New 105 cassette and KMC 10L problems

Valy

Only when shifting up the cassette, the chain does not seem to engage with the teeth of 1-2 middle cogs for a few moments - the pedals spin through feels almost exactly as if it goes into a gap between the cogs which is odd cos they are both 10spd etc.

Before I had SRAM 1070 cassette and SRAM 1051 chain without any problems, got 105 just to try as it was cheaper and KMC chains cos of quick link and just for variety. I initially thought it might be the plastic spacers on the 105 cassette, so replaced them with metal ones from Ultegra cassette but to no avail. Lock ring is tightened as usual too.
Chain is the correct length, rear mech set up well and chainrings are pretty new too.

I've had problematic shifting before, but nothing like that where there is no engagement on the teeth and pedals just spin through... it's obviously not very confidence inspiring. Any advice? :shock:

nicklouse

sounds like set up/alignment.

are you sure the spacers are in the correct place/order. PS put the old ones back in.

mech hanger not bent?

should all work fine.

Valy

Yeah that's what I thought - so I readjusted the rear mech a few times - tried to have upper pulley dead on and slightly overshoot when shifting to smaller cogs and the actual shifting stayed similar overall. It's difficult to troubleshoot as it only happens sometimes. The hanger is bolted on well as is the RD and I never had that with SRAM cassette/chain. Spacers are in correct order and cogs are the right way around. By putting old ones in do you mean SRAM ones? Not sure if they are exactly the same as Shimano due to the little spacer for Shimano cassettes and no spacer for SRAM ones.

I know this is BS, but when I got the bike from new it had Ultegra cassette and a KMC 10L chain and the shifting was also quite jerky no matter how it was set up. So from my experience I have not luck with KMC chains... which is odd because everyone else likes them.

Mark__gti

Have you sorted this issue out? iv just replaced my 105 chain with a KMC chain and now im having issues with the chain jumping, im guessing i need a new cassette but its done less than 1000 miles and looks ok.

Valy

It's sort of gone, still had one jump on an upshift but mostly gone - either way don't have full confidence to upshift under load as the jerk is pretty big.

It might be that KMC chains are made to smaller tolerances than either SRAM or Shimano? It's also a fair amount louder than SRAM chains I find.