New chain

[Ajax Bay]

If you put a new chain on an old cassette, the 'handshake' is slightly off. It will mesh after a few miles of riding, the best way to prevent or at least reduce this type of chain skipping, is to replace the cassette and chain together.

First part is complete BS (but you keep on asserting this, @Racing roadkill , thread after chain thread, despite repeated articulated dissent). If you've let the chain go too long that's it and the worn cassette will not work with a new chain. A "few miles of riding" will not "mesh" the new chain/old cassette combo.
However, if the new chain is skating on the old cassette (and you've only replaced the chain because it had elongated close to 0.75%), then it's probably worth putting the old chain back on and 'using it up' - get another 1000 miles. However, gleaning a glimmer of positive from your second part, then replace both chain and cassette together: spookily the 'handshake' is firm from the first turn of the pedals.

 

[johnnyb47]

Sorry to hijack this thread but i seem to have a similar problem ( i think ) with a worn out chain. Last night i bought a new set of wheels and cassette and the drive chain seems to "chatter" quite loud on the smallest sprocket of the cassette. I have friction shifters and the derailleur is set up perfectly but the chain is still noisy. I don't have chain tool ,to measure the tolerance but tonight after coming back from my evening ride I've noticed if i slowly turn the chain backwards it seems to slowly ride up between the teeth of the sprocket and then snaps back into then. To me it looks like that the chain is slightly stretched and won't sit on the chain ring properly. Could this be the case?
All the best
Johnny

 

[Ajax Bay]

the drive chain seems to "chatter" quite loud on the smallest sprocket of the cassette. . . . I've noticed if i slowly turn the chain backwards it seems to slowly ride up between the teeth of the sprocket and then snaps back into then. To me it looks like that the chain is slightly stretched and won't sit on the chain ring properly. Could this be the case?

We (I) need to understand what is causing the 'chatter'. The smallest sprocket of the new (to you) cassette has probably had relatively little wear so if your chain is getting on a bit and elongated beyond 100.75%, quite possible it's OK with the previous wheel/cassette which has worn with it and maybe also with the new cassette sprockets which have had significant wear. Do you get 'chatter' with the largest sprocket when putting the power down on a hill? I'd describe the symptom of a chain too long to work as a sudden give/lurch as the chain skates over the sprocket teeth, and then grips, and then doesn't, and this is best tested on a safe road slightly uphill and putting power on each sprocket in turn. You'll soon know. An elongated chain will not have problems sitting on a chainwheel and you cannot see by 'looking' ("To me it looks like") whether the chain is elongated - you need to measure it: 10.05" for 10 links - happiness, but note to replace in the next 300 miles. 10.075" - replace immediately. More? Carry on using it on the cassette it's been on and replace both when misbehaviour starts.
HTH.

 

[johnnyb47]

I fitted a new chain tonight. £3.50 from wilkos, .
It was quite surprising to note how much the old one had stretched when it was laid side by side with the new one. Overall i would say the old one had stretched by about 1cm over its length. The new chain has made the bike feel silky smooth on the gears and pedal action. Well worth changing for ten minutes it took and the paltry cost of £3.50 :-)