Who’s built one? Thoughts and opinions?
I’ve never ridden one but love the look even if it sacrifices some functionality and strength. I hear people complain about flex issues in the rear while some say it’s not a problem. Most I see are shorter CS bikes so wonder how a long CS bike would do.
They look so cool! Brad’s Modern Ultimate is a rad take on the design. I bet he would be happy to share info on it if you asked. I have seen a lot of Nishiki Aliens crack at the SS/CS brace so be wary of that!
That is a beautiful bike. Would love one of those.
I don’t have a good intuition for the strength of the elevated stay. I imagine if you reinforced the BB ST area, it would have similar strength as a normal bike. Full suspensions often have a pivot were the chainstays of an E-stay bike would attach. They manage the strength by having a bulkhead in the BB-ST-DT junction:
@Meriwether has had a few:
A few production desgins:
I built an e-stay fatbike a few years ago. At the time, I was riding an ordinary, mass produced aluminum fatbike, and the handling was a bit boring. I spent a while playing around with the design, and finally realized that if I gave up on weight, I could achieve all of my other design goals: short and reasonably stiff rear end, and humongous tire clearance.
Some pictures of the result:
The chainstays are made from ‘streamline’ profile 4130 from aircraft spruce. I don’t remember exactly what size, but they have generous wall thickness. They are joined to the outside of an extra cross tube located a couple of inches above the BB shell. This cross tube is joined into the seat tube, and also to the BB with an additional tube section. Here, everything but the BB shell is in place:
Same thing with the BB shell added:
It was quite a process brazing all of these joints, but probably due to the generous wall thicknesses of all the tubes I got away with minimal distortion.
The overall geometry as designed:
The dropouts are a crude salsa alternate-style swinging drop with ~10mm of adjustment. I am running a rohloff hub substantially offset to the driveside for chain-tire clearance.
The frame has an absolutely ridiculous amount of tire clearance - I am currently running a snowshoe xxl (5.1 i think?) on a 100mm rim, but I could probably rune a true 26x5.75 if anyone made one.
- Once I gave up on weight, I was able to achieve all of my design goals. But, the complete bike weighs a bit over 40 lbs… Not the most sprightly climber.
- Definitely no issues with excessive flex. The insides of the crankarms are about 1 mm from the chainstays, and there has been very little rubbing.
- Chainstay length has quite a bit of influence on stability when climbing. With a 424 - 434mm chainstay, this thing is a handful on steeper climbs. My previous fatbike had a ~455 chainstay, and was much easier to manage on steeper climbs.
- The short back end (and short wheelbase) does make this bike extremely fun going down steeper, tighter trails. It corners better than any other fatbike I have ridden!
- I went a bit wild with this design, and made the back end as short as I possibly could. In retrospect, a more moderate chainstay length would probably ride better overall.
- Even with a 5"+ tire, soft snow is still extremely difficult. If I ever get another fatbike, I will try for a bigger diameter tire rather than pushing the width.
- I do think that e-stay bikes are good for certain applications, but (in my opinion) only where a substantially shorter chainstay is necessary. I didn’t set out to build a bike this short, but once I settled on the e-stay configuration, I got a bit carried away and pushed it as far as I could!
I’ve only ever ridden fatbikes with elevated chainstays so take this for what it’s worth…
Disclaimer: My designs are not well engineered or FEA tested. They represent what I could fabricate with the tools, knowledge, and ability I had at the time and the customers knew they were buying a prototype. Were i to re-make these I would make them a bit differently and the changes would likely result in a stronger, stiffer, and lighter frame with the help of 3D printing. Honestly, I’m not sure i’d recommend making an e-stay bike unless you really like the look and hate chainslap. Yokes of today allow the same chainstay lengths without the other issues. Other than short CS, E-stays were made mostly because of the chain suck that happened with 3x front derailleurs.
