Mountain Bike Reviews Forum banner
1 - 19 of 19 Posts

· Registered
Joined
·
788 Posts
Discussion Starter · #1 ·
I have searched the forum and found a few old posts discussing difficulties with running the Stache as a single speed. Has anyone figured out a good solution to avoid the chain popping problems from the flexing rear end? Will a narrow wide cog make a noticeable difference?


Thanks
 

· Guest
Joined
·
5,889 Posts
How big are you? It's my understanding that the elevated chainstay chain drop issue was mostly happening with bigger guys who flex the rear end of the bike a lot more. I'm 170# and ran the first Stache 5 with elevated chainstays as single speed and never once dropped a chain.
 

· Registered
Joined
·
788 Posts
Discussion Starter · #3 ·
How big are you? It's my understanding that the elevated chainstay chain drop issue was mostly happening with bigger guys who flex the rear end of the bike a lot more. I'm 170# and ran the first Stache 5 with elevated chainstays as single speed and never once dropped a chain.
I'm 6 ft 200lbs. Yes, the problem tends to be with bigger riders getting more flex out of the frame as one would expect. I have ridden some pretty noodley ti and steel frames and not had a problem even with a much slacker chain. I'm wondering if someone had the issue and found a solution short of running a tensioner. What cog and ring do you use?

I have a 22 Rennen cog, 28 steel narrow wide ring, 9 speed chain. All new parts. With the chain tight it occasionally pops, after a few hour of riding when the chain loosens slightly the problem gets worse.
 

· Registered
Joined
·
3,555 Posts
I'm 6 ft 200lbs. Yes, the problem tends to be with bigger riders getting more flex out of the frame as one would expect. I have ridden some pretty noodley ti and steel frames and not had a problem even with a much slacker chain. I'm wondering if someone had the issue and found a solution short of running a tensioner. What cog and ring do you use?

I have a 22 Rennen cog, 28 steel narrow wide ring, 9 speed chain. All new parts. With the chain tight it occasionally pops, after a few hour of riding when the chain loosens slightly the problem gets worse.
Check your sprocket alignment, and double-check that the axle is aligned with the bottom bracket (a tape measure from the front of one dropout nut to the shell should suffice). Your chain shouldn't be noticeably loose after anything but the first ride when lubricants are displaced from the bearing surfaces; that is to say, if you start with a properly tensioned chain--~10mm of lash (vertical movement up and down) at the 'loosest' position--after a 10-20 mile ride, the lash shouldn't be noticeably worse. Unless you wind up replacing chains weekly, in which case you should be training to be an Olympic track sprinter.

A 28x22 has plenty of chain wrap, so I would suspect that it's either not tight enough--or misaligned--before assuming it is flex.

I wound up having to run a 1/8" half-link chain on my Stache to allow me to properly tension (and have breathing room for slack uptake) for my chosen sprocket combos: 32x20, 30x22. What kind of hub/axle are you using? On mine, I have a White Industries, which has a steel axle. Very 'solid' connection, and definitely contributes to drivetrain-flex related problems.
 

· Registered
Joined
·
788 Posts
Discussion Starter · #6 · (Edited)
I appreciate the thoughtful response

Check your sprocket alignment, and double-check that the axle is aligned with the bottom bracket (a tape measure from the front of one dropout nut to the shell should suffice).
All good there

Your chain shouldn't be noticeably loose after anything but the first ride when lubricants are displaced from the bearing surfaces; that is to say, if you start with a properly tensioned chain--~10mm of lash (vertical movement up and down) at the 'loosest' position--after a 10-20 mile ride, the lash shouldn't be noticeably worse. Unless you wind up replacing chains weekly, in which case you should be training to be an Olympic track sprinter.
We must have different experiences in this regard. My chain will slacken a bit after 10 - 20 hours or riding. Many years single speeding on many bikes with sliders, rockers, horizontal drop outs, ebbs, eccentric hubs, and chain tensioners.

