New chain, now a bit of slip.

Koncordski

Having got fed up with the state of my original chain on the Trek 1.1 I decided to change. Hung up the old chain on a nail and measured out the new one as per helpful forum threads on here.

New chain is a KMC 8 Speed and fitted using a removable quick-link. One thing i noticed when measuring the chains is that the old one had a reasonable amount of stretch on it. Ended up counting the links to make sure it was correct for length and fitted.

Awesome smooth shifting again but if I stand up on the pedals on an uphill I now get the occasional chain slip, it feels like it's jumping a single tooth on the rear. I'm thinking the old chain may have worn down the teeth perhaps but the bike has only done about 1200 miles?

Is it because I'm using a KMC chain on a Shimano cassette? It's fine putting the power down 90% of the time just going up hill standing on the pedals that does it.

wgwarburton

Hi,
Sounds like a new chain on a worn sprocket. It may well "bed in" quite quickly.

Can you pin it down to a particular chainring or sprocket at the back (most likely the combination you use most, or the one you use most cranking uphill or accelerating)?

Cheers,
W.

davis

Yup. You've probably just worn a sprocket a bit. At 1200 miles for a new chain I'd probably just continue riding it without putting too much pressure on the cranks, and it'll probably settle down fairly soon.

Maybe rotate those two chains every 1000miles until your cassette's toast.

Koncordski

Sounds as though it needs to learn to play with the old cassette then, I first noticed going up the 'ramp' to westferry circus roundabout so didn't have time to try different rear cogs. I'll give it a few laps tonight and try and isolate the problem. Love how smooth the shifts are now, all the black gunge was scrubbed off before the new chain went on. I reckon it gives you a 2mph boost (in your head) on a shiny bike. 8)

Koncordski

Ok having played around with it on a few rides I'm convinced that the cassette is toast. Based on the amount of stretch on the original chain it makes sense. I'm going to buy a new cassette so as not to wreck the new chain on worn sprockets but was thinking of going from a 12-25 to a 12-21. It's only 4 teeth smaller so do i need to bother shortening the chain?

The Rookie

You may not want to bother, but you could loose 4 links and save some weight!

You'll need to tweak the B-stop on the rear mech for best shifting.

Simon