with the seat slightly lower than ‘optimal,' a shallower angle was beneficial.

steep-seat-tube-angle-mtb-nsmb-210321-ajbarlas-00911-2

Surprisingly, my wife's bike measures within ~5mm from the center of seat mast at seat height to center of bar to my own bike. Clearly her size medium Evil Following is too small for me despite the cockpit measurements being almost the same. Her seat post is ~72.5 degrees (low position) and my bike is currently ~78 degrees

Lessons from a Coach with an Exercise Physiology Education

With much of the research focusing on steeper angles and this or that muscle, I asked a friend, and founder of Blueprint Athlete Development, Joel Harwood for his thoughts. Joel studied exercise physiology and combined with his coaching experience, was able to offer more insight. It did little to provide an argument for shallower STA angles but there was much to take from the discussion.

Coach Harwood's personal experience reflects my own; steeper has been better, despite our very different physiques. But his coaching and science background brought up the topic of rider technique and position on the bike. He mentioned the more upright seated stance granted by steeper STAs allows us to better activate the posterior chain, increasing the involvement of muscles like the glutes and hamstrings. Our bodies don't like being in the hunched position created from shallow seat angles for extended periods, in part because the posterior chain isn't able to be as active as it should.

steep-seat-tube-angle-mtb-nsmb-210321-ajbarlas-00911.jpg

Before taking these photos, I had no idea what my seated position was like. It's more upright than I thought and I'm the most comfortable I've been on any bike.

steep-seat-tube-angle-mtb-nsmb-210321-ajbarlas-00941.jpg

My extra large Turbo Levo doesn't fit as well as the G1. It's clear to see that my upper body is tilted forward more and it causes some discomfort when riding.


Body position might be more important than the actual geometry numbers – Coach Joel Harwood

Joel's also found that rider discomfort for some people with steeper seat tube angles can come from the body being too familiar with their previous position on the bike. Our body will adapt over time and certain muscles can see less activity as a result. He noted muscles used minimally in a regularly practiced activity can result in those connections being turned off, making it harder to adjust to a new position.

When Joel brought up the common issue of glutes not firing properly, particularly after a knee injury, it struck a personal chord. Many years ago, my coach and a physiotherapist discovered this very issue after I had knee surgery. Since then I’ve worked hard to keep my glutes active and strong but never considered how the geometry of my older trail bikes may have contributed to my problems.

steep-seat-tube-angle-mtb-nsmb-210321-ajbarlas-00914.jpg

Edit: Adding these after the article originally went live. A commenter pointed out below, climbing position on an MTB is more important than on flat ground, and I agree. Note the center of mass is at, or ahead of, the drive-side pedal on the ~78-degree STA G1 when the front wheel is on a milk crate.

steep-seat-tube-angle-mtb-nsmb-210321-ajbarlas-00928.jpg

On the Evil, my C.O.M. looks to be behind the drive-side pedal. These seem minor but have a large impact and while I was doing this on the milk crate, I had to tilt my torso forward to compensate for the slack STA and prevent tipping back. This despite the Evil being over sprung for my weight

While the studies are leaning towards Joel's experiences, both personally and with athletes he works with, he made sure to note they are conducted in very controlled environments, which don't align well with mountain biking. He's found the results can be skewed if the goal is to prove something specific. While overall, Joel agrees with the findings, particularly when it comes to mountain bikes, he feels they should be taken with a grain of salt.

On the trails, Coach Harwood believes the rider has more influence than any single number or the overall shape of their bike. But having a bike that provides a strong base for more efficient pedalling is important, which he feels a steeper seat tube angle offers. Of course, you need to weight pros and cons, but having a strong starting point is only going to benefit riders.

steep-seat-tube-angle-mtb-nsmb-210321-ajbarlas-00921.jpg

My wife's Evil Following V1 leans more toward the historical influence of road bikes on MTB than it does push toward the numbers seen on bikes released in the last few years.

A Little History

How much influence do the UCI's regulations have on the geometry of enthusiast-level bikes? Surprisingly, it may be more than I suspected. Just as their regulation requiring the same size front and rear wheel delayed the move to mix-wheeled downhill race bikes, their rules for frame geometry may also be holding back new developments in road cycling.

The UCI's restrictions are good for some safety purposes but their limit on geometry may be holding things back. The seat tube is somewhat stuck where it is when it comes to road bikes because the nose of the saddle needs to be a minimum of 5cm behind a vertical line through the centre of the bottom bracket. [UCI Technical Regulation Clarification Guide, article 1.3.013] There are also limitations on wheelbase, the relationship between the handlebar and front axle, and heaps more. These rules are specific to road bikes used in competition but the technology and discoveries made at the elite level trickle down to the shop floor of the local bike store.

Screen Shot 2021-03-23 at 12.57.12 PM.png

The graphic used in the UCI tech guide where discussing geometry.

We don't need to dive too deeply into road bikes, but they're relevant here because of their past influence, and much of the research I’ve read is specific to them. Studies suggest a steeper STA provides greater efficiency, yet the UCI’s rules prevent bikes from deviating too much from current measurements. Triathletes, whose bikes are governed by different rules, have also been studied to show a benefit from steeper seat tube angles both on their bike and when transitioning to the run. Unfortunately, I’ve not found any studies specific to mountain bikes.

As mountain bikes have evolved, the historical influence of road bikes has faded and in the last few years, we’ve seen a drastic shift. Our mountain bikes have steadily grown in length, particularly the front centre, and our seat tube angles have steepened. I’m not sure which is the chicken or the egg, but the pitching forward of seat tubes has coincided with front centre growth.

The research has made me curious; what would happen to road bikes if the rules were more flexible? Maybe we'd see longer wheelbases and top tube measurements with shorter stems and steeper seat tube angles? Or maybe we'd see more riders suffering injuries? I’m no bike fit guy, so maybe there are limitations caused by fit? If there are, why don’t those apply to track or triathlon bikes? That's another discussion altogether..

norco-sight-230120-ajbarlas-07836.jpg

The Norco Sight pushed the brand's thoughts on bike geometry into new territory and has been popular with consumers.

Steeper Seat Tube Angles For The Masses

What does this research suggest for riders uncomfortable with steeper seat angles? It could be that patience is needed to give your muscles and nervous system time to adjust to the change. With riders coming in all shapes and sizes, it's not that simple but for many riders adaptation is possible.

We don't know where the upper limit is yet but it's possible some of the bikes available already go a bit too far for the majority. Everybody is different and not everyone will get along with the extremes, wherever those are. But in all of the research, done on road bikes, steeper seat angles saw performance benefits. That appears to transfer to our beloved mountain bikes as well.

Thankfully, the UCI doesn't restrict trail bike technology and manufacturers can try anything they dream up. Heaps of testing and research has been conducted by the very smart people who develop the bikes we ride as well. I'm stoked to see the path continue to be forged toward more specific bike shapes for riding in the mountains but there’s much to learn and consider as bikes evolve. Best to keep an open mind and be aware of the limitations we may have as individuals, and when possible, recognize that we may need to adjust for those.

AJ_Barlas
AJ Barlas

Age: 39
Height: 191cm/6’3"
Weight: 73kg/160lbs
Ape Index: 1.037
Inseam: 32”
Trail on Repeat: Changes as often as my mood.
Current Regular: Every test product spends time on Entrail

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Comments

cerealkilla_
0
jdt  - March 28, 2021, 9:52 p.m.

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cyclotoine
+1 Pete Roggeman
cyclotoine  - March 28, 2021, 10:34 p.m.

Thanks for the read. I’ve been eulogizing steep seat tubes for a few years now. Mine still isn’t steep enough. I’m also about the same height as you, maybe 192 cm abs have always gotten zero offset posts and slammed the saddle forward. Including my road bike which looks awful but feels better. When I built my own monster cross bike in 2013 I gave it a 74 degree seat tube which was considered steep for that kind of bike. I only wish I did 75 and also a long front center. I have a bike on order with a 78 (privateer 141) so I’ll see how that does compared to my current 76 ish effective.

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AJ_Barlas
0
AJ Barlas  - March 29, 2021, 7:04 a.m.

78 degrees is quite comfortable and where I am currently perched. I’m envious of your new short trail rig, that’s going to be a heap of fun! I reckon you’ll quite enjoy the steeper STA.

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cyclotoine
0
cyclotoine  - March 28, 2021, 10:34 p.m.

