MEAT Engines 2023...

Andrew, in the spirit of your recent post. The original sketched drawing of Semi Rad's Did You Have a Good Adventure Chart.

https://semi-rad.com/2016/04/chart-did-you-have-a-good-adventure/

"The best exercise scientists are the athlete's themselves. Who through trial and error have found what works for them"

That only holds true if you want your “exercise scientists” to train one person - themself.

In my field I constantly see talented and experienced people saying a + b = c and making that a blanket statement without considering aspects d, e, f etc that are complex and personal and critical to getting the right answer.

Change the angle of some grips and all discussion of bar rise etc gets totally disrupted because the grip angle sends your elbows off in a different direction which means the feeling of the fit and steering is different due to your shoulder angles and how you load the bars.

It’s really really complicated.

Finding what works for YOU is the answer. And then if you want to advise people on what may work for them, don’t over-simplify and remember that every person is unique in their proportions, strength, flexibility, riding style, weight, etc. Blanket statements are good for marketing and very common in journalism but rarely helpful in coaching (beyond the most basic level).

Bar Roll / Height etc :

This is exactly the reason I am running a 0mm Effective Stem Length (bars rolled so the grip centre is on the steerer centre - typically a 12 degree bar needs a 31mm stem and a 15-16 needs a 40mm stem to get 0mm ESL with upslope parallel with head tube).  I use a string line from grip centre to grip centre then measure to the steerer centre wiht a square.

It takes the stem length out of the question and I can then evaluate the differences between different bar sweeps and bar heights.  Throw in some bar roll and there are too many variables.  I've taken the view that i'm not bothered about reach - I just want to fine what works best.  

Also - my 3 bikes have reaches of 441 (Krampus), ~480 (Solaris Max) and 515 (Murmur) and I have a similar butt to bar / butt to steerer on all three.  Therefore in my head reach is a bit arbitary - it is useful but not the be-all and end-all - it's more about how they ride.

It’s easy to forget that Reach & Stack came out as an effective way to talk about DH bike sizing and then Reach alone sort of morphed into a magical one-number frame fit predictor. 

There have been plenty of attempts to talk about bike sizing using one measurement- essentially to replace what we had with effective top tube length.

I’d say effective top tube - assuming companies clearly tell you where to measure from - is still the best predictor of if a frame fits or not. It ignores preference for seat tube angle and etc, but as your fleet shows, Marty, across a range of years and disciplines it does deliver results.

Posted by: AndrewMajor

It’s easy to forget that Reach & Stack came out as an effective way to talk about DH bike sizing and then Reach alone sort of morphed into a magical one-number frame fit predictor. 

There have been plenty of attempts to talk about bike sizing using one measurement- essentially to replace what we had with effective top tube length.

I’d say effective top tube - assuming companies clearly tell you where to measure from - is still the best predictor of if a frame fits or not. It ignores preference for seat tube angle and etc, but as your fleet shows, Marty, across a range of years and disciplines it does deliver results.

Agreed. I find ETT is my first concern. Reach and standover are obviously important, but irrelevant if ETT is too long/short.

I just demoed a Pivot but couldn’t make nice with the top tube length in size M or L.

Posted by: AndrewMajor

Posted by: Vikb

Posted by: BC_Nuggets

So is "overforking" the hardtail no longer approved?  ;)

The one HT I have that's overforked is to change the geo not because I need the extra fork travel. It just happens to have been what spare fork I had available and the combo worked great. Just looking at fork travel separate from geo I don't see the point in overforking to get and extra say 20mm of travel since the rigid back end has to get over the same stuff that fork does.

I'm pretty much sold on 140mm forks for a HT. You can get some of the more burly chassis in that travel length and that A-C plus a few spacers and a 50-70mm rise bar gets me into a comfortable riding position.

I’m generally happy with 120-140mm for the reasons you note, but, for example, I was running 170mm on my -2* angleset Honzo ST to get the geo I wanted and it was great too.