They do make a lot of sense for fatbikes, especially short chainstay fatbikes, but they can have some design challenges beyond just building them - calf clearance, flex at the BB, and cracking of course. If you ask most anybody that has lived through their heyday, many or most elevated chainstay bikes cracked and the ones that haven’t were likely babied or the riders got lucky. Not catastrophically, but cracks at the seat tube/chainstay connection. Hopefully @butchb will chime in with his experience at Co-Motion. When he saw my personal e-stay fatbike at the SLC NAHBS in 2017 he flat out said it’ll eventually fail no matter how much gusseting or internal support i added. I’ve ridden the bike since then but only ride it a handful of times a year, usually at a slow pace and on soft snow. It does seem to flex more than a double-triangle frame but it’s honestly hard to tell if it’s the 5" tires or the frame. I have built 4 others and they are still alive and well but they are not ridden on rough trails and have tires at 1-3psi providing a lot of pneumatic suspension.
The asymmetric driveside design is a bit better of a design but still cracks. It was also tried before and didn’t stick around. The first MTB with this design I’m aware of was made by Doug Bradbury out of aluminum in the late 80’s or early 90’s. The Trek Stache+ was the next one in 2015 and Salsa (i felt) copied that soon after with the Woodsmoke. The design allows super short chainstays and lots of tire clearance maintaining a Boost chainline but aren’t without issues. The guy who asked me to build him a Woodsmoke in steel cracked his Woodsmoke after a couple of years under the DS chainstay at the seat tube. I know Salsa would warranty cracked frames but they quietly exited stage left on making this bike. I was told by someone that the engineers kept adding material at the driveside chainstay/seat tube intersection because it would keep failing there in testing. My steel version is alive and well after 4 years but I’m somewhat surprised. The rider is light and smooth but he rides it fast downhill and with bikepacking gear. He has said is that it’s a little more laterally flexy than the Woodsmoke but not enough to care about it.
If you like the look of e-stay bikes you are one of a select few!
For metal bikes they are heavier because you will need to add material to try and prevent it from cracking and being too flexy. But if you like some of the things elevated stays provide then go for it!
That’s as short as it can go with that tire, wow! Isn’t the radius of that tire around 400mm?
I’ve tried 27.5 x 4.5’s and 26 x 5.1’s and the 5.1’s are way better in soft snow. I thought that the bigger diameter would help more than it did but the contact patch must not match up to the 2XL’s. I feel the 27.5 rides better overall though, just not in soft snow. However if you need studs there are options in the 27.5’s and the tires are a lot lighter when not studded so maybe you’d drop a couple of pounds.
I can just barely fit a finger between the tire and the BB shell, so it is as short as can be for that tire! I have been meaning make some longer dropout plates to try a 27.5, but I mostly use the bike for ‘walking’ the dog so it hasn’t been much of a priority.
I appreciate the perspective on the downsides of elevated stay designs, but your post does also remind me of an upside - building an e-stay bike is a great design challenge, especially because of the cracking issues! When I was thinking about this one I remember looking at pictures of one you (@Meriwether) built and thinking that it a frame like that was beyond my (very limited) fabrication skills. Going through the process of designing a frame that I thought would hold up and could actually build (and then building it) was definitely worthwhile, even though the final product is a bit weird.
I’m loving the newer generation of elevated chainstay bikes. I’d like to try building one for myself.
This is a 1990 Redline 44 that I did a restomod on. First, I sandblasted it down to white metal to check for cracks. It was in good shape for a 30 year old bike. I’m thinking it was probably built by Nishiki. It doesn’t have the RL stamped into the headtube gussets like its contemporary BMX models had.
I added a disc mount, redid all the cable routing, including internal dropper routing, and added a 44mm headtube and changed the head angle a bit. I figured it would make a cool 650B gravel bike. And maybe last a little longer since it won’t be hitting six foot hucks to flat.
It was a very enjoyable build, until I went to sell it. Got about half of what I was into it just in parts. Labor got chalked up to labor of love. After I posted it for sale, I got tons of people telling me how cool it was, but no buyers. This helped me decide building bikes needed to stay just a hobby and not a for profit operation.