This comment has been removed.

xy9ine
+2 Cr4w Pete Roggeman
Perry Schebel  - March 28, 2021, 10:38 p.m.

i :heart: my current 78.6* sta. so many years, climbing uncomfortably perched on the noses of saddles. amazing it's taken so long to figure this out. granted, reach had to stretch a few inches as well to make this work (which, again, i have no idea why no one had at least attempted years ago). hindsight, etc. 

also - aj, looks like you're a prime candidate for an aenomaly switchgrade saddle tilt gizmo.

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AJ_Barlas
0
AJ Barlas  - March 29, 2021, 7:01 a.m.

Mate, I hear ya. I was stuck doing the same thing for too long. 

They intrigue me but I don’t believe it’s necessary. With the long 210mm OneUp dropper, my seat is so far away the angle of the seat hasn’t been a problem. Also, the title image is Chris Porter’s G1, not mine. My seat is only just tilted down and post extended it’s close to level.

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xy9ine
+1 AJ Barlas
Perry Schebel  - March 29, 2021, 9:38 a.m.

ahh, missed that wasn't your bike (should have noticed the fork). also should have added the footnote: *for aesthetic purposes, primarily. 

also - stoked about the CP podcast. love hearing his ruminations.

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BertBC
0
Albert Steward  - March 30, 2021, 1:50 a.m.

On the saddle angle topic I always figured the Specialized WU dropper would make much more sense setup to give a slightly nose down climbing position at full extension (and a flat position when down rather than nose up)

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Varaxis
+4 demo7_rider AJ Barlas Cr4w roil
Dan V  - March 28, 2021, 11:21 p.m.

There's a correlation between short WB and slack effective STA. 

Should measure the horizontal distance the saddle is behind the BB to calculate the effective STA. Some TT bikes have multiple seat positions, forward for aero bars and rear for normal road.

I suspect some prefer slack STA 'cause they have a large fitness base from training on slack STA, which doesn't fully transfer over to a steep STA position. Neglected muscle groups being recruited due to the new position makes them feel weak too.

I say F incremental STA steepening. I've tried 83° on my Grim Donut experiment. I believe that there's room for it to get that steep. My sitting position being similar to my standing position was a bonus, as well as having similar susp sag for both standing and sitting.

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AJ_Barlas
+1 Cr4w
AJ Barlas  - March 29, 2021, 6:57 a.m.

“I suspect some prefer slack STA 'cause they have a large fitness base from training on slack STA, which doesn't fully transfer over to a steep STA position. Neglected muscle groups being recruited due to the new position makes them feel weak too.”

This is what I’m leaning toward after discussing the topic with Coach Harwood. I’ve also had similar issues away from the bike. We are creatures of habit.

Do you think the correlation between shallow STA and short wheelbases is anything more than that?

Reply

craw
+2 Pete Roggeman jaydubmah
Cr4w  - March 29, 2021, 7:45 a.m.

These new long WB, steep ESTA, slack HTA bikes also require a different approach to riding them aggressively. I've seen a few riders go back to less aggressive geo because they couldn't adapt to how forward you have to ride them downhill. My XL G1 corners really well but you have to basically jump forward downhill over the bars for it to work. Some bikes need to be piloted a certain way and some people can't quite make the change.

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AJ_Barlas
+3 Pete Roggeman Cr4w Tjaard Breeuwer
AJ Barlas  - March 29, 2021, 8:59 a.m.

For sure, changes to the shape of a bike require changes to ride it, at least mentally. Being more centred on the bike can make it easier to ride well than a shorter bike though, especially for taller folks that have had ill-fitting bikes for so long. But as Joel mentioned with steep STA, the body needs some time to adapt to a different bike, that doesn't necessarily make it a bad thing, it's just different. 

I ended up settling on a steeper HTA on the G1 to allow for easier weighting of the front wheel. I did it a number of different ways and depending on whether mix-wheeled (currently) or 29, my setup alters a bit. But both allow me to effortlessly weight the front. I was happy with the 62.5-degree HTA of the G16 but it was 15mm shorter reach. The same HTA on the larger size positions the front wheel a long way out and I've adjusted the geo to suit. But that's because I've been able to. Front centre has heaps more to do with things than HTA numbers on a chart. (I wish more manufacturers would include front-centre and "spread" in their charts. They're both important measurements IME).  

Some of the newer bikes w/ longer front centres but not adequately longer rear centres create an issue with weighting the front. The front end gets too far ahead but the rider is trying to ride as they always have, and the short rear centre allows this more. A longer rear naturally forces the weight forward. A stiffer rear suspension can also do it but depending on the bike, this can create issues with grip and necessitates the fork being set up appropriately to compensate, which often puts the rider back again. Then there are individual preferences, body shapes, terrain, the list goes on. 

It's a balancing act and there's much to learn when moving to the newer shapes of our bikes. But as you point out, what works for some won't for others.

Reply

tehllama42
+2 AJ Barlas Cr4w
Tehllama42  - March 29, 2021, 4:20 p.m.

Cr4W, I think you're spot on with that, but the trade really comes down to which outcome is worse - going OTB, or losing traction on the front?
For my part, I'm so much happier with the former being the case that I'll live with some downsides, and practically adapting over to it has come over time, to the point where I ride in a position that I know would sent me beyond the front wheel on other bikes in the same terrain, so it is a serious learning curve to get that right.  A bit part of that is also how improved forks are, and no longer have to be tuned in a way that chooses traction or packing upwards with successive hits.

Reply

Varaxis
0
Dan V  - March 28, 2021, 11:21 p.m.

This comment has been removed.

fartymarty
+1 Tjaard Breeuwer
fartymarty  - March 29, 2021, 1:47 a.m.

AJ - What does you "butt to bar" measure on your G1 at your pedalling seat height?  (centre of seat to centre of bars).

As a back ground my L Krampus (~73ish) and XL Murmur (~76) have a similar butt to bar despite the 75mm reach difference. As such I feel like I am in a similar position on both bikes albeit further forward on the Murmur. The Murmur climbs steep much better as you aren't perched on the nose of the saddle however the Krampus is more comfortable on the flats as you have less weight on your hands. I've only been on the M for 2 year so i'm probably still adjusting to the newer geo. Interestingly both bikes have a similar CS length 446K v 445M.

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AJ_Barlas
0
AJ Barlas  - March 29, 2021, 6:53 a.m.

I’m not sure but the seat on my G1 is the closest to centred on the rails that I’ve ever been (I still push it forward ever-so-slightly). Every other bike I’ve, the Turbo and my wife’s Evil, has the seat slammed or closed to slammed forward in the rails, to move my/our butts away from the rear hub and provide a more upright, relaxed position. 

I found with all of my previous bikes (pre-G16) I would spend about 90% of my rides at the front, or right on the tip of the saddle, despite the slammed seat rails. I kinda wish I still had one of them to compare against, or that I kept a journal of all my measurements and settings back then.

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hongeorge
+1 AJ Barlas
hongeorge  - March 29, 2021, 2 a.m.

I think droppers have gone a long way towards making steep seat tubes possible - and maybe a factor in why road bikes don't favour them - when the saddle gets moved forwards, it can end up in a place that's much less suited to out-of-the-saddle climbing. No issue for me, i drop the saddle out of the way, but for a roadie attacking a climb it's a different story.

Reply

HitechTurtleneck
+2 AJ Barlas Andy Eunson
HitechTurtleneck  - March 29, 2021, 5:45 a.m.

I think road bike geo, especially the small-as-possible wheelbase + long/low stem, is most in the service of peloton  aerodynamics.  Non-race riders would definitely benefit from ‘relaxed’ geometry for the drop-bar bikes they ride on the road, and the gravel segment seems to be filling that need.  But for a team racing other teams all looking for advantage a leadout train that’s just a little tighter is just a little more aero, and their sprinter gets launched a little fresher- so everyone’s bike evolves to a tiny wheelbase. 

I don’t race, but I ride a drop-bar with a dropper-post because I’ll never have bike without a dropper-post.

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AJ_Barlas
0
AJ Barlas  - March 29, 2021, 6:43 a.m.

That’s a really good point, Hitech. But how does a shorter wheelbase/longer stem improve aerodynamics to a longer wheelbase, longer top tube and shorter stem (giving the same hand position)? Even with no change in seated position in relation to the bottom bracket and the hands remaining in the same spot, I don’t see the need for short wheelbases on the road. 