You're both making some great points.  With my current ride (2014 Rootdown with 140mm fox) I want to slacken the headtube (from 67.5 to 66 or lower) via a -2 angleset but I'm concerned about how I will get on with a lower bottom bracket as I pedal strike enough already (likely because I'm a hack.)  I think what I'll do is go ahead with angleset and see how it goes.  If I don't get on with it I'll maybe get a 150 or 160mm fork.  I agree though that travel wise 140mm is probably ideal and that a bigger fork would be more for geometry change and potentially beefier stanchions.  Either way I know I need to get a new fork soon as mine is old (original 34mm Fox RLC) and I really want something that's a touch stiffer laterally but has better small bump compliance.

Posted by: 4Runner1

Posted by: AndrewMajor

It’s easy to forget that Reach & Stack came out as an effective way to talk about DH bike sizing and then Reach alone sort of morphed into a magical one-number frame fit predictor.

There have been plenty of attempts to talk about bike sizing using one measurement- essentially to replace what we had with effective top tube length.

I’d say effective top tube - assuming companies clearly tell you where to measure from - is still the best predictor of if a frame fits or not. It ignores preference for seat tube angle and etc, but as your fleet shows, Marty, across a range of years and disciplines it does deliver results.

Agreed. I find ETT is my first concern. Reach and standover are obviously important, but irrelevant if ETT is too long/short.

I just demoed a Pivot but couldn’t make nice with the top tube length in size M or L.

Yeah man I'm with you, with the relatively large amount of time we spend trudging along uphill that saddle to bar ETT distance needs to be bang-on to the mm. Plus I can adapt to reach to a much greater extent as my ass isn't anchored in space.

As an aside, had same issue with Norco you're having with Pivot. Waffled between M and L, even after test rides. Personally, I went L. Slammed seat forward on rails for ETT. Installed high rise bars with some backward roll for reach. Presto, fits mint. Been on it happily a year.

Keep an eye on that wheelbase too I say, deserves equal weight ime.

-----------------

Just measured my effective stem reach. 9° sweep Raceface bars. 12mm in front of headset bolt when measured to center of end of grip.

Also measured 2cm in on grip where the outside pressure point of my palm is, 15cm in front.

Stuck a tight fitting allen key in the headset bolt and a straight piece of trim across the bars. Kind of a stupid method, allen key wobbled a mm forward and back.

Posted by: BC_Nuggets

Posted by: AndrewMajor

Posted by: Vikb

Posted by: BC_Nuggets

So is "overforking" the hardtail no longer approved?  ;)

The one HT I have that's overforked is to change the geo not because I need the extra fork travel. It just happens to have been what spare fork I had available and the combo worked great. Just looking at fork travel separate from geo I don't see the point in overforking to get and extra say 20mm of travel since the rigid back end has to get over the same stuff that fork does.

I'm pretty much sold on 140mm forks for a HT. You can get some of the more burly chassis in that travel length and that A-C plus a few spacers and a 50-70mm rise bar gets me into a comfortable riding position.

I’m generally happy with 120-140mm for the reasons you note, but, for example, I was running 170mm on my -2* angleset Honzo ST to get the geo I wanted and it was great too.

You're both making some great points.  With my current ride (2014 Rootdown with 140mm fox) I want to slacken the headtube (from 67.5 to 66 or lower) via a -2 angleset but I'm concerned about how I will get on with a lower bottom bracket as I pedal strike enough already (likely because I'm a hack.)  I think what I'll do is go ahead with angleset and see how it goes.  If I don't get on with it I'll maybe get a 150 or 160mm fork.  I agree though that travel wise 140mm is probably ideal and that a bigger fork would be more for geometry change and potentially beefier stanchions.  Either way I know I need to get a new fork soon as mine is old (original 34mm Fox RLC) and I really want something that's a touch stiffer laterally but has better small bump compliance.

A ~160 fork with reduced air volume to ramp out the last 20mm could be a linear ~140 fork with a higher crown.

Posted by: velocipedestrian

A ~160 fork with reduced air volume to ramp out the last 20mm could be a linear ~140 fork with a higher crown.

I like the way you think!

Posted by: Hepcat

Just measured my effective stem reach. 9° sweep Raceface bars. 12mm in front of headset bolt when measured to center of end of grip.

Also measured 2cm in on grip where the outside pressure point of my palm is, 15cm in front.

