EDITORIAL
Dreaming Of Crate Suspension
Buying Backends
Let's talk about Ventana and Titus; two American-made mountain bike brands with in-house full-suspension frames. Titus has since changed hands and it's been years since they manufactured a bike in the US of A but here I'm talking about their polished silver Horst-link rear ends when Chris Cocalis, now of Pivot, ran the company. Ventana is still making bikes in Northern California including their line of walking-beam faux-bar suspension bikes.
The commonality between these brands, and this is by no means an original idea, is that they both sold their rear suspension platforms to smaller builders looking to offer a combination of a proven full suspension system, with lighter-weight aluminum stays, and whatever custom geometry you could imagine for a steel or titanium front triangle.
Fast forward to 2021, and there are a number of interesting, and excellent, full-suspension platforms on the market and I'm particularly interested in flex-stay platforms like Specialized's Stumpjumper, Kona's Hei Hei, and the Canyon Lux Trail I'm currently testing. These rear ends are light and have a clean and simple aesthetic that hides the effort that goes into making them ride well. If I was acquiring a custom-geometry full suspension bike I would love to combine a steel front triangle with my choice of geometry with a carbon crate rear end from a major manufacturer.
The Vicious Cycles Groover, Groover LT, and Groover 29" used Horst-link Titus Cycles rear ends with custom steel front triangles. (Photo: Vicious Cycles)
I've seen Waltworks bikes with Trek Slash and Fuel rockers and steel back ends, but Walt's also one of the builders that's worked with Ventana rear ends. (Photo: Waltworks)
In the case of the Canyon, while it's a 110mm travel, light-trail bike, it's tested to the same Category 3 standard to which they subject their 5" travel bikes so it should perfectly complement the 130mm forked, 64-65° head tube angle, North Shore Tech-C bike that I'd order.
The average 2:1 leverage ratio (110mm travel from a 55mm stroke shock) lends itself to a wide variety of shock options whether I want to save some money and run a more basic damper like the SR Suntour Edge, install a super-light option like the Canyon's stock SIDLuxe, or run a top-performing mega-tuneable inline shock, like Cane Creek's IL Air.
The custom steel build is going to add some weight over the Lux Trail frame's 1905 grams (no shock) but the rear end and linkage would save weight over a full steel build and, more importantly, bring to bear an extensive amount of materials design and engineering that a small builder can't match. That's not a dig on smaller manufacturers who in many ways are driving the bus when it comes to geometry and kinematics, but strength-to-weight ratios and carbon layups are the purview of big manufacturers.
I'm imagining combining the 110mm travel, lightweight, carbon, Canyon Lux Trail rear suspension platform with a custom steel front end with the geometry of my choosing. (Photo: Deniz Merdano)
Canyon doesn't even sell Lux T frames, never mind rear ends, but all I'd need is a linkage, one-piece stay assembly, and the optimum pivot locations to get a front end made. (Photo: Deniz Merdano)
I'm very much into the concept and aesthetics of a flex stay rear end so that's where my focus is as I write this piece. The Kona Hei Hei or Specialized Stumpjumper would also be interesting options. (Photo: Deniz Merdano)
I'm daydreaming about the perfect full suspension trail bike for the UROC trails I was recently riding. The front end of my Waltworks V2 but with a 1-2° steeper HTA, the back end of the Canyon Lux Trail, an SB ONE chain tensioner, and a micro-drive single-speed ring and cog setup. Beautiful.
There are many takes on the best geometry for any given locale, as well as preferences for suspension designs and travel, making for limitless combinations. A Trek Slash with DH geometry or a Kona Operator with a full-length seat tube for pedaling? A Pivot 429 rear end with the front triangle dimensions of a new Firebird?
The issue is, of course, that many companies do not even sell frame-only options and quite a few that do charge nearly as much for their frames as the entry level of their complete bikes. So it’s a big ask, for them to start offering rear-triangle sets to small builders as. It could however, be a great incubator for ideas to see what custom builders, and their patrons, do with them.
All that aside, given any option, what would you build?
Comments
Cee Cee
2 years, 7 months ago
Sorry, this is a custom steel mainframe-only men's support group...don't worry, Walt will know where to position the rocker
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Tim (aka DigitBikes/DirtBaggies)
2 years, 7 months ago
The primer I painted it with had that rusty hue!
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Andrew Major
2 years, 7 months ago
Hahahahahaha.
Hey, you have to give props to Frank The Welder - FTW, Sinister, etc. There’s some nice custom aluminum out there!
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Kevin Bond
2 years, 7 months ago
I love my Hardtail, but would spend all my money on a layout with similar efficiency, and power transfer, but a little less bike to rider violence when things get rough, or choppy.
I had a 2013 Hei Hei with flex stays and hated it, but that was aluminum. I’m sure carbon is better suited for flex stay applications, but I’m still a bit wary. Seems anything that flexes will only have so many flex cycles before it eventually fails. Sure a lifetime warranty may help, but a lifetime warranty won’t walk my ass out of the woods with a broken frame.
Perhaps some sort of revamped strut layout like the old Rocky Mountain Razor Back? Or a maybe a soft tail?
Any experience with the Spur?
