How Long Should Crankarms Last

So,

New singlespeed with an FSA driveset.

Bought in April, light commuting every day all on-road. Yesterday the pedal sheared out of the crank arm.

Am I being reasonable to go back to the shop and say its tat would they replace it for me?

Worth a go... a hundred quid is a hundred quid.

yep.

Who fitted the pedal? If it wasn't installed properly and you rode it loose.. well that's different.

I'd take it back, say its clearly a manufacturing fault and its not good enough.

The pedals were fitted by the shop that built the bike when I bought it. I supplied my own pedals to them and they came fitted.

They also serviced it a few months ago and didnt say anything about it.

The pedals were new and boxed direct from a mail order website.

There's probably some evidence of metal fatigue in there then. Warranty foh schnitzel.

anything potentially cranium damaging like losing a pedal mid-ride should give you righteous indignation points to play with at any shop

nothing personal - but are you a fat bastard? managed to shear through the drive side crank of a sugino rd2 going up a hill. i am a salad dodger of note.

/i am pissed. it is only 3 o'clock.

The pedals were fitted by the shop that built the bike when I bought it. I supplied my own pedals to them and they came fitted.

They also serviced it a few months ago and didnt say anything about it.

The pedals were new and boxed direct from a mail order website.

Which shop was it ?

When you say it "sheared out of the crank arm", where did it fail exactly - did the pedal axle break or the crank?

Either way, though, if all the bike has done is light commuting then it's a fitting error or manufacturing defect and I'd be hopeful that the shop should sort it out.

Cranks can last for decades in normal road use, if correctly fitted / not crashed etc.

I would say that around 50-100+ years would be fair for a properly fitted crank arm.

So, I am not a fat bastard tipping the scales at a healthy 58kg.

When i say sheared out of the crank arm the pedal axel remained intact but the threads on the inside of the crank arm were smoothed off. It didnt unscrew itself it just pulled straight out.

Shop - Velo Ecosse in Edinburgh refused to fix it, said it wasnt a fitting or manufacturing fault as then it would have sheared much earlier instead of five or six months after I bought it.

I had to go to another bike shop to get them to retap the thread and refit the pedal.

So the moral of this is -

VELO ECOSSE Edinburgh - Arseholes

Alpine Bikes Edinburgh - Angels.

Ps the second mechanic to look at it wouldnt actually take any money for the work as he said it was a quick easy fix but I should look into replacing it as soon as I copuld because he wouldnt trust it. He said it would get me home at least. 10miles is a long walk in the pissing rain.

Take Velo Ecosse to a small claim's court. That's unacceptable. If you go to citizen's advice bureau they'll tell you who to write to and help set up the paperwork. You can get a second opinion to use as evidence from the guy at Alpine Bikes.

They might try to argue that because you've modified the crank arm since the failure, there's no evidence for it.