Sure, cross winds may be more of a hassle but in many situations wouldn’t the stability at speed outweigh that con? Maybe the longer wheelbase negatively effects drafting efforts?

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olaa
+1 AJ Barlas
olaa  - March 29, 2021, 8:21 a.m.

Yup, with shorter wheelbase you can get closer to the rider in front. At high speed every cm makes a difference! Also in a peleton it's nice to have a shorter bike meaning less wheel overlap, and thus less risk of a crash when people move sideways.

All that said, now that i have given up serious racing i'm on a far bigger frame with shorter stem. So much nicer for all other use than pure racing :)

Reply

olaa
0
olaa  - March 29, 2021, 8:21 a.m.

This comment has been removed.

HitechTurtleneck
+2 AJ Barlas Pete Roggeman
HitechTurtleneck  - March 29, 2021, 8:57 a.m.

It’s all about the race group and erasing everyone else’s advantages.  The vast overwhelming majority of aero resistance is the rider’s body.  The closer rider A can get her body to rider B’s body, the more tow. 

But nobody reading this will ever need to look for the tiny advantages that road Race teams need to.  Road race bikes are highly evolved for what they are and how they’re used.  It’s just that using what’s good for World Tour road racing as good for bikes is totally wrong.  Especially when it comes to singletrack, but in general too.  Drop bars and smooth(ish) fast surface is super fun,  but “civilians” are way better off with fender and big tire clearance, longer chainstays for stability and, potentially comfort. Longer reach, slack head angles, and shorter stems work great on dropbar bikes- but their seat angles won’t get much steeper because that angle works pretty good for rolling flat.  TT/tri-bikes have steeper angles but are also meant to be ridden almost exclusively in the tuck+aero bars, on courses that aren’t very dynamic and surfaces that are super smooth.  A great TTer’s upper body doesn’t move at all, and a mountain biker’s upper body, while it should be calm, is upright, open, and moving the bike around constantly.

Mountain bikes and bikes for non-racers don’t need/shouldn’t have short wheelbases*.

*except for BMX, slope-style, mini-velo, fixie-cross, and wall-o-deathcycles...

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Varaxis
+1 hongeorge
Dan V  - March 29, 2021, 1:54 p.m.

I noticed this too on my Grim Donut experiment (83° STA). Since the saddle is more forward and higher up:

- could bump into the saddle when hammering out of the saddle on flat ground. Not a problem on a climb.

- couldn't stand in front of the saddle at a stop sign/light, and also have a foot on the pedal.

- a bit more inconvenient to mount the bike. I would rely on using the pedal to get on the bike, rather than mount in one fluid movement like a CX racer would.

A dropper post remedied all these issues. It's a must, preferably with enough travel to allow the rider to place feet on the ground while still sitting on the saddle.

Reply

fartymarty
+1 Pete Roggeman
fartymarty  - March 29, 2021, 4:43 a.m.

AJ - Sounds like you need to get the Godfather of Modern MTB Geometry (Mr Porter) on a podcast for his take on it.  I'm sure there is scope to extend this article into a series of discussion pieces on modern geometry.

Reply

AJ_Barlas
+4 Cr4w Pete Roggeman Noel Dolotallas hongeorge
AJ Barlas  - March 29, 2021, 6:35 a.m.

Chris and I have been discussing this for years. I’m just finally getting happy with remote recording quality (audio can be a challenge), so it will happen soon.

Reply

fartymarty
0
fartymarty  - March 29, 2021, 10:51 p.m.

I'm looking forward to it.

Reply

Vikb
+3 Andrew Major goose8 Michael
Vik Banerjee  - March 29, 2021, 6:17 a.m.

I'm not a particular fan of the steep STA. I haven't found any performance benefit personally. On longer rides I find being pushed forward towards the bars less comfortable then a less steep STA. I've got droppers with 1" setback heads now so I can adjust my saddle position rearward a bit and that helps. There are bikes now with STAs so steep I don't bother even thinking about them as options.

I'm 5'11" with a 33" pants inseam so not particularly unusual body shape.

I've always wanted a steel FS bike so I may go that route at some point so I can get a custom STA depending how things progress towards 90 degrees!

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AJ_Barlas
0
AJ Barlas  - March 29, 2021, 6:37 a.m.

Vik, how long have you been mountain biking, and cycling for? How has your bike setup evolved with the more modern bike shapes?

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Saidrick
+1 Michael
Saidrick  - March 31, 2021, 10:42 a.m.

I would agree, what ever benefits you get from a steep seat  tube on the climbs,  turn into negatives if you live somewhere with a lot of flat or rolling terrain. I am also not a fan of the longer slacker lower bike tech. Pedal strikes and a front wheel washing out all the time is no fun. 

Good article, but I think a  focus on the greater rider environment  and not just north shore, that’s straight up and straight down, would be helpful for the rest of us that ride in different areas. . For shore riders, steep seat tubes and long ,low, slack make a lot of sense, other places not so much.

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goose8
+1 Michael
goose8  - April 1, 2021, 10:31 a.m.

I'm with Vik- steeper ST angles don't do much for me. I've had some injuries over the years (e.g. torn labrum in hip) and have recently (re)discovered that there's a fairly limited range of body positions that work for me. Both my bikes have slacker ST angles to begin with and I run offset dropper posts to get a position that works for me.

I enjoyed reading this piece though- thanks for putting together such a thoughtful conversation on the topic!

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slyfink
+1 Lu Kz
slyfink  - March 29, 2021, 7:28 a.m.

Do you think we could get some of the benefit of steeper HTA by shortening our cranks? When I looked at the GIF of you on the Evil vs the Geometron, it seems like you were pitched forward on the bigger bike. But a closer look at your knees show it dropping dramatically on the larger bike. 

I have a 75° STA, and 175mm cranks. I also have very short legs (28.5" inseam). I've been toying with the idea of shorter cranks, mostly for reduced pedal strikes, but I wonder if some of the benefits of a steeper STA might accrue as well?

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AJ_Barlas
0
AJ Barlas  - March 29, 2021, 9:20 a.m.

I've stared at that gif for far too long and you just sent me down the path again, haha. I believe the change in my legs is more to do with the position of my C.O.M. in relation to the pedals. The cranks on my bike are shorter than the Evil—the G1 is 165mm and the Evil I believe is 175. 

I'm definitely pitched further forward, which is the point. More upright so that when the trail goes up, I'm in a better position to climb. Lee (of Lee Likes Bikes) had an interesting article or two several years back about shorter cranks. I don't remember his final findings if there were any, but I don't have an issue with the shorter cranks on this low BB bike. But I've been riding 165 cranks for years now and am used to it.

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moraucf
+2 AJ Barlas Noel Dolotallas
moraucf  - March 29, 2021, 3:21 p.m.

As a fellow short inseam rider, I can highly recommend you give shorter cranks a shot. I do think it gives you some of the benefits of steeper STA. Am currently on 165mm and could probably go shorter.

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craw
+4 AJ Barlas Pete Roggeman jaydubmah LWK
Cr4w  - March 29, 2021, 7:42 a.m.

> Our body will adapt over time and certain muscles can see less activity as a result. He noted muscles used minimally in a regularly practiced activity can result in those connections being turned off, making it harder to adjust to a new position.

This totally squares with my experience with buddies who are decidedly from the 'I get all the fitness I need on the bike' camp versus those who also have a broader intake of strength, training and mobility work. My friends in the former category aren't aging well and are quitting the sport one at a time or are watching their worlds shrink as they fail to properly manage small-but-significant injuries. The ones in the latter are generally fitter and adapting to new physical challenges better.

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AJ_Barlas
+1 Pete Roggeman
AJ Barlas  - March 29, 2021, 9:06 a.m.

It's true. A well-rounded level of fitness will more easily adapt at the very least. I've heard Coach Harwood talk many times with his athletes about being 'athletes,' and not just cyclists. He wants them to do other things to help in their competitive success on the bike. I haven't discussed it at length with him but I can see him thinking along the lines of a better balance of fitness helping many aspects when competing on the bike, injury prevention and coordination. Not to mention it helps prevent burning out.

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craw
+3 jaydubmah AJ Barlas LWK
Cr4w  - March 29, 2021, 11:06 a.m.

If you're doing lots of other activities and training to stay well-rounded then changes to your position on the bike don't seem like such a big deal since your patterns are working broadly.  Cycling is such an unbalanced activity it makes sense to do more stuff just to offset that (spinning little circles, leaning on flexed wrists for hours, terrible posture, etc).

