Chain Ring bolt stripped. Creaking noises. Recommendations?

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Lightweenie
Posts: 163
Joined: Sun Aug 03, 2014 1:00 pm

by Lightweenie

I have been riding a power2max with 3D24 crank arms and Praxis Buzz chainrings for about two months now. It was delivered with rotor aluminum bolts, that are speced for 7-8Nm and come with some sort of loctite on the threads.

Ever since I assembled the chainrings for the first time - dry and at 7Nm - I am having a terrible creaking while pedalling. After a couple of rides I tightened them to 8Nm - still dry - and the creacking became a bit better but didn't subside. Also it got a bit quieter during the ride, only to be back at full volume at the start of the next ride. I then removed all bolts, cleaned the loctite thing off, applied grease both on the threads and outers of the bolts and reassembled at 8Nm. Creacking still there but much more silent, and even stopped completely towards the end of rides, but was always there at the beginning of rides. So today in desperation I decided that I maybe should try to torque it a bit above specs at 9Nm, which resulted in breaking one bolt.

Any ideas what causes the creaking problem? When I removed the bolts in order to apply grease i noticed that the "nut part" of the bolt had made a tiny groove on the back of the head of the "front" part of the bolt - I hope this description makes sense. So I suspect that somehow the spider and rings are a tiny bit thinner than what the bolts are speced for which results in the front and rear of the bolts tightening into themselves instead of tightening the rings. Is that possible?

Since I now have to replace my bolts anyways, do you have some recommendation for other bolts that are easier to make/keep quiet?

by Weenie


basilic
Posts: 671
Joined: Wed Jan 05, 2011 8:05 am
Location: Geneva, Switzerland

by basilic

No idea what is going on with your setup, but possibly something (holes in chainrings? nuts?) is slightly out of spec. I would just buy different bolts, any brand at random, and try that.
Also, if the BB bearings are shot they might creak. But greasing the bolts wouldn't change that.
Good luck

bilwit
Posts: 751
Joined: Sun Apr 03, 2016 5:49 am
Location: Seattle, WA

by bilwit

just put a set of TruVativ Steel chainring bolts on my chainrings, dunno if they would help but might be worth a look (both sides are hex, lot more convenient than the stupid Shimano ones that always get stripped)
Last edited by bilwit on Fri Sep 08, 2017 7:55 pm, edited 1 time in total.

ArtV
Posts: 12
Joined: Tue Mar 01, 2016 3:23 am

by ArtV

Lightweenie wrote:I have been riding a power2max with 3D24 crank arms and Praxis Buzz chainrings for about two months now. It was delivered with rotor aluminum bolts, that are speced for 7-8Nm and come with some sort of loctite on the threads.

Ever since I assembled the chainrings for the first time - dry and at 7Nm - I am having a terrible creaking while pedalling. After a couple of rides I tightened them to 8Nm - still dry - and the creacking became a bit better but didn't subside. Also it got a bit quieter during the ride, only to be back at full volume at the start of the next ride. I then removed all bolts, cleaned the loctite thing off, applied grease both on the threads and outers of the bolts and reassembled at 8Nm. Creacking still there but much more silent, and even stopped completely towards the end of rides, but was always there at the beginning of rides. So today in desperation I decided that I maybe should try to torque it a bit above specs at 9Nm, which resulted in breaking one bolt.

Any ideas what causes the creaking problem? When I removed the bolts in order to apply grease i noticed that the "nut part" of the bolt had made a tiny groove on the back of the head of the "front" part of the bolt - I hope this description makes sense. So I suspect that somehow the spider and rings are a tiny bit thinner than what the bolts are speced for which results in the front and rear of the bolts tightening into themselves instead of tightening the rings. Is that possible?

Since I now have to replace my bolts anyways, do you have some recommendation for other bolts that are easier to make/keep quiet?


My power2max with 3D24 crank arms and Praxis chainrings (not Buzz) came with Praxis bolts and have been silent both with and without grease.

ArtV

Geoff
Posts: 5137
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Chainring bolts, like pedals, require anti-seize compound, not grease.

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Lightweenie
Posts: 163
Joined: Sun Aug 03, 2014 1:00 pm

by Lightweenie

Thanks a lot for all the replies.

@basilic: The BB-bearings are quite new and definitely fine and smooth. Since the problem started when I replaced the shimano crankset with the rotor/p2max/praxis one I am quite sure the problem is somewhere there.

@bilwit, @ArtV: Steel or praxis own bolts sounds like a good idea!

For now I replaced the bolts with what my lbs had in stock, some aluminum FSA bolts with torx on one side. I measured the female parts and they are 0.7mm shorter which means that even if the rotor bolts tightened against each other, this shouldn't be an issue anymore. Also they are speced for 12Nm! Given the reduced length and that I tightened them to 11Nm I was quite confident about them - however the creaking is still there. I tried some one leg drills to notice that it is there when pedalling with only the right foot but not when only with the left. It could be possible that the creacking also comes from the spider/cranks assembly but it would be quite strange - since the noise changes each time i fiddle with the bolts...

Attermann
Posts: 247
Joined: Sun Jan 05, 2014 11:04 pm
Location: Denmark

by Attermann

maybe you need to take the right pedal off and grease the threads a bit.

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Lightweenie
Posts: 163
Joined: Sun Aug 03, 2014 1:00 pm

by Lightweenie

@Attermann, thanks a lot for the suggestion, as the pedals were also attached to the old crankset I didn't think about them being a possible issue. I cleaned and regreased the threads of the right pedal and the creaking seems to have subsided. I say seems because due to bad weather I could not test it outside but only on the trainer - but I am optimistic that it will be silent outside as well.

by Weenie


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