29er with shortest chainstays – non custom?
2 soul QH weighs a ton – thinking more along the lines of a Cotic Soul for the 29er world (yes I know there will be the Solaris but there needs to be others) but the type of bike that can happily mix it up on the Peak or Lakes classics but is not built like a tank and still has lots of finesse.Posted 6 years agomick_rSubscriber
My homemade custom 29er runs chainstays at a smidge under 16″. Combining this with Sam’s Hummingbird fork (55mm offset) and a 70 head gives rather nice handling in my opinion (I’m 5ft 10″ so my weight isn’t too far back). It won’t suit everyone but I’d suggest people under 6ft shouldn’t flame the idea until they actually try riding one. It is just another way to get a sensible wheelbase 29er instead of the normal long stay / steep head angle route.
I can’t / don’t run a front mech. Usual setup is singlespeed but took it to the alps this summer with 5 cogs at the back and it climbed just fine (not lifting the front wheel). 2.4″ tyres and bags of mud room thanks to subtly elevated chainstays (just enough elevation to clear chain running 32:32 max ratio).
I put a big curve in the seat tube to clear the tyre but most others are using a straight tube joining the downtube ahead of the bb shell.
Starting to get a reasonable range of production models (Canfield, Kona etc mentioned above). However looking at some build photos I’m a little sceptical of some of the claimed chainstay lengths – there seems to be a lot of daylight between bb shell and tyre on some photos of bikes claiming 16.25″ stays 🙂
Will be building another next year to suit a suspension fork and maybe with regular stays (there is room to fit them with careful design and a single chainring).Posted 6 years agojamesoSubscriber
Combining this with Sam’s Hummingbird fork (55mm offset) and a 70 head gives rather nice handling in my opinion
..gives you the same front end geo as a Jones. Works very well imo.
I don’t think there’s any real need for a 29er to be any shorter than a 26″. I’ve ridden 29ers with 435-440mm rears that hop and jump (in a trail-riding way rather than DJ) better than a 26″ 425mm rear end bike. It seems like short rears are the current focus but overall balance from bb drop, front centre and bar position all add up to be more important. The Canfields aren’t measured along the stay either, it’s measured horizontally from BB to axle – I think it’s about 16.75″ measured normally and people seem to be very happy on them.
In fact a 17″ stay on a 29er with more BB drop puts your feet a bit closer (horizontally) to the rear axle than a 26″ bike with a 17″ stay.
The Kona’s not light but it seems reasonable for what it is. Most short-stay 29ers are working out at 5lbs or more partly due to the curved seat tube needing to be plain gague or the added supports needed for the offset tubes, XX44 head tubes aren’t light either. Those 2 features alone can add close to half a lb. Add in an EBB or sliders and it takes some good tubing and design to get the frame under 5lbs.Posted 6 years ago
The measurement would not be in isolation though but it is a very important measurement when taken in relation to head angle and front centre to maintain a wheelbase that is not like a barge.
Longer front centre and shorter chainstays (within reason) has got to be a good thing within a given wheelbase.Posted 6 years agoclubberMember
My Swift with 100mm Rebas has a shorter wheelbase (by about 1cm IIRC) than my inbred with 130mm Paces. Both handle very well.
And FWIW, I often think that longer stays can actually improve some aspects of handling if you get it all right together – certainly when doing really steep climbs, a longer chainstay will help prevent you wheelying the front of the bike…Posted 6 years agomick_rSubscriber
Plenty of build pics of my E stay thing on MTBR frame forum (but need to be logged into MTBR to see them). There are also a few on Retrobike but sizing went a bit screwy at first (some better ones at the bottom of page).
Apart from wanting a suspension fork at some stage, I don’t actually feel any need to make another – I’m happy that I got the geo right first time and the E stays work just fine (but I guess stays / downtube will probably crack after a few years of use). The big advantage of this set up as a prototype is that I have a full size working model with completely unhindered BB area – so can play with different chainstay shapes before committing to make anything else.
And as people have touched on above – it was designed as a “whole” bike to go with the slacker front not just a dimension in isolation.Posted 6 years agoade wardMember
Ok it’s currently a prototype
Here are some numbers
Eff TT 609
Chain stay 417-437 All measured c/c
There is another on the way from china v2 has a few differences chain stays are even shorter 407-427 but this is so I can try a belt drive. At 417
I have been riding this for the last 6 months and it climbs really well and is great on the. Single track downsides are limited ankle clearance and the bb isn’t as stiff as I would like but these have been sorted on v2 ( I hope)Posted 6 years ago
Chainstays should be measured centre to centre from BB centre to axle centre.
So, from a handling pov when you’re stood up on the pedals the actual chainstay length, which is what you’re on about above, is what matters right? But if you’re sat down then the effective (if there is such a thing) chain stay length – based on where your arse is at compared to the rear wheel axle is more important, yes?
So, for a bike where you are out of the saddle more (i.e. a singlespeed) then the actual chainstay would be most important and there is little that can be done about that given the size of wheels and the need for a bottom bracket at a sensible position. Where as for a full susser, where you might (might) be sat down more, there seems to be more opportunity to play about with things, is this right.
(I’ve been to the pub)Posted 6 years ago
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