Out yesterday riding (Canyon Nerve AL) and started to get a creaking noise which got worse as the ride progressed. Couldn't see anything to begin with but eventually realised that one of the rear pivot bolts had worked its way loose and had been catching the non drive side crank arm as I rode. Tightened pivot bolt back up as best I could and rode home - creaking stopped! There is now a gouge in the back of the crank, probably no more than 1-2mm deep but across the whole back face. See attached pics.
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So, does the crank need replacing or are they designed to take some damage without risk of failing?
Also, does a pivot bolt have to be put in with threadlock or should it be greased or do I just torque it back up?
Need to get it sorted quickly as I'm hoping to do Sandstone Way next week.
Thanks in advance,
Tim
Score on the crank doesn't look too bad, I'd ride with that and see. The cranks are hollow in the arm but quite beefy at that end.
Pivot bolt I'd remove, clean, clean surfaces, smear of grease and threadlock bolt to correct torque. Lazier fixes are available inc do nowt and see
Wot he /\ said.
Free weight saving!
You've got a nice stress riser there though - corrosion will get in and it'll fail at that point some unknown time in the future.
Do you feel lucky?? 🙂
Agree with the above, I've ridden deore/xt cranks with arms in worse nick than that and no problems here. Never had a pivot bolt come loose and I just use a little grease and nip them up a bit
What mildbore says.
Edit - reminds me, doing the Bash recently, pushing up the last steep bit from Watendlath, just about to hop on and fire on down one of my fave wee bits of flatout trail down to Rosthwaite, hear a bit of a clicking - Rear axle had loosened off and had worked it's way about half a thread from coming out.
Could've been messy/expensive.
Clean up the score.. Paint a bit of black hammerite on it. Just have a look every now and again..
Loctite the bolt for certain. Make sure you keep an eye on the crank - although I'd be minded to change it...
Do you have life insurance?
😉
I'd probably not worry about the crank arm [b]immediately [/b]... but perhaps if I saw a used but unscratched one on ebay I'd probably replace it as its at the point where it gets most stress. Might outlast the bike (probably will)... might not ...