Rail - creaking crank arms...

[UVRail]

Hi

I've done about 3000 miles on my Rail... after around 1500 the bike was suffering major creaking. I followed various Youtube videos, took the stem / forks etc. apart, cleaned and regreased, took the crank arms off, cleaned, serviced the pedals etc., checked the torque on the major bolds / pivots / motor retaining rink and tightened... all good - creaking completely gone.

Apart 500 miles later, the creaking returned albeit less severe, I only tightened the bolts on the crankarms this time, back to the correct torque. Again, creaking gone.

Now it's returned and seems to be coming from.. the crank arms. Anyone have any ideas on a more permanent fix? I'm thinking:

1. Upgrade / change the bolts to something that will stay tight at the correct torque (and suggestions on products?)
2. Upgrade the crankarms to something more precisely engineered / higher quality
3. Put loctite on the bolts and retighten (any suggestion on products or is Loctite the best choice?)
4. Remove crank arms, put more grease on the motor splines, then reattach (any suggestions on specific types of grease / agent that might work well)?
5. something else?

Any suggestions gratefully received!

Many thanks,

UV

 

[Doug Stampfer]

I just gave up on chasing creaks on mine & chose option 5 - listen to music through earplugs. Sorry not much help.

 

[aviserated]

Noises are so hard to pin point. Have you tried greasing crank arms? Some replace the main lower rear swing arm to frame with new bearing Trek kit.599909

 

[Orangie]

Main pivot and motor mount brackets shut mine right up

 

[UVRail]

Thanks all
Am going to try some Copaslip on the crank arms, maybe with some Loctite on the bolts. I recently retorques the main pivot and all the motor brackets, but will take another look.
Any other ideas very welcome!
Cheers,
UV

 

[Mitch@Trek]

Thanks all
Am going to try some Copaslip on the crank arms, maybe with some Loctite on the bolts. I recently retorques the main pivot and all the motor brackets, but will take another look.
Any other ideas very welcome!
Cheers,
UV

Blue threadlocker/loctite would be your best option, just an FYI. I've seen folks use red which isn't a good choice on something that you want to be able to remove without a fight.

Also, check your chainring interface - clean it up and apply grease which often helps!

 

[aviserated]

What is chainring interface? Is that the nut that tightens on chainring. I have seen YouTube video showing chainring nut may become loose causing noise. Would blue loctite work here also?

 

[Mitch@Trek]

What is chainring interface? Is that the nut that tightens on chainring. I have seen YouTube video showing chainring nut may become loose causing noise. Would blue loctite work here also?

The location where the chainring and cranks touch. Some are through bolts and others are a spider (i.e. Raceface and SRAM). Grease in these locations typically resolves creaks. You can use blue loctite on the bolts too, but sometimes a little dab of grease is all you need.

 

[Mohawk3a]

What is chainring interface? Is that the nut that tightens on chainring. I have seen YouTube video showing chainring nut may become loose causing noise. Would blue loctite work here also?

I was chasing creaks on mine for awhile. Greased every pivot with no success. Noises went away after I tightened that “chain ring nut”. I found that it often comes loose. If you ride with the chainring loose you can strip that nut, I’ve done that too.

 

[ezliven]

My 2020 Rail 9.7 had a creaking noise for some time. The creaking was minor at first but got progressively worse to the point others riding near me could hear it. I had taken all the pivot points apart and cleaned and retorqued them and cleaned seat post but still did not fix the creaking noise. Finally the only thing left was the motor mounting. I had noticed while holding the brake and stepping on the crank that the motor had a slight movement to it. I removed the motor and found the bolts for the motor mounting bracket were loose and one had broken off. I was able to remove the broken bolt. For some reason Bosch had installed them with tamper proof bolt heads and did not have any lock-tite on them. I removed the other 3 loose bolts and installed 4 new M5-18 X 16mm bolts with regular allen heads. Installed them with lock-tite blue and torqued them to 6 nm. Reinstalled them motor and have 2 rides for 40 miles and not more creaking. Bracket shown in the attachment.

 

[Stihldog]

Can’t se the pic but I get the idea. After all that maintenance it’s easy to overlook the motor mount brackets.

Here’s a link to some more posts on this subject.

Trek Rail 9.7 Motor Mount Part Number

Hi, Looking for the part number of left and right motor mount brackets for my Rail. The local dealer is moving slow on finding the part number.

www.emtbforums.com

My Rail 9.7 did not have this issue with the brackets but other riders have. I had my suspension bearings replaced shortly after I purchased the 2020 Rail. I also regularly grease the main pivot bolt.