Broken sprocket

[Steve]

Can anyone suggest how I've managed to break this sprocket (10 speed, Veloce)? It's only about 4yrs/4500 miles old so am perplexed.

[Brucey]

well my guess is that the break on the left goes through the (in a cod French accent) 'wafer-thin' region, and the break on the right was bound to happen once the other one was on its way. Maybe there was a small defect from the start.

If this hypothesis is correct you may find that the left break is slightly corroded (being older) and the right break isn't, but this could be masked by patchy chain lube so isn't to be relied upon 100%.

When regarding this design for the first time I was driven to remark that 'you wouldn't want to take any more material away' but having said this I don't recall seeing many other breakages.

cheers

[cycleruk]

Other possibility, but unlikely, is a bad gear change or jammed chain trying to cross from one cog to the next.

The break, on the right is different to the one on the left. The left appears to be a clear crack whereas the right is a "twisting" break.

[thecycleclinic]

I have a part worn 19T Veloce 10 speed sproket if that helps.

[Mick F]

........ so am perplexed.

Me too.

I had a Campag brake calliper break where the brake block fits, and I was perplexed too. Your sprocket damage is a strange defect. Do you have any thoughts on what happened, or how you found the breaks?

I have no idea about mine, I only found it whilst cleaning the bike. Was your sprocket still working?

[meic]

Could it just be that Campagnolo make junk?

[rjb]

Could it just be that Campagnolo make junk?

You must be thinking of this quote from the 1970's

"Frank Berto caustically comments that the Campagnolo Nuovo Record rear derailleur shifted poorly, but was so well constructed that it would keep on shifting exactly as poorly - forever" (taken from here - http://www.disraeligears.co.uk/Site/Cam ... le%29.html)

[Mick F]

I wonder if it's repairable - weldable?

Worth a go, but I note that "thecycleclinic" has a spare for you.

[Steve]

No idea how it happened, though like many failures it started with a clicking which I didn't get round to investigating... until too late! So must have gone in the thinner part first then finally given up with the second tear when I was climbing.

[The Mechanic]

Could it just be that Campagnolo make junk?

+1 ^^^