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Andrew Major
2 years, 7 months ago
My aluminum flex stay experiences are poor, and when I asked Canyon they ~ said they won’t do it for the fatigue reasons. On the other hand the Hei Hei is awesome, carbon Stumpy is awesome. I’m very down with flex stays.
This piece features the Lux because I’m riding it right now. I haven’t ridden the Spur but it gets great reviews within its box and every Transition I’ve ridden has been immediately fun. Lots of great candidates.
I can imagine a lower slacker Banshee Titan too, with the actual STA kicked out to allow a longer dropper.
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Cr4w
2 years, 7 months ago
Titanium could accomplish this pretty well. I had a Ti softtail back in the day and while it was sort of great it was too flexible for me when things got really rough. I'm on a straight gauge ti frame now and it's got all sorts of compliance happening that you can feel while you ride. For sure a part of that is the long tubes on my giant bike but it doesn't feel noodly/whippy or out of control. It feels smooth. But it's not suspension. And requires Cushcore Pro and heavy tires to be ridden really hard with any confidence.
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Andrew Major
2 years, 7 months ago
You still can’t engineer titanium to flex in some planes, but not others, to the extent that you can with carbon and drawing and bending custom tubes is expensive. Also you get specific stress risers at welds that you can engineer out with carbon.
I’m not generally a carbon pusher, but I’ve owned and ridden enough different Ti bikes I would choose carbon for this application.
Same argument for carbon over steel if we’re trying to make a true FS bike.
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ackshunW
2 years, 7 months ago
Sure you can! Flat plate sections and/or heavily ovalised tubes.
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Andrew Major
2 years, 7 months ago
I’m not generally the one sticking up for big carbon but even the most manipulated ovalized tubes and flat plate aren’t going to give you the control over how and where the material flexes that you get from carbon and unless you are going to hydroform whole sections the high stress welded areas are still the biggest issue other than cost.
I think a hybrid frame of a big brands carbon rear end and a lightweight Ti front end could be cool. Actually, the only good Ti FS bikes I’ve ridden combined aluminum back ends with Ti fronts. I’m challenged to think of a single good example of a full-Ti FS bike.
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DadStillRides
2 years, 7 months ago
Taking your argument/thought experiment a step further, couldn't it be said that carbon is the superior material for what you desire in a front triangle too? We all like the subtle flex/damping characteristics of steel, but I've been wondering lately with all the specific traits manufacturers are able to achieve with carbon design, layup, weave if they couldn't mimic the feel of steel, but you know.. do it better and lighter (I say all this as the owner of an aluminum full-sus, steel hardtail, and steel dj).
Andrew Major
2 years, 7 months ago
I don’t necessarily disagree assuming you’re ordering a minimum number of frames to cover costs (moulds, patterning layups, etc).
But, front triangles are generally easier than rears for FS and I want to take the advantages of the rear (manufacturing, materials, engineering) and get a custom front end that I doubt any company is going to want to build hundreds of.
Heinous
2 years, 7 months ago
@dadstillrides - Carbon has so long promised to mimic whatever we want it to, but I'm yet to ride a carbon frame that feels like a good steel or ti one. There are many great carbon frames, for sure.
Andrew Major
2 years, 7 months ago
Now that the standard tire size for XC racing is a 2.4” and there are abundant 2.6” options I think weight and strength have taken precedence over ride tuning - especially on FS bikes. And stiffness is very much vogue right now (see 38mm stanchions).
Some of the stuff I’ve seen in terms of the potential flexibility of carbon (particularly with bars - check out Regular Cycles / Drew Diller or SQLab) makes me think of the possible rather than the reality.
Vincent Edwards
2 years, 7 months ago
I know it partially misses the point of this article- but the Spur will take an Angle-set. A Spur with a -1 and a 130mm fork would get you close to a 64.5 degree HA.
To the bigger point though- it would sure be nice if more manufacturers used IS headtubes to allow for HA customization.
__
… if you can find a rear swing arm assembly to do this with- I look forward to the next article!
(I wonder if placing a wanted ad might turn something up? Most swingarms are not size specific- what you need is someone who has a bike that’s no longer under warranty with a broken front triangle…)
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Andrew Major
2 years, 7 months ago
For sure! A Kona Hei Hei with an Angleset and a 140mm fork would get me there too. Actually, taking the Point8 IS Angleset into account (current and future) there are quite a few stock bikes that could work.
Specialized Epic Evo with a -1.7*!? Yum.
I actually was very hesitant to write this piece for that reason but at the end of the day it was too easy not too - I mean I dreamed it up.
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Velocipedestrian
2 years, 7 months ago
Lots of V2 Banshee Spitfires cracked on the downtube ~10cm ahead of the seat tube... There are back ends around.
(mine hasn't yet, but I'm dreading the day).
Not flex stay, but a tough rear triangle with the right amount of travel designed for a straight seat tube.
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Andrew Major
2 years, 7 months ago
The dual short links may be harder to build a front triangle around? There’s a lot of force on the frame at the lower link (which may explain the crack).
I do love the idea of reusing the backend / updating a bike you love. I wonder if there’s any way to squeeze a bottle mount in at the same time?!
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Velocipedestrian
2 years, 7 months ago
Longer head tube + longer reach = more space inside the triangle... There's almost room for a bottle there on my large, so should be possible with a steel front end.
