Does your Rocky Mountain have reverse chainsuck?

PB Forum :: Rocky Mountain Bikes
Does your Rocky Mountain have reverse chainsuck?
Previous Page | Next Page
Author Message
Posted: Feb 10, 2022 at 7:04 Quote
I have a 2021 Rocky Mountain Instinct a50. When in higher gears, I get a reverse chainsuck when I backpedal. I am not backpedaling much, but noticed it during normal trail riding. I was then able to replicate it in a stand. I have contacted Rocky and they said it is not a warranty issue. It seems like it is a bit severe for it to be normal and I can't imagine them designing a bike that would produce this much damage. On occasion, the chain has gotten sucked all the way below the chainstay (this is why there is a scrape across the vertical length of the chainstay).

I have taken it to at least 7 shops, including where I purchased it, and no one has been able to figure it out. Most of the mechanics said they have not seen this before, including a shops that sells many Rocky Mountain bikes. One mechanic said they have seen this, but not to this severity. If this is normal, I would not have bought the bike if I knew about it.

I am trying to gather information to see if this is a problem on other RM Instinct frames. Does anyone else has a similar problem?

Thanks

Damage from reverse chainsuck
Damage from reverse chainsuck

reverse chainsuck. The tape is there to prevent further damage. This happens when riding on the trail without the tape and without the tube wrapped around the chainstay.
reverse chainsuck

Posted: Feb 10, 2022 at 13:50 Quote
You are not alone. This isn't quite what you are describing, but maybe it will help.

https://www.pinkbike.com/forum/listcomments/?threadid=231176&pagenum=1#commentid7031705

If it is back pedalling, maybe your derailleur/hanger needs to be adjusted? You probably thought of that though.
Good luck, that looks nasty.

Posted: Feb 10, 2022 at 13:55 Quote
It's actually more common than you think, the extreme chainline of 12speed with the retention of wide/narrow rings - the chain binds and at the same time gets stuck to the chainring and will cause this.

from personal experience its only ever happend on shimano setups.

Posted: Feb 10, 2022 at 15:17 Quote
Thanks for that other thread, Bob. Yes, I've had the derailleur adjusted, clutch replaced, and then a different derailleur was tried. Unfortunately it didn't help. Rocky said I can buy a new chain stay from them, which was not the customer service I expected from them.

Posted: Feb 11, 2022 at 3:25 Quote
I would look at your rear hub, a sticky/dragging or siezed freehub would cause this.

As the wheel rolls the cassette will move with it a little with it, if this is stronger than your cage spring on your derailleur you can get slack and chain suck like this.

Posted: Mar 6, 2022 at 18:19 Quote
I had a pretty slow speed fall on my altitude back in the summer and when I was checking my bike for damage I had these exact same marks, I was wondering how it got so chewed up!

Posted: Mar 13, 2022 at 5:33 Quote
Hello i am considering buying a altitude any issues except this?

Posted: Mar 13, 2022 at 5:44 Quote
some one wrote this on another thread has anyone else experienced this?


"I only had issues with the shock eyelets, the original ones froze up almost straight away and rotated on the bolt, RM sent me the eyelets and tool for free, i bought a new shock bolt, was fine after that untill i sold it, The bikes are built well and will take any abuse you throw at them."

Posted: Jun 10, 2022 at 12:28 Quote
Late reply, but did you also consider the clutch on your Shimano derailleur?

Posted: Jun 11, 2022 at 17:31 Quote
whipsnap wrote:
Late reply, but did you also consider the clutch on your Shimano derailleur?
Ive had it pretty stiff and so far no issues

Posted: Jun 11, 2022 at 17:37 Quote
whipsnap wrote:
Late reply, but did you also consider the clutch on your Shimano derailleur?
Ive had it pretty stiff and so far no issues

Posted: Jul 2, 2022 at 7:39 Quote
Hi, I have a 2022 Instinct C70 and have a similar issue. This started at my second trail ride. I was getting chainsuck that seemed to be caused by rear drivetrain resistance when freewheeling or backpedal that causes the chain to drop at the front chain ring and also causing damage. After that ride I brought to a mechanic that I believe found the issue. After doing multiple diagnosis he showed me and explained that the cassette doesn't rotate properly when the thru-axle is properly torqued.

The problem is with the raceface rear hub. Now I'll try to explain in my non technical terms. There's a small part in the hub that maintains the proper distance between bearings. The part/ring is too narrow and bearings are too close and gets worse when wheel is torqued. He says sometimes he sees this in older bikes since the part is aluminum and when wheels get over torqued by the owner the part compresses a bit and causes the exact same issue.

I think (unsure here) for now he reversed that part to gain a few mm and its much better. They are contacting Raceface for warranty and I hope to get news in coming week. I was blessed to find this very knowledgeable mechanic at my first visit.

I'll keep all posted when I have more news. But hopefully gives you a potential solution.

Posted: Jul 22, 2022 at 12:07 Quote
Problem solved! The bike shop I bought the bike from ended making a warranty claim from Raceface. The service manager had the same issue as the OP and me with his RM. Basically the issue is that the double seal in the hub is too big (acknowledged by Raceface), puts pressure on moving parts and cassette doesn't turn properly. Solution is either get a new wheel or hub under warranty (apparently new ones are ok). Diy is either remove the double seal (not great for longevity). Or (he's done this on friends RM with same issue) with a razor blade shave of a bit of the seal so it's less thick, while it's in place as removing will break the seal likely. Hope it helps others like me.

Posted: Jul 23, 2022 at 18:07 Quote
TranceJF wrote:
Problem solved! The bike shop I bought the bike from ended making a warranty claim from Raceface. The service manager had the same issue as the OP and me with his RM. Basically the issue is that the double seal in the hub is too big (acknowledged by Raceface), puts pressure on moving parts and cassette doesn't turn properly. Solution is either get a new wheel or hub under warranty (apparently new ones are ok). Diy is either remove the double seal (not great for longevity). Or (he's done this on friends RM with same issue) with a razor blade shave of a bit of the seal so it's less thick, while it's in place as removing will break the seal likely. Hope it helps others like me.
YAY thx

Previous Page | Next Page

 
Copyright © 2000 - 2022. Pinkbike.com. All rights reserved.
dv42 0.008243
Mobile Version of Website