[Bishop007]

Hi there

I was out biking yesterday, when almost home i was getting ready to climb a hill, while standing up in the pedals, suddenly the left pedal went off causing me to crash. Other than creating a rather deep cut in my knee , the thread in the crank arm is ruined. The crank XX1 has only been ridding about 100km, therefore I am quite disappointed. I have written the shop where I purchased the crank set, but no news. Do you guys think this qualify for a replacement kit? If not does anyone know where to purchase only the left crank arm?

 

[Le Duke]

eBay.


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[Bishop007]

eBay.


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Thank you for your reply, allthough I have been searching Ebay and no left crank arm has appeared. Have you actually seen a XX1 left crank arm for sale at ebay, or is it just a standard answer? BTW I have also tried google….

 

[Le Duke]

I've seen it several times, although any like-BB SRAM crank arm will work.




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[Bishop007]

Thank you

Just to be sure the q factor does not matter when speaking of the left arm, right?

This one could do just fine?
SRAM XX Left Crank Arm 175mm | eBay

 

[Slash5]

Did you install the crank or pedals or the bike shop?

http://forums.mtbr.com/general-discussion/help-xx1-crank-arm-thread-repair-907864.html

 

[Bishop007]

I installed the pedals myself, but I have done that procedure many times, and have never experienced anything like that.

Thank you for the link!

 

[Bishop007]

Ok so now after I have been licking my wounds, I was out doing a more thorough inspection of the crank arm and thread. It seems that only the last 2 mm of the threads, closest to the outer face, has been damaged. I guess the pedal must have come loose by some way, ending up only hanging by the last thread and the lastly fail.

I cleaned both the crank arm and pedal, applied some honey grease and then tried fasten the pedal, I managed to find the thread and was able to fully mount the pedal but, I guess due to the damaged thread, the pedal was not too smooth to mount. That meaning I was not able to finger tighten the pedal I had to use my allen key.

But is this safe to ride? I will off cause try to disassembly the pedal again and inspect the thread to make sure I have not ruined it all the way through, if not would you guys rely on the pedal to stay put?

 

[J.B. Weld]

But is this safe to ride? I will off cause try to disassembly the pedal again and inspect the thread to make sure I have not ruined it all the way through, if not would you guys rely on the pedal to stay put?

Maybe snap a pic of the damaged threads if you get a chance, but I think the only way you're going to find out for sure is to try it. Whatever you do make sure it is installed tight (I'd check the other one too). I've witnessed a ton of ruined crankarms and seen a lot of threads here on mtbr about pedals falling off and the #1 cause is under tightening them. Some people believe they don't need to be tight and others are afraid to damage their $400 cranks by over-tightening them, I have never personally seen crankarm threads damaged by over-tightening.

 

[Bishop007]

Thank you for reply, I really appreciate your thoughts on my problem. Below I have attached some pictures of the crank and thread. I have reassembled the pedals, really tight as you advised, although i do believe that also did that the first time. When mounting the left pedal this third time, it actually when quite smooth, not as the right one but still better than yesterday.

 

[J.B. Weld]

They don't look terrible to me, second to last pic seems about the worst. It might be worthwhile to have a shop run a tap through it, and maybe apply some low/mid strength loctite compound for good measure.

 

[Bishop007]

Thank you! I guess i will swing by the local shop. But i really do wonder how it happened, but guess i must have missed the tighten up part on the left pedal, and then it must have shaken loose. If it was a faulty crank arm i suppose the tread would have been gone all the way through...

 

[G-Choro]

Thank you! I guess i will swing by the local shop. But i really do wonder how it happened, but guess i must have missed the tighten up part on the left pedal, and then it must have shaken loose. If it was a faulty crank arm i suppose the tread would have been gone all the way through...

you could try ghetto chasing the threads by installing the pedal from the inboard side, i.e. backwards.