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Cee Cee
2 years, 7 months ago
I dream of a lightly used current gen Stumpj--which already has the desired dimensions--for less than full retail
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Andrew Major
2 years, 7 months ago
Current flex-stay Stumpy with the Geo I want for less that the frame-only SRP sounds delicious!
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Cee Cee
2 years, 7 months ago
What's wrong with already existing frame geo? HTA will go sub-65 in low w/ Mezzer at 150 leaving extra room to tune the spring, wheelbase 1230mm, reach 480mm on S4. Isn't this right in line with your Alpine Trail?
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Andrew Major
2 years, 7 months ago
I mean, first off the Alpine Trail is a stock frame, not necessarily what I’d build myself. Also, my AT has the, slacker, previous generation STA.
There are a few things I don’t love about about the Stumpy that I would change. STA is one of them.
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Velocipedestrian
2 years, 7 months ago
A local (to me) guy built a front for a broken SB5.5
There is a multi-page story on the process in Spoke 82, but they seem to have kept it print only. I'll just tease with more pics here.
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fartymarty
2 years, 7 months ago
With some slacker, longer geo that would look amazing.
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Andrew Major
2 years, 7 months ago
Hahaha. That was my first thought too. But as I’m regular reminder there are places where my geometry preferences may not be the most fun.
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Velocipedestrian
2 years, 7 months ago
Yeah, I think it was more of a learning curve for the builder - I seem to remember he kept the stock geo.
If my Spitfire cracks in the usual spot, and I'm at liberty to go down this rabbit hole, I'd be tempted by a 29" front with a taller head tube, steeper SA, +20mm reach and a HA of 63°/64° (with the dropout adjustment) @140mm fork. Hopefully that would also give space for a bottle inside the triangle.
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Andrew Major
2 years, 7 months ago
Ooooo. That’s a beauty. Especially with the Turquoise colour. What a PIA to build it around the SI like though… must weigh a ton.
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Velocipedestrian
2 years, 7 months ago
Same rear, and answering some of the geometry critique.
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Velocipedestrian
2 years, 7 months ago
The SI cage does look super heavy, but it's weight in the right place at least.
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Heinous
2 years, 7 months ago
I suspect Ventana could make rear ends available because they weren’t frantically manufacturing warranty ones for themselves.
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Andrew Major
2 years, 7 months ago
I’m not sure who that’s a dig at, but I don’t disagree. I know when Brodie switched to a seat stay pivot from a Horst link (way back in the day) their warranty rates on rear ends went way down. That Ventana rear end is tough without being a tank. It would have been one of the best options back then.
That said, see a lot less failures these days. Manufacturing and materials have come a long way.
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Hugo Williamson
2 years, 7 months ago
And Turner aficionados, try as they might could not tell the difference between the Horst and seat stay pivot locations!!
Which has a lot to say about the various suspension designs!!
Shock tune to specific design may be more important?
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Andrew Major
2 years, 7 months ago
I’d argue it doesn’t say much really, see ‘Starling Fallacy’ comments below.
Everyone I know personally who owned a Turner never owned another after they switched from the Horst Link, except two riders who bought DW versions more recently. Can’t read too much into brand loyalists switching Kool-Aid flavours. It’s still Kool-Aid.
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Heinous
2 years, 7 months ago
I should be clearer. It wasn't a dig so much at any builder, but many. The flex stay designs are popping up with reduced warranty periods and I can't see many builders who put their names on the side of a frame taking the risks associated with third party rear ends that aren't as durable.
There does appear to be accessible software for modelling and designing suspension now though (racooz, linkage) which might facilitate home builders just like BikeCAD has.
I've spoken to more than one super high end Ti builder over the years who'd toyed with buying rear ends off big guys but nothing ever came to fruition.
I do totally agree with your comment on shed magic and steel though. I was about to order an Actofive when they were steel, and the change to solid alloy (literally two solid pieces) just lost all romance and promise of supple feel for me.
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fartymarty
2 years, 7 months ago
My "what would you build" bike would be a 29er Starling with the geo of the Transition Spur - and built light and 120mm each end. Something that would be somewhere between my Murmur and Krampus. Simple and full steel so it can take a beating.
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Andrew Major
2 years, 7 months ago
I believe you totally would, and I might too if it weren’t for what I call the Starling Fallacy.
The Starling Fallacy holds that somehow great geometry and shed manufacturing can overcome the performance issues of a true single pivot bike. And, since we know that great geometry is free and easily duplicated we can further boil down the fallacy to say that shed manufacturing alone can overcome said issues. You don’t even have to produce all your bikes in the shed - just some of them.
And so, riders who absolutely would not accept the performance of a simple no-linkage true-uni-pivot design from a major manufacturer or even a smaller manufacturer (see riders talking about Orange bikes) will gush about the descending prowess of a Starling.
Just imagine the shit talk if Cannondale launched a modern version of their Prophet - light, simple… oh, “it sucks when braking, etc etc etc.”
…
Anyways, my idea here is to combine custom manufacturing with top-end rear suspension systems to get custom geo with the best performing rear suspension.
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fartymarty
2 years, 7 months ago
OK then I guess if I were Frankenbiking (or is that Frankenframing) which I would probably never do (as it's well out of my comfort zone) is to put an Atherton / DW rear on the back off a full Ti front end.
