Chain snap

[Crankarm]

Because the cassette and chain get worn at the same rate. In my experience if you change the chain before it gets 100% worn, you can usually get away without replacing the cassette, but if you leave it too long (as I did last weekend), you'll get so much slippage with a new chain than you'll have to change the cassette too.

Which means you periodically check your chain for stretch and wear. If too worn ie more than .75 on the Park chain checker, bin and replace. This is a lot cheaper than having to replace cassettes and chain rings as well.

 

[byegad]

Because the cassette and chain get worn at the same rate. In my experience if you change the chain before it gets 100% worn, you can usually get away without replacing the cassette, but if you leave it too long (as I did last weekend), you'll get so much slippage with a new chain than you'll have to change the cassette too.

Not my experience. 2-3000 miles from a chain, replace at 0.75% worn, and three chains or more to a cassette.

 

[adds21]

Not my experience. 2-3000 miles from a chain, replace at 0.75% worn, and three chains or more to a cassette.

No, I agree with that... because you're changing your chain at 0.75. If you left it longer, you'd probably need a new cassette each time too (although my chains tend to get to 0.75 in ~1,000 miles - But that could be a number of reasons).

 

[BrumJim]

If his chain gave out, I would guess that the 0.75 limit has been exceeded.

 

[goo_mason]

Twice I've left the chains on too long and the stretch has worn the cassette so that the new chain just kept slipping. Now I'm more careful to keep an eye on the chain wear to ensure it doesn't happen again.

Chain tool - there's a great little one on my Topeak Hexus multitool, along with a bent piece of metal wire that you can hold the chain-ends together with whilst you attach the quick-link. The tool plus one of the quick-links I always carry in my saddlebag got me going again in 5 minutes after my one and only chain snap incident in 6 years of commuting.

 

[jonny jeez]

Yep,

Could be freehub is knackered. Does the cassette wobble from side to side more than a couple of mm?

Yep. It gave an occasional wobble so sounded like it too was on its way out.

Its about 15 months old and despite a lot of good housekeeping, it gets pretty poor treatment on the road and clocks up mileage in all weathers.

Both its age and mileage suggested a replacement was due.