Newbie Cassette Question

[Gazelain]

did you fit a new chain? If not the old chain (which will be worn, most likely) will be merrily destroying your nice new cassette. This could be what is making the noise.

If in any doubt you should always fit a new chain with a new cassette.

BTW Zaffiro tyres are good for the money, great for training etc but they are a fair bit draggier than other tyres and will likely be the limiting factor on almost any half-decent bike.

cheers

Thanks for the reply.

I didn't replace the chain to be honest. The bike is only about 3 months old, I've covered around 500 miles total on it so I assumed the chain would be absolutely fine.

Would that not be the case?

Cheers

[Brucey]

Thanks for the reply.

I didn't replace the chain to be honest. The bike is only about 3 months old, I've covered around 500 miles total on it so I assumed the chain would be absolutely fine.

Would that not be the case?

Cheers

some manufacturers fit cheap chains to new bikes; these can easily wear out completely in less than 1000 miles, and be at their service limit in half that. Best to check that the chain isn't elongated through wear. The chain should be exactly 1/2" pitch; if you measure carefully a nominally 12" length and it is more than 1/16" over, the chain ought to be replaced for sure. It isn't a bad idea to replace the chain in any event; keeping a chain and cassette together is not a bad idea either.

The other likely source of noise is that the cassette isn't mounted properly; either the lockring isn't tight or perhaps the last sprocket isn't mounted correctly (eg with mistimed splines) so it isn't clamping the other sprockets.

Various combinations of chain and sprocket work thusly;

a) New chain, new sprockets = all is sweetness and light.
b) New chain, worn sprockets = noisy running and some 'skipping' under load in the most favoured sprockets
c) Old chain, old sprockets = will probably run OK (not as smooth as it should) but the chainrings will be wearing faster than they should because of the old chain.
d) Old chain, new sprockets = noisy running and accelerated sprocket/chainring wear.

since chains are usually cheaper than cassettes, and always cheaper than chainrings, it makes sense to throw the chain away before it knackers the sprockets & chainrings. If the chain is worn less than 0.5% (i.e. less than 1/16" extension over 24 links) then a new chain will usually run on the old sprockets. Even if you get a little noise/ skipping at first (as per b) then it may not persist for too long.

cheers

[Gazelain]

Thanks for the reply.

I didn't replace the chain to be honest. The bike is only about 3 months old, I've covered around 500 miles total on it so I assumed the chain would be absolutely fine.

Would that not be the case?

Cheers

some manufacturers fit cheap chains to new bikes; these can easily wear out completely in less than 1000 miles, and be at their service limit in half that. Best to check that the chain isn't elongated through wear. The chain should be exactly 1/2" pitch; if you measure carefully a nominally 12" length and it is more than 1/16" over, the chain ought to be replaced for sure. It isn't a bad idea to replace the chain in any event; keeping a chain and cassette together is not a bad idea either.

The other likely source of noise is that the cassette isn't mounted properly; either the lockring isn't tight or perhaps the last sprocket isn't mounted correctly (eg with mistimed splines) so it isn't clamping the other sprockets.

Various combinations of chain and sprocket work thusly;

a) New chain, new sprockets = all is sweetness and light.
b) New chain, worn sprockets = noisy running and some 'skipping' under load in the most favoured sprockets
c) Old chain, old sprockets = will probably run OK (not as smooth as it should) but the chainrings will be wearing faster than they should because of the old chain.
d) Old chain, new sprockets = noisy running and accelerated sprocket/chainring wear.

since chains are usually cheaper than cassettes, and always cheaper than chainrings, it makes sense to throw the chain away before it knackers the sprockets & chainrings. If the chain is worn less than 0.5% (i.e. less than 1/16" extension over 24 links) then a new chain will usually run on the old sprockets. Even if you get a little noise/ skipping at first (as per b) then it may not persist for too long.

cheers

The chain that came on the bike (which is still on it) is a KMC Z72.

I'll see if the chain looks to have any wear/stretching.

[Samuel D]

I’m not a fan of old chains on new sprockets. (The other way around is fine unless the chain skips. I use several chains per cassette.) Even if the chain isn’t elongated by 1/16" over 12" of chain, it will still start wearing the tooth faces in the wrong place, shortening the life of the cassette. And it will cause a certain roughness of running, especially for the first couple of rides and especially in the smallest sprockets.

However, there could be something else going on. Hard to tell from here. The indexing might be slightly out because the cassette is positioned marginally farther left or right than on the old wheel. Or the cassette might not be mounted quite properly as Brucey mentioned. What “light adjustments” did you make to the derailleur? Check the B-tension adjustment keeps the upper pulley clear of the sprockets (but it usually does at the small end of the cassette, especially with cassettes like yours).

And, separately from this problem, since you’re using the same chain with a larger maximum sprocket (32T versus 28T) you need to be careful that the chain is long enough to allow the big-big gear to be engaged without wrecking things. Do this by pedalling by hand with the bicycle off the ground while changing gear, and stop at any resistance.