A 28x22 has plenty of chain wrap, so I would suspect that it's either not tight enough--or misaligned--before assuming it is flex.
It is tight and the chain line is straight. The issue with the Stache is fairly well documented on other threads, but there were no remedies for it.

wound up having to run a 1/8" half-link chain on my Stache to allow me to properly tension (and have breathing room for slack uptake) for my chosen sprocket combos: 32x20, 30x22. What kind of hub/axle are you using? On mine, I have a White Industries, which has a steel axle. Very 'solid' connection, and definitely contributes to drivetrain-flex related problems.
DT 350 boost, alloy.
Oddly I have never experienced this problem even with old QR axles
 

· Registered
Joined
·
788 Posts
Discussion Starter · #7 ·
run a chain tensioner
I saw that recommended on another thread, but no luck. 8 hours today with an old Alfine tensioner and problem persisted. Possibly I could have better luck with a different tensioner, but if the chain is popping off the top of the cog where the tension is while pedaling I don't understand how having a tensioner would help. I will probably continue to experiment with the tensioner though. Shame to run one on a bike with sliding drop outs though.
 

· Community Manager at Trek
Joined
·
604 Posts
If this is for a carbon frame, those are not the best for SS, alloy is. There is more flex from the stays on the carbon model so chain popping is more common. A tensioner is the best for SS on these bikes.

Did you mess with your chainline at all, i.e. a new crank, BB, or chainring?
 

· Registered
Joined
·
788 Posts
Discussion Starter · #9 ·
If this is for a carbon frame, those are not the best for SS, alloy is. There is more flex from the stays on the carbon model so chain popping is more common. A tensioner is the best for SS on these bikes.

Did you mess with your chainline at all, i.e. a new crank, BB, or chainring?
Hey. Thanks for chiming in.

Yes, it is carbon.

Yeah, I have played a bit with the chainline. + or - a few mm of optimal either way.

The popping persists with a tensioner. I have also experimented with different amounts of tension. Definitely worse when it is slack. Seems like there really is no good way to work around the frame flex. Huge bummer. I would like the try a narrow wide cog and 10 speed chain, but hate to spend the money without hearing of other's experiences.
 

· Registered
Joined
·
322 Posts
Mitch...I'm surprised to see you post that. My experience is vastly different. Started with an aluminum Stache, and have had 2 carbon as well. All run SS. The only one I had any noticeable trouble with was the alloy one, and it honestly wasn't even a LOT of trouble, just occasional. Admittedly that is a massive sample size of...3...but along with that a few years of casual research on this very topic always gave the sense that the carbon one had less issue overall than the aluminum Stache.
 

· Registered
Joined
·
788 Posts
Discussion Starter · #11 ·
Mitch...I'm surprised to see you post that. My experience is vastly different. Started with an aluminum Stache, and have had 2 carbon as well. All run SS. The only one I had any noticeable trouble with was the alloy one, and it honestly wasn't even a LOT of trouble, just occasional. Admittedly that is a massive sample size of...3...but along with that a few years of casual research on this very topic always gave the sense that the carbon one had less issue overall than the aluminum Stache.
After reading other threads on the issue, it seems people have reported the popping with both carbon and al frames.

Also, I am able to ride this bike in such a way that the popping very rarely occurs, but if I get after it especially on a hill it happens fairly frequently.

rwitte - What size frame, how heavy are you and what cog /chain are you running?
 

· Community Manager at Trek
Joined
·
604 Posts
Mitch...I'm surprised to see you post that. My experience is vastly different. Started with an aluminum Stache, and have had 2 carbon as well. All run SS. The only one I had any noticeable trouble with was the alloy one, and it honestly wasn't even a LOT of trouble, just occasional. Admittedly that is a massive sample size of...3...but along with that a few years of casual research on this very topic always gave the sense that the carbon one had less issue overall than the aluminum Stache.
Most of the feedback from personal trial and error and other riders lead to the alloy always being the preferred SS option. However, I do think riding style mixed with components certainly play an affect on the performance.

How do you have your SStache set up now? Might be helpful for @pbasinger to get his dialed!
 