Or maybe a Yeti slider rear on a Ti front end or maybe even a Norco Range carbon rear on Ti front... (you see where I'm going with this).
I would still take the Starling or your new and improved Prophet though.
You still need to get yourself a Beady Little Eye - crowd fund it and I'll throw in a fiver - a proper fiver at that (£5).
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Andrew Major
2 years, 7 months ago
Hahaha. I see where you’re going. I get it, but I’d go stainless steel v. Ti to remove the manufacturing headaches. My Ti experiences have been very mixed.
I can’t sign up for around-the-BB pivots. I’m not writing off the idea of an FS/SS but I’d use a tensioner as much as that’s extra complicated v. the BLE. I could certainly see a slacker HeiHei with a double lockout in the distant future.
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Zero-cool
1 year, 9 months ago
The Starling stainless steel hardtails do look very nice but for that money I’ll be going for a 29er built but Curtis (just up the road from my house)
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Andrew Major
1 year, 9 months ago
Does Curtis build in Stainless? I know a few small builders who will.
nothingfuture
2 years, 7 months ago
That's been done, actually- a long time ago. Independent Fabrications built a Ti front end that mated to an aluminum DW-Link rear end (made by, I think, Devinci?). It was called the Tungsten Electrode, and I think they made *one* of them.
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Andrew Major
2 years, 7 months ago
They made a few… some look like Pivot rear ends but certainly Devinci used to build for other brands going back to the birth of the company and it wouldn’t surprise me if they built those too. Hardly current though and Titus had plenty of options back then for Ti front / aluminum rear.
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Hugo Williamson
2 years, 7 months ago
The problem ( if any) with Starling is the chassis without shock, is the same weight as a Geometron, or Raaw Madonna chassis. Both, arguably a superior bolt on rear suspension , if it were possible.
There lies the problem with a steel front end, being its inherent weight, irrespective of a bolt on rear end.
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LAT
2 years, 7 months ago
this is an interesting topic and one i pondered myself before i sold my original tallboy frame, but if you want to combine custom manufacturing with top-end rear suspension, you may need a Nicolai.
and your starling fallacy is a fallacy! i know because i own a murmur and it’s perfect.
kidding aside, perhaps those skinny tubes in the swing arm enhance the performance of the single pivot in some flex-stay kind of way.
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Andrew Major
2 years, 7 months ago
Believe you me, I know enough Starling fans & owners* that I never discuss the Starling Fallacy in public lest some rabid stranger attacks me with their EDC tool. My only escape would be to yell something bad about Banshee's cable routing or frame sizing and then drop to the floor and hope the fanboys would take each other out while I crawled to safety.
*I know saying "fans & owners" sounds redundant but Starling is one of those companies where people who've never so much a glimpsed one in real life will go full Man-On-Fire on you in an effort to make you see that they're the best riding bike on the planet.
**I have not ridden a Starling-Starling. But I've ridden lots and lots of Starlings if you know what I mean. I like them, a lot, except for the ones that EAT shocks because they rely on them too much as a structural element (note, many multi-pivot bikes do this too) but true uni-pivots are much more quirky to ride than a VPP, DW, Horst Link, (good) Linkage-Driven-Single-Pivot, Split-Pivot, SwitchInfinity, etc. There's a solid reason all those bikes have lots of bearings.
If Cannondale had released a modern Prophet I would have been stoked and they would have sold next to none. Same for a modern meat-motored Heckler/SuperLight, or the twenty-year-old Marin B-17 (I always thought they looked good).
If telling yourself that the frame material that adds the je ne sais quoi factor works for you I'm fully in your corner! I truly think bikes do ride significantly better when we apply personal value to them - at least that's how it works with my Waltworks.
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LAT
2 years, 7 months ago
good answer on many levels
great article, too. many thanks
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fartymarty
2 years, 7 months ago
The first rule about the Starling Fallacy is that it is a Fallacy... or the Starling Fallacy Fallacy.
On a slightly more serious note I think Starlings ride well because they are steel and not over built - good design if you will. Also as you note I think the slight bend in the seat stay adds to the bottomless feel of the suspension by aciting like a leaf spring.
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Andrew Major
2 years, 7 months ago
I think good geometry does more than most folks give it credit and also that no amount of flex in the frame material of your uni-pivot bike makes up for the braking characteristics for which other similar uni-pivot bikes have been shit on for 20-years.
I think the je-ne-sais-quoi performance factor is you and the beyond-a-thing qualities that you put on the bike.
Not saying that isn’t awesome, and the bike isn’t awesome, or even that it wouldn’t be the best bike design for most riders (I think a lot of folks have bikes that are over complicated for their needs) but no shed magic or material is going to change the basic nature of how it works.
And how it works may be the best compromise for some terrain! Certainly wasn’t my goal to debate the best choice is suspension platform. That’s why I structured this around carbon flex-stay back ends.
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fartymarty
2 years, 7 months ago
Completely off topic but it would make an interesting piece either on NSMB or MeatEngines about suspension designs and how they are / aren't applicable to certain riding locations.
For example I love the Yeti sliders but there's no way I would ever ride one in the UK especially in winter (the same goes with a lot of multi pivot bikes). If I lived in California it would be a different story.