Life gets a lot better when you go riding to express fitness rather than create it.

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rigidjunkie
+3 AJ Barlas Deniz Merdano Noel Dolotallas
Allen Lloyd  - March 29, 2021, 7:54 a.m.

I think a part that is missing from this is suspension design.  Some designs benefit greatly from a steeper seat tube angle and others are negatively impacted.  If your suspension sucks down when you climb a steeper angle helps, if your bike firms up it doesn't help.  

The part about muscle memory is HUGE, I rode my wife's bike (which has a steeper STA) and found my legs were sore in odd places the next day.  Oddly I also felt like her bike was a rocket ship climbing, it felt like I was creating way more power than normal.  Riding flat and down hill her bike feels like complete dog poo to me.  I ride a 1st gen Hightower and my wife has a 4th gen 5010.  The jury is still out on if it is the geo or the smaller wheels that make me dislike the 5010 so much.

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AJ_Barlas
0
AJ Barlas  - March 30, 2021, 6:44 a.m.

Great point on suspension design. We really need studies on these items that are focused on MTB. It would be quite interesting to see what the labs discover for our bikes.

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roil
+2 Andy Eunson Cr4w
roil  - March 29, 2021, 8:29 a.m.

Road bike STA is optimized for riding on flat land. MTB STA should be optimized for climbing (and have a steeper STA). 

All of the seat position photos above only show the rider on flat land. Seating position should factor in uphill grade and the argument could be made that attack position should factor in downhill grade.

I would rather prioritize performance and comfort when climbing where effort is higher vs flat land. There is a great youtube video on this. Just turn on the captions unless you speak italian.

https://www.youtube.com/watch?v=j-r2k7527vA&t=9s

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AJ_Barlas
+2 roil Cr4w
AJ Barlas  - March 29, 2021, 9:12 a.m.

Right so why, then, do triathletes benefit from the steep STA while on the bike? The research suggests road bikes could be steeper and see improved efficiency. Are the aerodynamics of a tri bike much worse than a road bike?

Here are some pics of the bike with the front wheel raised. I'll try to find a spot for them above in the article.

G1 climbing a milk crate

Evil Following climbing a milk crate.

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roil
+2 Cr4w Morgan Heater
roil  - March 29, 2021, 10:59 a.m.

The milk crate pics are great! Apologies if they were there all the time, and you're just humoring me. 

Regarding tri bikes and a steep seat tube being better, I think the kinetic chain reasoning makes sense and taking that idea even further, the position of the hips relative to the bottom bracket or centerline of the cranks needs further examination.    

The sprint position on a road bike or standing position when climbing any bike has your hips directly over the bottom bracket. Granted, you are no longer seated so there are other factors at play. However, this vertical hip and bb alignment also allows gravity to work in our favor, sitting or standing. 

Our bodies are designed for walking and running so it would make sense that our muscles are strongest at or near this vertical position as this is when the body's muscles experience the largest loads (initial ground contact).

 

Bottom line, MTBs geo needs to be completely reevaluated for its actual use case (seated climb and standing descent) as opposed to slowly tweaking flat road bike geo.

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jason
+2 roil taprider
jason  - March 29, 2021, 11:16 a.m.

Exactly.  MTB adopted road bike geometry (think 73 seat and 71 head tube back in the day ), from road biking.  This did not take into account the sometimes much steeper climbs and associated effect on the seat tube angle.  

Also, at the time there was no rear suspension sag to impact the seat tube angle (which is magnified by climbing). 

Current designs are starting to do that but what is likely needed is a seat tube angle with sag on flat land, as well as a seat tube angle with sag while climbing (industry adopted number so every manufacture uses the same metric), to be part of the geometry table. Then design the bike to hit the proper angle with sag and sag plus climbing.

Seat tube angle unweighted on a full suspension bike is irrelevant.

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tehllama42
0
Tehllama42  - March 29, 2021, 4:24 p.m.

Yeah, I think the honestly largest improvements with steeper STA's has been that the ESTA while climbing under realistic suspension loads is finally back somewhere close to the same 73° that works elsewhere, and suddenly making our horribly inefficient 0.25hp meat-servo propulsion work that bit more efficiently transforms how well we can do technical climbing.  Probably also why dual-link setups with intrusively high anti-squat values are also so popular, those don't make the problem any worse when just climbing up something steep and putting down power like 4-link and horst link setups will tend to.

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AJ_Barlas
+1 roil
AJ Barlas  - March 30, 2021, 6:48 a.m.

So true. Another point a friend reminded me of, in addition to the suspension points raised, is size specific STA. Just like rear centres, the STA changes from short to tall riders. Some brands are implementing this but very few currently.

andy-eunson
+1 Tjaard Breeuwer
Andy Eunson  - March 30, 2021, 9:38 p.m.

Tri bikes aren’t constrained by UCI rules otherwise tt bikes would have steeper seat tube angles. Tri and tt are all about aerodynamics. Flat back is optimal but that also has to be looked at with what that does to power output of the rider. There’s a story about Cancellara being stuck in the wind tunnel and it was determined that a flat back for him cost more watts than saved by raising his bar height a couple cm. In other words he made more watts than he lost by being less aero but more powerful. UCI goals are laudable. They want the best rider to win not the best bike. But the rules make fitting a tt bike to really tall and really short riders difficult.

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AJ_Barlas
+1 roil
AJ Barlas  - March 29, 2021, 9:32 a.m.

Great video too. I saw that right around when I submitted this article. He has a lot of interesting thoughts for sure.

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andy-eunson
+3 roil Andrew Major taprider
Andy Eunson  - March 29, 2021, 10:53 a.m.

No good bike fitter uses knee over the pedal spindle anymore. The good ones use seated balance. 

https://youtu.be/OyE67jKp1To

https://youtu.be/SZhWVZq2qUc

This is just one guy but I think his approach makes sense. For road. Off road we tend to spin more slowly. I’ve seen some articles recently that suggest that a slower cadence is more efficient.

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AJ_Barlas
0
AJ Barlas  - March 29, 2021, 4:29 p.m.

Interesting to hear, Andy. Thanks for the update. I haven't worked in stores, therefore am not around bike fitters, for many years now. Interesting to see that's evolved as well.

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moraucf
+1 AJ Barlas
moraucf  - March 29, 2021, 9:40 a.m.

Put me in the camp of have still not found a too steep seat tube angle, even on my G16. I have a few things working against me like my SQLab saddle, which I love but has a rearward seating position, and rearward cleat positioning which pushes hip rearward in relation to pedals. 

Still cant believe there is nobody making a forward offset dropper post with more than 150mm of travel (9.8 Fall Line R gets close but maxes out at 150mm).

Found this picture from 2013 when I used to run a specialized dropper reversed with forward offset. https://photos.app.goo.gl/wUx8pyLWHz6pChrJ7

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LWK
+4 Andy Eunson Andrew Major AJ Barlas Noel Dolotallas
LWK  - March 29, 2021, 10:17 a.m.

Great article, a few observations for me.  First, steep STA seem to be more important for taller riders.  Second, I would think the terrain and riding style would play into this.  "winch and plummet" is a fair bit different from long traverse pedal rides.  Noel Buckley had a good (IMO) synthesis of this in a recent comment in a different forum.  

People are talking lots now about size matched chain stays but seems to me the entire bike geo needs to change between sizes.  With carbon, you have different molds for every frame size regardless so this shouldn't be THAT big of an obstacle.  God forbid the manufacturer has to do a bit of extra thinking up front though...

Finally, AJ, do you have an idea what your actual STA is when climbing?  I think the main benefit of steeper STA is to stay in a better climbing position, especially with longer travel bikes with more sag.  So a static 78 turns into a comfortable 75-ish when actually riding, instead of a static 74 turning into a miserable 71, or whatever the value is, when sagged under rider weight and pedaling forces.

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AJ_Barlas
0
AJ Barlas  - March 30, 2021, 6:53 a.m.

‘the entire bike geo needs to change between sizes.’

Yes! We (bike dorks) keep focusing on size specific rear-centres but it should be everything, which includes STA. 

Not sure what my actual is but I will measure it soon. I’m keen to know at least my actual static and could probably get my sagged (static) too.

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andy-eunson
+3 roil taprider Tjaard Breeuwer
Andy Eunson  - March 29, 2021, 10:41 a.m.