· Registered
Joined
·
322 Posts
My alloy was an 18.5, and my 2 carbons 19.5/L. I'm 5' 10" and weight varies between 165-180 lbs. I think you're hitting on the right things...set-up and component selection. I run as large a ring and cog as possible...typically I have run either 34 x 22, or 32 x 20 (oval rings.) I also think running chain tension tighter than "normal" has helped. Like I said, the popping I had on the alloy Stache wasn't at all prohibitive, it was just more than either of my carbon bikes. My alloy one was my first, so maybe I'm not properly factoring in learning the perfect set-up and components...and once I jumped to the carbon frame I had all that down. My 2018 Stache is my daily driver to this day, and I CAN get it to pop a little in just the right situation (REALLY cranking an uphill switchback.) Frankly when that happens my first thought is always "there it is, I finally broke the frame" lol!
 

· Registered
Joined
·
788 Posts
Discussion Starter · #14 ·
Most of the feedback from personal trial and error and other riders lead to the alloy always being the preferred SS option. However, I do think riding style mixed with components certainly play an affect on the performance.

How do you have your SStache set up now? Might be helpful for @pbasinger to get his dialed!

I'm not sure how helpful this picture will be. Not wanting to lose my teeth, I switched the drivetrain over to another bike which I am running with a chain tensioner until I figure out something that will work better on the Stache. I don't have closer pictures to view. I recently got a narrow wide cog and will be trying that with a 10 speed chain. I also just tracked down a pair of discos from a friend at Trek that I hope to use soon.

I have 20 plus years working in shops and for a few different manufacturers, so I understand chainline and how to tighten my axle, etc. If I didn't love the way this bike rides so much I would just give up on it, but I guess I will throw some more $ and time into trying to make it work.

I will update with more pictures and experiences after trying the narrow wide this weekend.
 

· Registered
Joined
·
322 Posts
pbasinger...just looking at that pic, I'd say way too much slack in that chain. Yeah, I'm aware that's how chains on SS usually look...doesn't need to be crazy tight. My point is that right, wrong, or indifferent, I think the chain tension on the Stache DOES need to be almost crazy tight. If not, there will be more popping. On my ovals, I set it up to where the highest chain tension point...frankly feels like it's too much. Will that stress the crap out of the frame? I don't discount that possibility, hence my comment earlier about thinking I've finally broke it on the rare occasion I do get a pop.
 

· Registered
Joined
·
788 Posts
Discussion Starter · #17 · (Edited)
I tried an Absolute Black cog, 10 speed chain, narrow wide chainring. When the tension was really high it actually held on pretty well and never popped. I could still feel and hear it start to grind on hard climbs like it wanted to jump off the cog as the frame flexed. Unfortunately it required the chain to be so tight it just felt wrong causing the chain to bind a bit on the freehub and making it a real pain in the ass to put the axel in.

I tried running some old Discos thinking that may make a little difference to keep the chain on if it did flex enough to pop off, but I don't think they did anything to really help the situation.

I found myself riding in such a way to avoid really cranking and flexing the frame, so I gave up and tracked down another traditional frame that works just as one would expect. I wish I could have found good solution, but for bigger riders it's just not a good single speed frame in my opinion.




Discos


Chain tension - This unfortunately doesn't adequately show how tight it really was, but it was pretty snug. I tightened its down even more than this eventually.

 

· Registered
Joined
·
183 Posts
My Stache never does this popping issue that I have heard about. I run 30x20 gearing with a pretty beefy chain, like something between a 1 speed and 8 sped chain. I have the alloy model. I am a light rider. I also use the problem solver zinger for SS on an XD driver.
 

· Registered
Joined
·
867 Posts
Check your sprocket alignment, and double-check that the axle is aligned with the bottom bracket (a tape measure from the front of one dropout nut to the shell should suffice).
Hey, this was helpful! After riding my Stache (carbon) geared for a few years, I set it up single speed this year. It's been working pretty well but I certainly do get the occasional chain pop when maxing out on steep climbs. I ran across this note, pulled a tape... and it turns out my wheel is not dished correctly and that as a result I had set it up crooked in the frame. I haven't had a chance to re-dish the wheel yet, but certainly hopeful that that solves the problem.
 
1 - 19 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top