I guess this is the reason you see a lot of "simple" designs from the UK as the weather allows all year riding but the conditions can be crap in winter - lots of jet washing = new bearing every year therefore less pivots = less £££. OK they don't work quite as well but it's worth the compromise.
Andrew Major
2 years, 7 months ago
The issue would be what example you choose to go with.
For example the first horizontal-shock Process bikes from Kona (111, 134, 153, 167) have massive bearings and wicked shielding. I know folks riding hard year round that got multiple seasons on a set of bearings.
Plenty of similar bikes out there where you can see the bearing seals that might, might get 100hrs of riding.
Same could be said for different uni-pivot designs.
I mean, if it was a MEATpiece it would start by eliminating anything with an ‘Onion’ mount. Hahahahaha
Hugo Williamson
2 years, 7 months ago
Andrew
Given my reply to one of your previous comments, Re Turner Horst to seat stay pivot, and none of the Turner crowd could tell a difference when ridden in the dirt, my question is “ what is a top end suspension?”
I have a single pivot, a linked single split pivot ( similar to a Trek) and a short link multi pivot ( CVA), all very similar geometry, yes there is a difference, the CVA, being the most plush, but the most fun and feel, I’m afraid goes to the shortest travel SP!! So which is “best?”
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Andrew Major
2 years, 7 months ago
Hi, I answered your response re. Turner fan boys.
It wasn’t really my goal to debate which suspension design is best as I think for most riders it’s whatever design is present on their favourite bike (which combines a lot of factors), plus different terrain, plus setup, plus plus.
That’s specifically why I’ve stuck to framing the piece around, and mainly making comments about, advanced carbon flex-stay designs, which would require the kind of builder-hybrid I’m talking about here to combine with a custom geo front end.
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Andrew Major
2 years, 7 months ago
This is from a comment below (thanks olaa), and is a very neat execution of a custom steel front end a d the carbon back end from a Scott Gambler. It’s the sort of factory-looking custom combination I’m imagining:
https://www.vitalmtb.com/forums/The-Hub,2/Bike-design-as-a-hobby,10880?page=2
I think there’s something to be said about how clean it looks. It’s certainly what I’d picture attaching a Lux rear end to a custom front.
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Zero-cool
1 year, 9 months ago
Orange bikes do descend really well but snobs (and people who’ve never ridden one since 2012) just whinge about single pivots being being rubbish and the fact the welds aren’t perfectly straight. My 2012 Alpine 160 (with offset bushings & a -1.5 angleset was one of the best bikes I’ve ever ridden).
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Andrew Major
1 year, 9 months ago
I’d love to spend some trail time on a current Orange. One of bikes at the top of my list for frames I’d like to review.
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ackshunW
2 years, 7 months ago
Good article! While we’re dreaming, I’d take a Nicolai rear end, with the mutators & everything, on a custom steel, no make that Ti, front end.
In my version, the rocker pivot and forward shock mount are both part of one big machined piece that bolts to the downtube, for excellent alignment and future-proofing.
My custom geometry has a stretched reach for a really short stem, but steeper-than-current head tube, like 66. I’m going on the theory that front center is more important than head angle for my riding.
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Andrew Major
2 years, 7 months ago
Cheers!
I purposely left out Nicolai as it’s my understanding that with a pallet of money they’ll build whatever geometry you want? Plus their suspension system stacks up against the big players so arguably (other than potential weight savings from say a top-end carbon rear end) they’re delivering what I’m on about already!
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ackshunW
2 years, 7 months ago
Hahah yeah I think I missed your point a little. I’m in a maximalist phase where a chunky metal bike with lots of bolts and parts seems awesome.
More in the spirit of your ponderings, I’d also take maybe a RM Element Horst link rear on a skinny steel front end.
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Cr4w
2 years, 7 months ago
Nicolai will customize the geometry on existing designs for 750€, which all things considered isn't bad given that no other brand of their stature offers this option for FS bikes. Though I'm sure it would cost a lot more than that to have them make something fully from scratch.
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Andrew Major
2 years, 7 months ago
I can’t imagine a custom steel front end from a small builder with a larger manufacturer’s rear would be significantly less expensive than even a semi-custom Nicolai.
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Moritz Haager
2 years, 7 months ago
Why a steel front triangle rather than aluminum? I guess aluminum is a little bit harder to work with but not crazy and it would offer significant weight savings. I guess steel offers better longevity but likey geometry trends would change before your aluminum wears out.
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ackshunW
2 years, 7 months ago
Easy, because steel is real.
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fartymarty
2 years, 7 months ago
And because you can beat the hell out of it for years and it doesn't fatigue / crack like Aluminium.
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Andrew Major
2 years, 7 months ago
It’s a great question! I always to straight to steel in my mind because the small builders I would talk to work in steel.
A Frank The Welder custom aluminum front end would rock too! And as you say, should save weight without sacrificing anything for the application.
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cyclotoine
2 years, 7 months ago
You'll recall that back in the day AMP was a purveyor of crate rear ends. I have a 1993 Rocky Mountain "The Edge" (nod to U2?) in my bike cave that needs assembly. The rear end is of course aluminum Amp stays and shock. The front triangle was welded by Mr. Dekerf AFAIK. Yes it is the steel one, the '94 went to aluminum front triangles.