I’ve searched for mountain bike specific fit studies and found nothing. While mountain, road and tri “engines” are all the same the fit requirements are different. Road and tri have to factor in aerodynamics and tri have to factor in running and how muscles are affected by doing both riding and running. Plus road bikes are somewhat constrained by ridiculous UCI tech rules. For Mountain we have to compromise fit for muscle use and technical aspects like descending and uphill tech. 

One thing road riders look for too is being balanced on the saddle. You don’t want to be leaning on the bars. So if you get on your drops or hoods and you can’t take your hands off without pedalling faster or engaging your core you need to change something. Often moving the seat rearward provides the fix. 

Mountainbikers tend to ride more upright anyway for descending and there isn’t really much need to be aero. Plus most riders have their feet further forward on the pedals which affects the hip torso angle and balance. But when I see a mountain bike set up with a seat that tips down I think that’s a response to a too steep seat angle and too low of a bar. If the seat is horizontal and you’re leaning hard on the bars you slide backwards. The fix isn’t tipping the saddle forward but moving it back, the feet forward, raising the bar or a combination of the three. 

I also think having the same rear centre length for all frame sizes is stupid and lazy. Some manufacturers are varying the rear centre but most don’t. Being short, I don’t have much issue with short chain stays but I sense the fix for tall riders looping out is the steep seat tubes. That affects how bikes fit me in a negative way. 

I don’t think slack angles are good though because full suspension bikes sag and change that and more so when climbing. One thing that would be nice is for manufacturers to pride sagged angles and not static. Most bikes run more rear sag that front so static angles aren’t really relevant other than for comparison purposes. 

This is an interesting topic for me. I think mountainbike geometry is still in a state of flux with respect to fit. Other geo aspects are settling out such as head angles, trail and offset. Good stuff.

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AJ_Barlas
+1 Noel Dolotallas
AJ Barlas  - March 30, 2021, 7:03 a.m.

“But when I see a mountain bike set up with a seat that tips down I think that’s a response to a too steep seat angle and too low of a bar.”

I believe the riders tilting the nose of their saddle down are looking for a more improved riding position and not countering the steep STA. If they had a shallower STA it would be even more drastic because of the search for a level seat while ascending. It makes sense but I’ve not found it to work well for me yet (everyone is different). As the bike tilts up hill, the saddle starts to tilt rearward, allowing the rider to slide backward while putting out hard efforts. To counter that, the upper body needs to engage again to hold the butt to the saddle, again creating extra effort, which negatively impacts efficiency. Tilting the nose down counters this, creating a solid perch to power from. 

You’re right, MTB geometry is still super young and we can probably expect to see it change a bit more before settling.

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yale986
+2 Mark Cr4w
Noel Dolotallas  - March 29, 2021, 1:50 p.m.

Great article and podcast AJ! 

I've been obsessed with the topic of STA and effective STA for a number of years now and have gone deep into the rabbit hole of secondary research including white papers, forum comments, articles, YouTube videos, as well as conducting primary research on the topic to gauge personal preferences. 

You're bang on in that most published studies and references are based on road cycling. Ultimately my research brought me to the conclusion, and personal opinion, that there is too much emphasis placed on the latter portion of "STA" acronym and not enough on focus on the comfort, performance, and efficiency gains from the "Seat" in that equation. No doubt STA is important but I feel it's just part of the issue. And as hard as it is to find MTB related papers on STA, it's harder still to find anything related to the effects of saddle angle on MTB. Likely the best paper on the subject specifically related to MTB was published in 2011 entitled "Adjusted saddle position counteracts the modified muscle activation patterns during uphill cycling."

No doubt the topic of STA is polarizing with many viewpoints and as many counterpoints. Ultimately, however, the main meta-issue we as rider's are trying to address is optimal positioning on a bike and in this case MTB. But that topic requires even more thought when you ask the question of what is the optimal riding position for: 

  1. climbing uphill vs
  2. bombing downhill vs
  3. riding undulating terrain

Disclaimer: I'm the inventor of the SwitchGrade which is a bolt-on saddle angle control mechanism that retrofits onto your existing seatpost. Basically it lets riders change the angle of their saddles while riding, separated by 10 degrees.

Sorry for the plug but just hoping to shed light on what we truly feel is a less talked about subject and one that we believe can be transformative. 

Commenters above pointed out that taller riders are most in need in steeper seat angles because of the how their CoM moves rearward and behind the rear axle. What the SwitchGrade does is complements your dropper post by preventing the dreaded backside slide and providing a solid push point to generate power and a steady, controlled cadence.

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AJ_Barlas
+1 Noel Dolotallas
AJ Barlas  - March 30, 2021, 7:08 a.m.

G’day Noel! I would love to pick your brain on the topic. No doubt you have much more time on the subject than I. Funny what you say about tilting the nose of the saddle down to create a solid push point, that’s almost exactly what I just discussed with Andy, above. Definitely interested to hear more. 

And thanks heaps for the link, I’ll give that a read!

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yale986
+1 AJ Barlas
Noel Dolotallas  - March 30, 2021, 12:56 p.m.

Happy to connect anytime on the subject! I’ve learned there’s so much at play when it comes to human kinetics / biomechanics compounded by cycling dynamics. It seems the more I dug the more I discovered on topic-specific information related to saddle tilt as well as slightly tangential but equally interesting topics related to STA and saddle tilt. 

Not only is there the science and theories but another factor is that many people are creatures of habit and may shun the notion of ‘change is good’. We recognize we have a lengthy education process ahead of us.  

In my personal long term testing of the prototypes, apart from the expected benefits derived by saddle tilt for climbing (ie keeping front end down, solid push point, less fatigue, more power) I’ve also experienced gobs more rear traction, especially on switchbacks due to proper upright (vs hunched) body positioning afforded by the saddle tilt. 

Will keep you posted as we learn more but in the meantime feel free to reach out anytime!

Noel

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craw
+1 Noel Dolotallas
Cr4w  - March 30, 2021, 12:24 p.m.

I love the look of this product. When will it be available for sale?

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yale986
0
Noel Dolotallas  - March 30, 2021, 12:57 p.m.

Thank you!! We’re pushing hard for a late spring / early summer launch but will be taking pre orders soon.

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craw
0
Cr4w  - March 30, 2021, 1:05 p.m.

Will you be doing a crowd funding campaign or just going live?

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yale986
0
Noel Dolotallas  - March 30, 2021, 1:11 p.m.

Still working a few things out but leaning towards just going live for first batches.

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Frorider
+3 Mark roil Tjaard Breeuwer
Frorider  - March 29, 2021, 6:21 p.m.

Isolating one factor (like STA) can lead to misleading conclusions.  For a taller rider like me, a steep STA is great provided the Reach has been lengthened enough that the ETT (that ancient metric) is long enough.  On the other hand, a slackish STA can feel ok on climbs if the CS length is long.  

Net net: I’m a huge fan of slack HA, steep STA, longish CS trend BUT all these factors can combine together to create a wheelbase that’s too long.   Fascinating article in Enduro mag that used timed descents to establish why pros avoid overly long WB....

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AJ_Barlas
0
AJ Barlas  - March 30, 2021, 7:12 a.m.

Do you have a link to that article, Frorider. That sounds like a great piece to tickle the mind.

You’re right, all measurements need to be taken into account, but it’s also important to think about each piece of the puzzle too. I actually believe the ancient ETT is still completely valid, it helps me get an idea of seated cockpit size when looking at bikes, which also needs to adjust for the steeper STA, in turn extending reach, as you mentioned.

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taprider
+1 Tjaard Breeuwer
taprider  - March 30, 2021, 2:58 p.m.

EWS professionals ride surprisingly short bikes – for good reason https://enduro-mtb.com/en/enduro-race-bike-mtb-review/

and more in my post below

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Glass
0
Glass  - April 5, 2021, 11:37 a.m.

Man that enduro mtb article has so many holes in it looks like swiss cheese! Pros ride bikes they are comfortable on. They don't do that much testing and they don't take the time to change riding styles to fit the longer bikes. Greg Minnaar is a great example of that. The guy has been riding for +20 years and only now is slowly realising that a longer bike is better for him! As for the narrower bars adding agility you can also do that by going with shorter stems eg 10-30mm. I think the pros ride narrower more due to avoid hitting trees during the race than anything else. I believe Jerome Clemence stated that in a bikecheck a few years back.

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syncro
+2 Noel Dolotallas AJ Barlas
Mark  - March 29, 2021, 8:26 p.m.