Stuck a tight fitting allen key in the headset bolt and a straight piece of trim across the bars. Kind of a stupid method, allen key wobbled a mm forward and back.

Now have a baseline measurement to compare for steering feeling.  For me this helps to get a consistent setup when experimenting.

Posted by: AndrewMajor

It’s easy to forget that Reach & Stack came out as an effective way to talk about DH bike sizing and then Reach alone sort of morphed into a magical one-number frame fit predictor. 

There have been plenty of attempts to talk about bike sizing using one measurement- essentially to replace what we had with effective top tube length.

I believe Turner and Transition lifted reach and stack from the triathlon world. Sort of prehistoric/geometric versions of 150mm cranks and 80 degree seat angles. It made some sense to use reach and stack for DH bikes since you started to have a) huge variance in seat angles, b) very little variation in head tube length, and c) bikes that you don’t ever ride seated.  

ETT stopped being a good proxy for saddle to grip length (ie bike size) in normal mountain bikes when a critical mass of bike manufacturers decided that they had to bend or interrupt seat tubes (usually to make the chainstays shorter). Like reach, it is also very hard to measure accurately. In some respects, perhaps hard-to-measure is good for brands since you only need a keyboard to ‘have’ the longest bike out there and factory qc gaffs are much harder to catch.

If pressed, I would go by front center as a single fit metric when I’m comparing bikes of similar intentions. Stack and reach to the bottom of the headtube would be ok as well, though again, it’s not really measurable.

Posted by: a.funks

"The best exercise scientists are the athlete's themselves. Who through trial and error have found what works for them"

That only holds true if you want your “exercise scientists” to train one person - themself.

In my field I constantly see talented and experienced people saying a + b = c and making that a blanket statement without considering aspects d, e, f etc that are complex and personal and critical to getting the right answer.

Change the angle of some grips and all discussion of bar rise etc gets totally disrupted because the grip angle sends your elbows off in a different direction which means the feeling of the fit and steering is different due to your shoulder angles and how you load the bars.

It’s really really complicated.

Finding what works for YOU is the answer. And then if you want to advise people on what may work for them, don’t over-simplify and remember that every person is unique in their proportions, strength, flexibility, riding style, weight, etc. Blanket statements are good for marketing and very common in journalism but rarely helpful in coaching (beyond the most basic level).

It is complicated. But even if your coaching your still trying to find a way to make it work for the individual athlete. Won't touch the high performance side as spend way too much time immersed in that through my wife's work. Stay away from parents of athletes for a reason.

Reality is unless your fighting for a position on the World Championship team the majority of riders don't need to worry about numbers and whatever formula. Biggest improvement have seen riding wise with some have helped is....getting them comfortable on the bike.  Funny thing have an friend who a year ago switched to gravel full time from road. Commented the bike was causing her back to ache and a few things. Asked if she felt comfortable on the bike and she said no. She got the bar raised a bit and not only comfortable and enjoying it more. Said she is riding better and so on.  Funny thing is she said was the first person she talked about it with that asked her that question. Didn't bring up tape measures and that.  Some how this has led to me coaching her a bit to get better at riding gravel.

for my needs, i like downtube length as a real-world easily-measurable-with-tape-in-hand front/center comparator.

Posted by: Blofeld

Posted by: AndrewMajor

It’s easy to forget that Reach & Stack came out as an effective way to talk about DH bike sizing and then Reach alone sort of morphed into a magical one-number frame fit predictor. 

There have been plenty of attempts to talk about bike sizing using one measurement- essentially to replace what we had with effective top tube length.

I believe Turner and Transition lifted reach and stack from the triathlon world. Sort of prehistoric/geometric versions of 150mm cranks and 80 degree seat angles. 

Dan Empfield wrote about reach and stack a lot. 

https://www.slowtwitch.com/Bike_Fit/Road_Bike_Fit/Reasonable_bike_fit_expectations_3595.html

Have no clue why reach and stack from the triathlon world would work on a mtb. Reality is set up of a tri bike is around the basic idea of going say 40km in a TT position.  Other then corners and standing to climb any hills there is very little change in rider position. Riding a mountain bike has way less staying in one rider position due to terrain.  Unless they thought it was a way to sell you more shit.