With the integration of todays bike I just don't see crate rear ends being a think and I don't see big manufacturers wanting anyone else to use their designs. Too many liability issues and so on these days plus they want people to buy their whole bike, not just a rear triangle.
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papa44
2 years, 7 months ago
Veering wildly off topic but I have a dekerf welded chromag and it’s stunning in both lightness and weld quality, I would absolutely ride a full boing if Chris started making them with those sweet hands of his haha
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fartymarty
2 years, 7 months ago
Chromag need to make a single pivot FS frame - K.I.S.S.
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Andrew Major
2 years, 7 months ago
I think history has demonstrated that there are three ways to build a good, reliable, steel FS bike.
Build a uni-pivot with a solid front and rear end.
Build a solid front and rear end and attach them via two links.
Build the backend around aluminum frame members. If Cotic couldn’t figure out a reasonable weight, all-steel, linkage driven single pivot it makes me think…
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papa44
2 years, 7 months ago
Agreed I think cotic probably have it nailed at this point
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Andrew Major
2 years, 7 months ago
Everyone I know with a Cotic hardtail or dually (and there are a couple or few folks now) is beyond happy with the purchase. I know they have a bit of a cultish/Chromag* following in the UK but over here I think that's a much more straight-up performance review.
____
*I feel the need to note that this isn't a dig at Chromag. They make fantastic stuff and I am not immune to their charms - heck, I love their QR's this much - it's just... well... see the Starling Fallacy.
Andrew Major
2 years, 7 months ago
Yeah, I’ve seen lots of different AMP bikes in person.
Many manufacturers don’t want to sell frame-only, never mind back ends but I can think of a few, I think, compelling reasons they should. Might write about it in the future; might not. Didn’t love-love this piece but have really enjoyed the comments.
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Tim (aka DigitBikes/DirtBaggies)
2 years, 7 months ago
Given any option, I just built this: DigitBikes
Sorry, I haven't emailed a press release (yet?).
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Andrew Major
2 years, 7 months ago
It’s tres cool for the Balfa Belair factor and very, very clean looking.
I turn wrenches part time and have to look at an endless stream of unsupported old stuff from major manufacturers, so I could never get past it he proprietary shock myself.
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Tim (aka DigitBikes/DirtBaggies)
2 years, 7 months ago
I've been a wrench since way back when, I did this in the name of reliability, serviceability and to get past some shortcomings of standard shocks.
This shock can be serviced, all the way to the oil and shims with tools you should already have, the most esoteric being a Schrader valve core remover, and the seals are all available at (good) hardware stores.
I wrote a big ol' thing about it at digitbikes.com (under the INTEGER heading). There's another even bigger write up about it on Beta.
I guess this could potentially be bad if you're currently turning wrenches for work as people might repair at home, but I doubt it will put anyone out of work. There will always be folk who don't want maintain their bikes.
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Andrew Major
2 years, 7 months ago
I checked out your Kickstarter already and I'm certainly not saying the concept isn't interesting. I see the breakdown of the tools needed to service your shock; however, I checked again and I don't see a breakdown of the individual shock components.
Re. seals, it's cool that they're readily available. What about other wear items, for example, the bushings? Are the rest of the hard parts custom made or is there overlap with existing suspension products?
I may be missing a page or some information, but it's hard to have an informed discussion without seeing a teardown.
I don't think any wrenches are currently worried about having customers looking for service; however, trying to manage expectations around products that can no longer be supported at a shop or manufacturer level sucks.
For example, I personally was very impressed with the performance of the Fox/Cannondale DYAD rear shock but I'm very glad I don't own a bike that came spec with one as factory support for hard parts lasted a couple of years at best after production ceased and there's no aftermarket replacement option for a proprietary pull shock (I mean, technically you could fit a DT Swiss EQ in there but those were only supported for a few years after Scott switched back to push shocks too).
In both cases (DYAD and EQ) a lack of seal kits wasn’t the downfall.
I'm guessing anyone who's been a wrench in these situations has an answer for the query, so I'm interested in yours.
Cheers,
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Tim (aka DigitBikes/DirtBaggies)
2 years, 7 months ago
The same concerns might present if an idler assembly wears out on a bike made by a small manufacturer.
For the first year or two Maverick made their own shock (M*Bits), then Fox took over. Before covid I was talking with some of the established suspension manufacturers and had hoped to work with the them, but because of the current supply chain delays some of them are now facing a 600 day lead time for OEM delivery. This is not a great time for them to focus on my project, and it's not smart for me to rely on that. So, rather than wait for 2 years (to possibly then learn it could be longer), I can start this by making my own shock - the parts are simpler to machine compared with an eyelet shock (or an idler sprocket). I've consulted with the earliest founders of MTB suspension, and the most respected gurus in motorcycle suspension, and since launch I've been approached by industry guys with ideas of suspension OEMs who might have some capacity.
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Andrew Major
2 years, 7 months ago
No doubt. Getting anything manufactured is tough right now. The shortage of aftermarket forks/shocks has been as crazy as chains, cassettes, etc.
Can only speak to the local experience but I wouldn’t sell a comparison to Maverick too hard. Not only were the bikes and forks shit - even for the time - but the after sale support is exactly the kind of example that informs my questions about support for a proprietary suspension system.