It's good to see the discussion include body position. The critical reference point is the BB. With older bikes the slack STA ended up putting your hips way behind the BB which is horrible for pedal power. The benefit of the steeper STA comes from moving the riders hips forward relative to the BB. Decreased angle at the hips (bent forward) and hips closer to or ahead of the BB makes a huge difference in the amount of power a rider can generate. Of course being too far forward or forward for too long is a drawback as it puts more strain on the lower back and shoulders/wrists, so there's a happy medium that needs to be found. So for mtbs, STA is only one part though of the bigger equation of overall bike fit. IMO for the average rider who just climbs up and descends, a position that puts their hips slightly behind the BB and their upper body bent forward about 35° will offer the best combo of power and comfort for climbing. On flat road a more upright position where you sit and spin will be more comfortable but it will limit your power generation for hills, especially steeper ones. I think with mtbs there are more sacrifices that have to be made for comfort due to the nature of the type of riding the bikes are meant to do.

The key thing to look at in the pics is the positioning of AJ's hips in relation to the BB and the rear axle. On the Evil he's much further back and on the Geometron he's further forward in relation to those two points. You can notice the same observation on the Specialized which is why he says the G1 fits better.

Edit: as most descending around here involves the seat all the way down, I set my bikes up from the perspective of climbing efficiency and power and deal with a more awkward flat pedaling position as I spend next to no time in that scenario.  The Switchgrade is a great idea that tackles the problem of seat angle. I also think there's a riser post out there that does this automatically as you raise/lower the seat.

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AJ_Barlas
+1 Noel Dolotallas
AJ Barlas  - March 30, 2021, 7:17 a.m.

Great observations, Mark. The dropper post with the automatically adjusting seat angle you mention is the Specialized Wu saddle. I don’t think it took off, with many riders not aware of the nose down tilt possibilities, or concerned with the extra moving parts. I don’t think they offered one with enough drop either (125mm max?).

In years to come we may find the Wu dropper was ahead of its time. Maybe?

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yale986
0
Noel Dolotallas  - March 30, 2021, 7:02 p.m.

Hey Mark and AJ! 

Yes the Wu had a lot of potential - I couldn't WAIT to get one! There's an article on a competing site where they interviewed the product manager behind the Wu. Apparently it was originally developed with a bias towards descending. I also chatted with one of their sponsored riders who, back in the day asked for it and got it, but lamented how he'd hoped it had less stack height and more travel.

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syncro
0
Mark  - March 31, 2021, 3:33 p.m.

The limited drop probably put a lot of people off, the idea is very good though and yeah, maybe ahead of it's time. 

Simple biomechanics tells us where our body position should be on the bike to achieve max performance. The problem is making the compromise for all the other variables - it's not possible to design the perfect bike.

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taprider
+4 Andy Eunson roil Nologo Reed Holden
taprider  - March 30, 2021, 8:41 a.m.

I disappeared down the internet rabbit hole looking for an answer

EWS professionals ride surprisingly short bikes – for good reason https://enduro-mtb.com/en/enduro-race-bike-mtb-review/, https://www.stevehoggbikefitting.com/ , https://www.renehersecycles.com/myth-5-an-upright-position-is-more-comfortable/

^ with sites like these for a start

some of my observations

1. The forward leaning torso angle of a road cyclist is not all about aerodynamics. Many of our muscles are used to keep us upright in a running and walking position; however, when those muscles do not have to do the work of supporting us upright, it spares energy and movement within the torso to breath deeper (such as you see when people squat over to recover their breath after running up stairs, or are having trouble because of some health problem)

2. When standing on the pedals, if the front centre is too long, your body has to do extra work to weigh the front tire adequately. Ideally, when standing on the pedals in neutral position, you can lift your hands and still be balanced over your feet and not tip forward, or use other muscles to maintain balance (partially reducing range of motion)

3. Riders have all different pedaling styles (heel droppers, toe tippers, flat footers, plus mid foot or ball over spindle variations) and seated postures (upright, leaning forward from the top of an upright pelvis, to a leaning forward pelvis with extended horizontal torso...). All these variation affect seat behind BB placement, seat angle and seat to BB length, but ideally, as with standing, you should be balanced enough to lift your hands off the bars without straining pelvic and torso muscles to maintain balance (tri-bars are an exception, but there still needs to be balance and lack of muscle strain to maintain position).

4. Road bike races can have steeper climbs than IMBA/North Shore trail standards. There are even road races that are just hill climbs, or up and over a mountain pass then plummet back down to the valley in a tuck. So mtn biking is not as much of a special case as many think.

5. As Tehllama42 already posted. There is a compromise between reducing tendency to endo vs front tire grip (for me after experimenting with an angle adjust headset, I chose front tire grip, since for an endo I can usually see it coming and anticipate; whereas, for cornering at the limit there is often no warning)

6. Road sprinters use a steeper seat tube than road tour-ers, since the sprinters need to reduce the transition between seated and standing (triathlon is even more extreme, but it is not about being dynamic on the bike).

So, even if my climb angle is 10 to 20 degrees, I don't think a 83 to 93 degree seat tube angle will be a good idea.

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roil
+1 Andy Eunson
roil  - March 30, 2021, 10:26 a.m.

Great stuff but I have some points on 2, 3 & 5.

The front center needs to be balanced with the rear center and the reach numbers play into this as well. Too many manufacturers design bikes with the same rear center (chainstay) and just increase the front center leading to an unbalanced bike. 

When standing on an MTB, we are typically in descent - on a decline as opposed to level ground. I don't see how the ability to lift one's hands off the bars without falling forward is applicable for this use case. That being said, rarely does anyone bring up the importance of stack height with respect to reach and its impact on body position and weight distribution. 

Every geometry is a compromise but would you rather have a setup that is well suited for the most challenging parts of the trail or the easiest?

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taprider
+3 roil Nologo Reed Holden
taprider  - March 30, 2021, 1:24 p.m.

To add to your comments.  Seat tube angle (providing your can drop your seat post) is not important when standing.

Also when going downhill, your body must resist braking forces, but also be able to un-weight the front wheel (so maybe long front and short rear is still effective, but I don't think that would be good for cornering, explaining why some EWS pros like shorter bikes).

For what I would set up the bike for depends on use?  For trials or slope style, then obviously set up for the most challenging, but for racing or all-round use (such as ride to the ride) then a set up that is most efficient, comfortable or fastest overall (and just be a little bit more careful for the most challenging parts).  Or what if your chosen most challenging parts are off camber slippery corners, and not Dansitions or jumps into rough landing zones.

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roil
0
roil  - March 30, 2021, 2 p.m.

100% to all the above

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RAHrider
+2 Andy Eunson taprider
Reed Holden  - March 30, 2021, 4:34 p.m.

Study on sta and efficiency

Google this and the first study I found showed a 72 deg sta was the ideal position for efficiency. Riders maintained 259 watts at 60 rpm and their muscle forces were measured. I like this study because it backs up what I think ;)

Taprider makes a lot of points that resonate with me. The balance point he is speaking of refers to a place where you are balanced on your pedals rather than tilting/falling forwards. This makes sense on a smaller wheelbase bike but on a long sled, you probably need the longer reach to weight the front wheel.

The article seems to assume that a steeper sta is inherently more efficient, if this was the case, why don't road riders and xc racers adopt it? Why can I find scientific studies that refute it? To use triathlon bikes to make any sort of claim is ludicrous. They are the least comfortable bikes to ride, handle poorly and are focused on reducing wind resistance over all else. 

In regards to the photos of you on your wife's and your bikes, why would you even bother comparing those? Showing how awkward you look on a bike that is 2 sizes too small really doesn't demonstrate much. The fact that your seated position is so similar demonstrates that your ETT onuour own bike is very short. As taprider elucidates, the harder you pedal, the lower your torso needs to be in order to counterbalance the driving force of your pedaling. With such a short ett, it would be uncomfortable to drop your torso towards your bars imo.

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AJ_Barlas
0
AJ Barlas  - March 30, 2021, 7:25 p.m.

Hi Reed. When I first saw your link I thought, finally, something that shows otherwise. As I mentioned in the article, I attempted to find studies showing benefits of shallower/more traditional STA but all I was able to come up with was something about casual/commuter bikes and running a lower seat height. 

