KMC chains on part-worn cassette

goosey

I've tried fitting KMC 9.93 chains on two bikes. Both were fitted with Sram cassettes and had previously been run with a Sram chain from new, so were not obviously worn out. Both the new chains skipped on the cassettes.
Is this something to do with KMC chains, Sram cassettes or both? I don't want to have to fit a new cassette every time I change a chain...

nicklouse

sounds like the cassettes were more worn than you thought.

goosey

Could be - just seems a coincidence that it happens on 2 bikes at the same time. Neither chain was more than 0.75% stretched and I'd never had issues with using Sram chains on part-worn cassettes. Never tried KMC before.

oodboo

This is why I wont change anything until the groupset is on it's last legs. Then change the lot in one go. I've never had a groupset working properly with an old/new mix. Just upgraded to 1x10 xt on my bike so will buy a chain, cassette and chainring over time then replace them all in one go when my gears start failing me.

The Spiderman

I have an XT cassette running on its third chain,this time a KMC X9 after 2 SRAM PC991s.It works fine,but I use a chain checker and change chains as soon as they hit 0.75.

cycleclinic

I use these chain in the shop and I often fit them to a "worn cassete" with no issues even 500 miles on.

My rules of thumb are if the bike is brought in and the chain has just reached 0.75% and the it the first chain on the bike then a new chain on the old cassette should be O.K so long as the cassette looks fine. By changing the cassette at 0.75% wear you should get 4 chains or so out of a decent cassette.

If the bike has a chain that is passed 1% wear the cassette has probably worn and while a new chain may work on the old cassette it may not work for long before slipping starts so a new cassette will be fitted.

If the customer indicated that cassette is on its third chain I will not chance it and replace he cassette. It seems to work.

bobgfish

I find that sometimes it will skip on just one cog or so. If this is the case I use it for a week or two on other cogs and generally find that it then setlles down a bit and stops skipping. I did this on my road bike over the winter. I knew my cassette was toast but wanted to wait until spring to dump chain and cassette together.

goosey

Well, here's a thing. Fitted a bike with a BRAND NEW Sram cassette and a KMC chain, and that skipped too!

cooldad

Your indexing is probably out.

mrmonkfinger

I seriously doubt there is anything incompatible about KMC chains and SRAM cassettes.

Last time I changed chain, it was the third chain on that cassette, skipped in the most common (middle) cog, so that was time for a new cassette.