It’s much easier to bodge an idler than a shock body, but certainly your point is taken regarding proprietary parts on other small production frames - something that combining factory rear ends from big manufacturers with custom front triangles could help mitigate.
I’ll certainly be very interested to see a suspension teardown when you have one.
Flatted-again
2 years, 7 months ago
I’m surprised that for all the talk about the lux rear end and a custom steel front triangle that Swarf hasn’t been mentioned. Seems like other than the shipping issues, which might not be the case in Canada, itd be the way to go. Alternatively, I know of at least one person that’s mated a steel frame to their carbon rear end when there was a break. (A transition scout)
Edit: it looks like custom geo isn’t possible, nor is shipping to the US or Canada,
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Andrew Major
2 years, 7 months ago
Swarf 130 is a cool looking bike but not really what I'm getting at (and that's on me fully, as I said above - I don't love-love this piece... I would write it differently if doing it again). For me, it's the chance to get exactly what I want in a front end (full custom geo) while at the same time taking advantage of the manufacturing and engineering of larger companies for my rear suspension needs.
What I was leaning into is, what rear end would you choose | what geometry would you choose. I can have an Epic Evo with Stumpy Evo geo for example.
Anyways, as food-for-thought goes I think it did okay, but I'd approach the topic differently a second time.
Cheers!
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Flatted-again
2 years, 7 months ago
Ah, got it! It’s an interesting thought experiment. In that case probably something like a Revel ranger rear and a BTR ranger 29er front. Beyond the obvious synergy of two rangers, it gets the carbon rear, the canfield linkage, 120/115 travel, and excellent welds with a 62 degree HTA. Selecting a front is more than you asked, but how can I resist?
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Andrew Major
2 years, 7 months ago
That that sounds awesome actually!
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olaa
2 years, 7 months ago
The steel enduro Gambler at the end of this thread on Vital is a pretty neat execution of this idea: https://www.vitalmtb.com/forums/The-Hub,2/Bike-design-as-a-hobby,10880?page=2
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Andrew Major
2 years, 7 months ago
Cool find! That’s an awesome execution of the idea.
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Tim (aka DigitBikes/DirtBaggies)
2 years, 7 months ago
@Andrew Major, apparently our conversation thread closed before giving me a chance to respond. I'm not sure if that's a feature or a bug, but it seems worth looking into.
I hear you on the comparison to the Maverick, they stiffened up when you stood up which is the opposite of what I want. My point was that their shocks, which were longer lasting than the chassis', and were also serviceable (mostly) without special tools. The shocks customer support improved as the company grew, and it probably would have improved further if GT hadn't sued them out of existance with the iDrive patent.
Off the top of my head I know at least 2 places in the US who would service them, 1 in the UK, and parts were available for years (maybe they still are) through an outfit in Colorado; and I looked at the manuals online recently for inspiration for my own shock (though it didn't really provide any).
As I mention on my main page, there will be teardown videos and manuals. There's another discussion of the shock on Beta's site, and on MTBR, and to a lesser extent on PB (I've not posted the links here, because I'm not sure whether that's cool or not).
Oh, and perhaps you hadn't realized, the reason I posted this is that my bike has a "crate" rear end.
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Andrew Major
2 years, 7 months ago
Hi Tim,
Rather than being a feature or a big it’s a quirk. You just scroll up and hit reply on the last comment in the thread with a reply button and it drops your text in at the bottom of the thread.
I’ll certainly watch for the shock teardown and I have no qualms about you posting the links here. Everything I write for NSMB is intended as a conversation starter as opposed to a final word as proper organic conversations go where they may.
If I can make a recommendation it would be to include extra wear parts with the bikes (seals, bushings) even if most people won’t need them or they’ll be easy to source and have a support plan in place because salty folks like me are always going to hit on it. Not intending to be an asshat but just because I like to see the whole story.
If the shocks are easily serviceable at home that’s a huge bonus but it usually comes down to easily serviceable for whom. Certainly when your products success grows to the point of production and you’re sending out bikes to media I would love to take one apart and put it back together (and ride it too).
I’m going to leave the Maverick talk where it is if that’s cool. Some dead things are best left buried perhaps… as my friend Jac would say: 9ft deep, with a house pet buried 3ft deep above them to eliminate the effectiveness of the cadaver dogs.
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Tim (aka DigitBikes/DirtBaggies)
2 years, 7 months ago
The neat-freak in me wants to delete and repost my post things back in order, but then your reply will be out of order, and the neat-freak is freaked out by that!
Here are those links to the Beta stories about the Datum bike and the one titled "Why It’s OK That the New Digit Datum has a Proprietary Rear Shock". There's no tech in there which isn't on my page, but a Ferrentino review is a better read than my list of specs.
If anyone else reading this is interested by this bike, please check out the DigitBikes Kickstarter, it's already 57% funded in just few days and the discounts are substantial for a mUSA bike (the MSRP will necessarily be somewhere in the Reeb to Geometron range)
Have a great weekend, happy trails.
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Velocipedestrian
2 years, 7 months ago
Tim, I'm interested in your project, but please check your links, they're hitting the 404 NSMB page.