Your study find was great until I discovered that it was conducted with a single virtual model. I may be wrong, but the software used (ADAMS LifeMOD) to do this doesn’t exactly validate their findings against the many I’ve been reading for the last 12 months that tested with human subjects pedalling physical, though often stationary bikes. I also mention that both road and triathlon bikes have been studied to show improved efficiency from steeper seat angles.  

I went into the research open minded and remain open. The fact is that at the moment, the science says steeper is more efficient but as Coach Harwood said, take that with a grain of salt. For that reason I rely on his expertise and experience and while he has personally found it more efficient, he notes that the human involvement—technique, position, flexibility etc—on the bike may have more to do with efficiency than geometry numbers alone. 

Itried to leave the article somewhat open in my closing, despite having not found sufficient studies supporting shallower STAs and efficiency. I did that because there’s much to learn and as mentioned, maybe we’ve already gone too far, perhaps not enough? We all need to keep an open mind to our habits, adjusting to change and possible rethinking of things, and that matters for either direction. But from my research and discussions with Coach Harwood, it seems there is some merit to the steeper STA we’re seeing. That doesn’t make it conclusive or right for everyone!

I chose to include my wife’s (too small for me, which I noted) bike because I was baffled that the centre to centre seat mast (extended) to bar was within ~5mm but they’re clearly very different. If you look at the photo on the equally XL Turbo Levo, the difference is more profound. And despite it having a motor, I find it problematic and causes back pains just like the old days. Unfortunately I didn’t get the images good enough to make the gif with that (sorry), but it is included for reference. 

Thanks for reading and your interest. I look forward to seeing how things evolve with our bikes in the future. As commenters have stated already, MTB geometry is young and there’s possibly going to be heaps of change over the coming years. I do hope we see more studies specifically on MTBs during that time. Maybe the manufacturers are doing some of this and that’s my next stop in the puzzle.

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RAHrider
+1 taprider
Reed Holden  - March 31, 2021, 9:15 p.m.

Thanks for the great response. I have to admit, I think you look cramped on the Geometron, but that is probably from years of road riding and being so used to a more traditional type of setup.

I only skimmed the article I posted and missed the part about computer simulation - good pick up on that. l still have a hard time believing that 100% of road and XC racers have it wrong. I think the studies may be thrown off by using inexperienced riders. I don't think traditional geometry is better for beginners. Most novice/intermediate riders (and mountain bikers) mainly power their bike through a forceful push down. Road riders who spend 1000's of hours developing a smooth cycling motion and are able to spin at 100rpm without any body bounce initiate their power earlier, when the crank is directly upright. The more relaxed geometry allows them to drop their heel and get behind the pedal driving it first through the top of the pedal cycle and then down the main push downwards. A steep STA robs you of the ability to drive from behind the pedal. Unless you had experienced cyclists in your study, you would never see a difference as novice/intermediate riders don't spin and don't initiate their pedal force as early. Also, a traditional racing geometry requires more flexibility in the back and hamstrings. A true racing bike is slow for a novice athlete because it is so uncomfortable. Their legs hit their belly and their back is rounded and pelvis tilted backwards because they are straining to reach the bars.

If you say that a steep sta is better for less-flexible untrained road cyclists, I would wholeheartedly agree. But I don't think Lance would be better off on a steep STA, I'm sure he tried it (he has tried everything else!).

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taprider
0
taprider  - March 31, 2021, 9:53 p.m.

"(he has tried everything else!)"

lol

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craw
0
Cr4w  - March 31, 2021, 9:01 a.m.

So if I'm reading this right, the study is based on an average person 178cm of height, 79kg of weight. The study also says that power drops off at steeper and slacker STAs for people of that height. No one is saying that steeper seat angles are necessarily better but they sure are for some people. I think mostly we're arguing against the general cycling notion that we're all the same and should be on the same gear and same setup.

It's the classic case of one size fits none. If you're not 178cm then you're on your own and will need to do your own math.

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RAHrider
0
Reed Holden  - April 1, 2021, 6:25 p.m.

I think you summed it up perfectly. In fact, I think a "racing", aka old school, geometry only works for about 10-15% of athletes. I'll be interested to see if racers start to adopt steeper sta's. I'm sure there are a few who lack the flexibility and may benefit from a steeper sta.

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Glass
0
Glass  - April 5, 2021, 12:15 p.m.

Road riders don't use steep seat angles because of the UCI restrictions. If they weren't in place road bikes would look very different. XC riders don't have those restrictions imposed on them but they tend to be a very conservative bunch (like their roadie counterparts). We are starting to see slacker and longer XC bikes so maybe in the next decade they will figure out what's actually best. 

I haven't tried a Trialthon bike but can say that road bikes handle like utter crap for the speeds and terrain they are riding in. Head shake on fast descents and toe overlap are clearly serious design flaws!

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taprider
0
taprider  - April 5, 2021, 8:38 p.m.

^BS! are you trolling?

Ok, I'll bite.

XC racers and coaches are constantly experimenting with and researching new technologies, looking for marginal gains. It's like Formula 1, but just with less money.

You should see the boxes of different lengths of cranks, stems, handlebars etc., and various shoe modifications, measuring instruments, plus journals/records of various experiments that the coaches of the Elite racers have.

Maybe mid race season, racers are hesitant to make changes if they are doing well, but it's full on mad science in the off-season.

Plus where do you get "road bikes handle like utter crap for the speeds and terrain they are riding in". Cornering at speed is what is important, not preventing endos. I have reached 98kmph on an old school Colnago on a dowhnill corner, and there was no shimmy or anything but a solid arrow like feeling

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Glass
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Glass  - April 7, 2021, 2:02 a.m.

Not trolling at all. I am dead serious. There isn't anything in mountainbiking or cycling close to F1. Road biking has had pretty much zero innovation (none in geo due to the UCI), a tiny bit in aero (also due to the UCI) some tyre stuff but the only big one was the leap onto disc brakes recently which took ages due to how conservative they are!

I can decend way more comfortably and faster on my DH bike on road than any roadbike ever! Cornering on a roadbike is utter garbage. They are fast (in a straight line) because they are light and have low friction but my god slam the brakes and try to lean that thing in a hairpin is frightening! These bikes average 30km/h and can easily do +90km/h on descents yet have the wheelbase of childs bike and the head angle of a unicycle! 

Just recently the UCI banned the super tuck, which wouldn't be necessary if they just ran a dropper post! The bikes can easily be under the 6.5kg UCI limit so it's possible to have a 6.5kg roadbike with a dropper post! The road bike world makes me laugh when they try to claim they have cycling figured out but they are still in the stone age!

I'll buy a roadbike the day they come with 67º HA, a decent reach, 50mm stems max, SA above 76º and chainstays above 440mm. You don't see a Yamanha R1 with roadbike geo for a reason!

The roadbike will only evolve geo wise if the UCI removes it's restrictions and companies and riders start real experimentation. Are 700cc wheels are even the best for road cycling?  I wish Chris Porter would try building a geometron roadbike, that would be an interesting experiment. 

The changes you mention in the XC world are microscopic, this is why almost every XC bike looks pretty much the same and not because they have been optimised. 

Have you seen a 66º HA, 500mm reach, 78º SA, 50mm stem XC bike? I have only seen negative rise 90mm stems, steep head angles, slack seat angles with offset seatposts.

XC still uses the road way of fitting taller riders onto bikes by slackening the seat angle on larger frames! There is some hope though as recently there has been a shift towards slacker HAs-

Having said all this, if you are personally happy on your roadbike that's great but don't try to convince me they are even close to the limits of what is most efficient or fastest. And please don't compare anything in cycling to F1 where real engineers do real testing to find the real limits of technology. 

Most modern mountainbikes brands are producing bikes with the same geometry as the Nicolai geometron from 2015 developed by Chris Porter 6 years later!!!

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Glass
0
Glass  - April 7, 2021, 2:02 a.m.

Not trolling at all. I am dead serious. There isn't anything in mountainbiking or cycling close to F1. Road biking has had pretty much zero innovation (none in geo due to the UCI), a tiny bit in aero (also due to the UCI) some tyre stuff but the only big one was the leap onto disc brakes recently which took ages due to how conservative they are!

I can decend way more comfortably and faster on my DH bike on road than any roadbike ever! Cornering on a roadbike is utter garbage. They are fast (in a straight line) because they are light and have low friction but my god slam the brakes and try to lean that thing in a hairpin is frightening! These bikes average 30km/h and can easily do +90km/h on descents yet have the wheelbase of childs bike and the head angle of a unicycle! 

