Hey,
I’m in the process of designing a new touring bike for the better half and thought I’d experiment on her…could make a ride/experiment/many years of marriage joke, but will refrain as I’m new here ;).
We’ve both toured a tonne over the years and I thought I’d make an effort to build her a super comfortable and stable touring/bikepacking rig as she’s suffering a bit on my old Ti Stanton Sherpa.
But I’ve been toying with the idea of a while of going long on the rear and I see the mid-tail is starting to potentially be a thing in the bikepacking scene: (Bombtrack Beyond+ Midtail - BIKEPACKING.com; which seems pretty similar to Chris’ Midtail : Clandestine). Wouldn’t want to go this far, but serves as an example.
What are folks thoughts in regard to the effects on lateral stiffness and potential increasing fatigue on CS lengths towards 500mm? Or just on general on long CS?
I don’t think you’ll have any issues with fatigue as a longer CS will put less strain on the joints (and in general more metal = stronger). I recently made this “trad yet rad” 650B e-bike below. Since the owner carries a kid on the back, and since it already has a laid-back position, and I don’t want them popping accidental wheelies up hills, I went with 480mm chainstays.
The difficulty with going longer than that is actually buying the stays.
The stays on this are supplied at 410mm (they’re Reynolds FC1530) but you get another 20mm from the BB shell and another 75mm from those cast dropouts I’m using (which have the disk brake post mount on the LH one). You can’t go much longer than this with stock parts so will be looking for generic CrMo tubes at that point. I guess you could also offset them back onto a plate from some kind of yoke or something.
Any shorter on this bike and I also would have struggled to have fit the motor and the double kickstand in! I replaced the chainstay bridge with a plate with holes in it to mount them both onto, and it basically goes back about as far as it can to still fit the fender in.
Thanks for the input, appreciated! And nice bike! Good point on the availability. i see Reynolds stays are 450mm, combined them with a t47 bb and paragon rocker dropout gets me ball park long. Was thinking 480 for the actual build
Thanks! There are some 450mm chainstays in the Reynolds catalogue, but not in 525 which is what I usually use for the rear triangle. But it looks like Columbus have a 470 (for “fat bikes”) so there are options.
I wouldn’t expect any problems with the long stays you suggest. My touring bike has 46cm chainstays and it’s rock solid when loaded. I don’t know enough about structural mechanics to claim a longer stay makes for a stronger one, or longer lasting joints. With great lengths come great leverage…As to trail my understanding is that how one places the load on their bike can affect what trail might be better for stability/steering. The whole short trail thing seemed to be about handle bar loads as the primary location. Of course once one person of media (“of merit” was what i was first going to use but these days it’s more about hits than history) says something positive about their design, their followers will, well, follow. Then as others try out this “new thing” and find out what their grandfathers had known, 50 years ago, they start to drift in search for that “better” feel, and the cycle starts all over again. Andy.
My experience with a long chainstay touring bike has been positive. I made the chainstays 520mm long because that’s what I could fit in my frame jig. The front center is also maxed out by running a 35mm stem. The long wheelbase is great for stability and general cruising.
If you’re planning to use a rear rack and panniers, you may have to beef up the top tube, seat tube, and seat stays to resist the wagging effect.
Thanks! Looks like a cool build. Yeah, the noodlie rear worries me a little; especially
with a full food and water load for some days…i like touring in deserts so needs to be stable without becoming a tank.
No comments as the effects on stiffness from longer stays but I can say they really do work well for long distance off-road/remote touring. I have a Surly BFD with 875mm (!) stays and it handles great. Turns are slow but the increase in stability is worth it when carrying 20+L of water and a weeks worth of food. I’ve done a 200km day on that bike too. Weight matters less if ya not going up and down too many hills. And Central Aus is bloody flat I tell ya haha. For more moderate trips I’d be very curious to try stays around the 600mm mark like the new Bombtrack model you linked or the Esker Hayduke LVS.