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Tim (aka DigitBikes/DirtBaggies)
2 years, 7 months ago
Thanks for your interest, and thanks for pointing this out. It turns out I need the "http://www." part.
I'm not getting Disqus notifications either, but I'll be sure to check back here periodically if you have any questions about the project. Or shoot me a message on the Kickstarter page.
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DancingWithMyself
2 years, 7 months ago
Seems you have moved on from the gram counting article you penned a few months ago? ;)
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Andrew Major
2 years, 7 months ago
HAHAHAHA. I guess I could say that a super lightweight carbon rear end on a custom steel, or custom aluminum, front end is significantly lighter than an all-steel custom production. But certainly, a carbon Hei Hei with an angleset would be a much lighter option.
When I write an editorial like this, or my Weight Is Over piece, I have two goals. The first is to entertain. The second is to inform. And I know I've done a decent job when the entertaining and informing is a two-way street. Like this piece! In fact, I think the comments are better than the article, which is always nice.
The fact is, if one of my part-time gigs wasn't writing for NSMB.com I would probably be quite content to just ride my single-speeded Walt on all my mountain bike rides without a second thought. I don't care about being first up or down the hill and it's a beautiful mountain bicycle to ride. It's all go all sort of different guises from rigid 29+ to the XC build I'm running right now, though even with a 120mm XC fork and lighter wheels, it's no featherweight.
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DancingWithMyself
2 years, 7 months ago
You didn’t need to give me that much of reply! Just kidding you. I have no interest in a bike like this, but like all your other articles, I read it, enjoyed it, and learned a lot. Well done as usual.
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Andrew Major
2 years, 7 months ago
Ha, all good. I like to make sure it’s out there so it was a good prompt.
Cheers!
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DancingWithMyself
2 years, 7 months ago
Also, I have zero envy of reviewers. I like to get my bikes dialed and then not think about them while riding. Being on different frames and components all the time sounds miserable. But, I sure do enjoy and appreciate the reviews!
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BkrAdam
2 years, 7 months ago
There are some builders working with steel offering custom geometry full suspension bikes. Marino and Terraplane are two I know of. Steel is inherently more heavy which makes it difficult to integrate more complicated suspension systems without adding weight. Maybe the benefits aren't as much for shorter travel bikes.
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Andrew Major
2 years, 7 months ago
There are infinite custom builders making full suspension. Some single pivot - like Marino or Starling - and many multi-pivot options either making everything in house like Daambuilt or Altruist, or using a really nice set of linkage plates with everything else in-house like Waltworks does with Trek Fuel or Slash rockers.
That doesn’t even dent the surface for options.
To my knowledge, no small builder is currently offering a hybrid of full custom geometry (steel, Ti, etc) bolted to a big player’s rear suspension system which should benefit from resources invested in materials, manufacturing, and suspension engineering.
Think a custom Marino front end with a Specialized Stumpy or Stumpy EVO or Enduro rear end bolted on.
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Cr4w
2 years, 7 months ago
Hang on. We're back to this? Single pivot around the BB? Really.
https://www.instagram.com/p/BmyHC-YBrIb/?utm_source=ig_web_button_share_sheet
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Andrew Major
2 years, 7 months ago
Pfffft. Check this: https://www.instagram.com/p/CFODPIBFUXX/?utm_medium=copy_link
The background is Dobermann, one of the three major branches of the Balfa tree, and dirt jump/street machines.
I’m not riding bikes that pivot around the BB (despite being attracted to the single speedability) but then that’s sort of an extreme example of the point of this piece.
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fartymarty
2 years, 7 months ago
Argh, back to URT....
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Andrew Major
2 years, 7 months ago
Rocky Mountain Pipeline Single Speed here I come! Hahahahaha
Andrew Major
2 years, 7 months ago
Have to dig up some authentic Easton RAD tubing though…
Cr4w
2 years, 7 months ago
I can accept that as a DJ/slope bike.
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fartymarty
2 years, 7 months ago
I never had the chance to ride a URT but would like to. For an XC rig it makes sense - I guess you just need to ride it like a HT on the downs.
unrelated but https://youtu.be/KkV10SouZHI is an interesting take.
Greg Bly
2 years, 7 months ago
Gave this some thought. A steel front triangle or aluminum with a straight seat tube . Two halves of plate machined for bearings and a machined center channel that mates to seat tube. Clamshell the two halves and bolt around seat tube. These are your adjustable pivot points to mate whatever rear suspension tickles your fancy. Cost for machining 4 pieces of bar stock. It could be done manually or simple CAD design. I'm guessing about 500$ for the machined parts as it's a very easy process with few cutting steps.
Cascade components ? Makes after market links for Suspension. Link mods are done with a newly married part machined by a second party.
Personally I like the idea of saving frames from going into the trash. Mate the two good halves together.
I used to own a lathe. I really wish I had space and money/ time to run a small cnc milling machine .
Yes with Renolds top notch steel tubing you can or as Andrew points out the better material stainless steel. You can make a front triangle about 4 pounds or 2 kgs no problem. Mate this to a spesh carbon fiber read end with said link mods. Weld on shock mounts and you . Spent a lot of money lol.
But it would be my custom bike . BTW is it impossible to buy rear ends from bike companies? Don't they keep spare front triangles and rears for warranty issue s or do they take apart existing frames. ?
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