Just recently the UCI banned the super tuck, which wouldn't be necessary if they just ran a dropper post! The bikes can easily be under the 6.5kg UCI limit so it's possible to have a 6.5kg roadbike with a dropper post! The road bike world makes me laugh when they try to claim they have cycling figured out but they are still in the stone age!

I'll buy a roadbike the day they come with 67º HA, a decent reach, 50mm stems max, SA above 76º and chainstays above 440mm. You don't see a Yamanha R1 with roadbike geo for a reason!

The roadbike will only evolve geo wise if the UCI removes it's restrictions and companies and riders start real experimentation. Are 700cc wheels are even the best for road cycling?  I wish Chris Porter would try building a geometron roadbike, that would be an interesting experiment. 

The changes you mention in the XC world are microscopic, this is why almost every XC bike looks pretty much the same and not because they have been optimised. 

Have you seen a 66º HA, 500mm reach, 78º SA, 50mm stem XC bike? I have only seen negative rise 90mm stems, steep head angles, slack seat angles with offset seatposts.

XC still uses the road way of fitting taller riders onto bikes by slackening the seat angle on larger frames! There is some hope though as recently there has been a shift towards slacker HAs-

Having said all this, if you are personally happy on your roadbike that's great but don't try to convince me they are even close to the limits of what is most efficient or fastest. And please don't compare anything in cycling to F1 where real engineers do real testing to find the real limits of technology. 

Most modern mountainbikes brands are producing bikes with the same geometry as the Nicolai geometron from 2015 developed by Chris Porter 6 years later!!!

Reply

DancingWithMyself
+1 Todd Hellinga
MuscogeeMasher  - March 30, 2021, 7:09 p.m.

Soooooo refreshing to see articles like this that are not feeding the new product and consumerism we can all slide into.  Changing the subject from pedaling to riding, I just built up a Banshee Titan for trips and the only niggle I have is that the saddle feels more in the way.  My everyday ride is an OG Hightower with a significantly slacker STA.  Both bikes have 185 droppers on them, as I couldn’t fit a 200 on the Titan.  However, unsure if 15mm would really make a difference.  Any thoughts on the topic, AJ?  Do I just need to get over it?

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AJ_Barlas
+1 DancingWithMyself
AJ Barlas  - March 30, 2021, 7:34 p.m.

Thanks, Masher. We’re trying to delve into things and get the thoughts going. This topic and the incredible discussion happening here in the comments has only stoked that fire more. There’s much to learn and discover!

You’re not alone with the seat feeling more in the way. I don’t have much info on it but anecdotally it seems to position in a manner that gets more in the way. It’s confusing because bringing it forward should make it easier to get behind it (not have to be as far back to do so) but the other changes in bike shape are planting us in between the wheels, having to deal with that pesky seat. I’ve been able to manage it by using longer drops, moving the seat lower and further away but it sounds like you may not be able to do that? What dropper post are you using?

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DancingWithMyself
0
MuscogeeMasher  - March 31, 2021, 5:05 a.m.

Running a BikeYoke Divine.  If went to a shimmed oneup might be able to squeeze out 5-10mm more drop.  But, really like the Divine and have Revives on my hardtail and trail bike and like the consistency from a service and spare parts standpoint.  Also, not sure 5-10mm would really make a difference.  Thoughts on that?  Every bike has a week spot, and think post insertion depth may be the Titans.  Plenty of room for 200 or 210 if I could insert the post deeper.  On an XL with saddle height of 780ish. Otherwise, loving the bike.

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AJ_Barlas
+1 DancingWithMyself
AJ Barlas  - March 31, 2021, 6:48 a.m.

I don’t blame you for the choice to stick with the Revive. They’re such a great feeling dropper. I’m not sure if a 5–10mm change would be enough to remedy your issue. Personally, the smallest change in drop I’ve done was 25mm, which makes quite a change but 5–10… mate, it’s probably not an experiment I’d want to pay for. Maybe an old solid seatpost that can give you that change is worth trying one day? 

You’re fully right, every bike has a weak spot, or two or three and nothing is perfect. It’s def worth trying to improve them though.

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DancingWithMyself
+1 AJ Barlas
MuscogeeMasher  - March 31, 2021, 5:23 a.m.

On a riding trip right now, but when I get home I’ll drop both saddles (both sqlab) and report on horizontal position of nose relative to BB.

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DancingWithMyself
0
MuscogeeMasher  - March 31, 2021, 5:23 a.m.

On a riding trip right now, but when I get home I’ll drop both saddles (both sqlab) and report on horizontal position of nose relative to BB.

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Suns_PSD
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Sun Hester  - April 3, 2021, 6:26 a.m.

Haven't found the limit yet to 'it's finally steep enough' but I know that I really dislike slack & 5 year old STA's.

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Glass
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Glass  - April 5, 2021, 12:20 p.m.

I agree. Would like to try +80º to see how it feels.

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Fahzure
0
Fahzure  - April 5, 2021, 8:06 p.m.

I'm at 81.5* on my G1 with custom extra long seatstay mutators. I'd like to try 82.5.

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geraldooka
+2 Tjaard Breeuwer Andy Eunson
Michael  - April 5, 2021, 8:11 p.m.

I don't think the benefits of steep seat angles are ubiquitous. I recently jumped back on my Knolly Endo (decidedly old school geo)  after more than a year on a custom hardtail that I had built with a steep sta, long reach and slack head angle and I was shocked at how much easier it was to climb a tricky technical switchback (Twister for the Victoria locals). Climbing that trail the very first ride on a bike I haven't ridden in a year blew my mind. It has nothing to do with traction I've never lacked it on either bike. It had everything to do with power. I could apply much greater leverage on the shorter bike both seated with the slacker sta and standing with the much shorter reach and steeper head angle... Honestly I did not expect that ride to go that way. It is a definite eye opener that perhaps I went too far in my design. The other major issue is I had hoped to use the custom as my ride to the trail bike but that steep sta (77deg at sag) makes for a terribly uncomfortable ride on anything flatish.

Having said all of that the custom is a fun bike to ride but its less me the operator and more me the passenger than my Endo. Its long reach and super slack head angle make it more confidence inspiring when barrelling down steep scary things than the Endo and its a hardtail! It is a solid up and down plow bike for sure but most definitely not an all rounder.

Looking at those pictures of you AJ; despite those big bikes you still look much more upright seated (and I'm running 20mm of spacers and a 45mm rise) than I do perhaps its more to do with my unusually long femurs and short torso its such a pain to get a comfortable seated pedalling position for me that doesn't compromise shred factor too much. 

I'm not sure I buy the adaptation to riding more forward as the better way to ride mountain bikes off road. My wimpy arms are no match for the power in my legs and large back muscles.

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Tjaardbreeuwer
0
Tjaard Breeuwer  - Aug. 24, 2021, 11:19 a.m.

I find it strange that you mention tri bikes vs road bikes. Yes, the unconstrained tri bikes use steep seat angles and are faster than UCI legal TT bikes, but that is because the steeper seat angle allows for a more open hip angle at the same torso angle or vice versa.

Basically when I do road or tri bike fits, I set the rider to the tightest hip angle (most aero) that is comfortable for them, and then on a tri bike the whole rider is rotated forward. This means with the same body angles and kinematics, they are more aero, thus faster on the tri bike.

Just like Joel Harwood says in the podcast, what matters is the angles and position of the rider, not of the frame. 

Are you saying you read tests where the rider maintained the same joint angles, yet was more powerful or efficient simply due to the more forward saddle position?

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Tjaardbreeuwer
0
Tjaard Breeuwer  - Aug. 24, 2021, 11:21 a.m.

My second question is for AJ and Joel Harwood: 

If I understand you correctly, you are claiming more glute recruitment (is possible) with a more open hip angle? 

I always thought it was the other way around? When your hips are completely opened up, there is no way to shorten the gluteus Maximus any further, so how can it do any work?

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Tjaardbreeuwer
0
Tjaard Breeuwer  - Aug. 24, 2021, 11:25 a.m.

A recent edition of German Bike Magazine had a group test of trail bikes, where they specifically complained that the steep seat tube angles and high stack led to poor climbing performance, making it hard to power up the climbs.

I am not sure what was in play, but interesting  that they found this noteworthy enough to mention it as a negative for the category in general.

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Tjaardbreeuwer
0
Tjaard Breeuwer  - Aug. 24, 2021, 11:25 a.m.

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