Mountain Biking - Today's Carnage: Taco'd Chainring

Don't ignore that missing chainring bolt or those annoying creaking sounds coming from your crank. I did, and now i'll be stuck on the road bike for a while....

http://i13.tinypic.com/42ieftg.jpg

http://i17.tinypic.com/2a77oxx.jpg

Ouch. Looks like it scratched your frame too.

Wow, thats a nasty one! Hope you had clipless so your thigh didn't fall into that one.

Are those aluminum chainring bolts? ....on a single speed?!? :eek:

You must really like living life on the edge. ;)

Are those aluminum chainring bolts? ....on a single speed?!? :eek:

You must really like living life on the edge. ;)

I'm just cheap, and too lazy to use loctite. lol

Are those aluminum chainring bolts? ....on a single speed?!? :eek:

You must really like living life on the edge. ;)

Wow..I must as well. I have never had an issue with mine.

How, what?!?! How does that happen?

Jebus. Send that pic to Surly.

That's what you get for rockin' a red crankset.


Edit: I don't mean that Surly is responsible for this, that's obviously way outside spec - but if I ran a company like that, I'd want to see my product brutalized.

Edit 2: Wait, what's the problem with aluminum chainring bolts on an SS, and can I assume the problem extends to fixies?

Are those aluminum chainring bolts? ....on a single speed?!? :eek:

And there is something wrong with this? I use alu chainring bolts on my SS as well as my fixie...

And there is something wrong with this? I use alu chainring bolts on my SS as well as my fixie...

Yes. Aluminum chainring bolts are not even half the strength of Cr-mo bolts. If one should snap, the other four (or three) will usually fail soon afterwards, resulting in the damage shown by the OP.

It's not a bad idea to inspect them freqently and carry a spare.

so... are ya gonna get to the grit of the story?? tell us your adventure!!!

so... are ya gonna get to the grit of the story?? tell us your adventure!!!

Unfortunately, there is no cool story to tell. I was climbing a steep hill, then I heard a snap.

And the bolts didnt break, they got loose. It's my own fault for not checking them, really.

You got some thing caught in the chain probably, which increased the chain tension considerably. This probably would not have occured if there was a rear derailleur on the bike to provide more chain.

damn, did the same thing on my ss during a race last season, it sucked, had to run the last mile

Yes. Aluminum chainring bolts are not even half the strength of Cr-mo bolts. If one should snap, the other four (or three) will usually fail soon afterwards, resulting in the damage shown by the OP.

It's not a bad idea to inspect them freqently and carry a spare.

Since when?

Out of all my years running aluminum chain ring bolts, I've only had 2 break and that was due to operator error(Accidently overtightened.)


You got some thing caught in the chain probably, which increased the chain tension considerably. This probably would not have occured if there was a rear derailleur on the bike to provide more chain.

If it had a deraillieur and it picked up something it likely would have caught the deraillieur, breaking off the deraillieur and deraillieur hanger, causing it to go into the spokes and breaking spokes. It can happen, but if you run proper chain tension(Up to 6mm of play in chain), nothing will hurt it.


As for ponchotempest, run all of the chain ring bolts next time, and I suggest looking for a bashring as well especially in NJ, a bent chain ring will bring your ride to an abrupt stop.

Oohhh. That looks nasty. Glad your alright.

Unfortunately, there is no cool story to tell. I was climbing a steep hill, then I heard a snap.

And the bolts didnt break, they got loose. It's my own fault for not checking them, really.

I wouldn't blame the bolts at all. The crank arm broke at the lower bolt hole for the inner ring. The crank you were using probably wasn't a good choice for single speed work since each arm was weakened by that lower mounting hold. In a derailered bike, this probably would have never been a problem because the tension on the crank is lowered by the derailer.

One question I have is were you using only 3 bolts? If you were, you were increasing the stress on the those three arms tremendously and that particular crank was destined to fail.