Cycling UK Forum

Hi forum,

I have a Brompton and have let the chain go *just* past 0.75 stretch. Should I replace it, or too far gone and I resign myself to the terminal decline? Maybe there's a way to "suck it and see" whether it's too late or caught in time?

Thanks for your help

Edward

What gearing do you have?
If it's a single cog with a hub gear, you may be ok.

If it's a derailleur, from my recent experience, you'll be needing a new set of cogs if you fit a new chain.
Take your pick:
1. Renew the chain and cassette, or just try a new chain first, but be prepared to need a cassette too.
2. Carry on regardless until you are forced to do something about it.

I assume that you are using a Park Tool chain checker? Assuming it's not yet at the 1 and it's a first offence you probably will have got away with it (that's my experience with a derailleur). Change the chain and see. Likely worst case will be the need for a new sprocket (or two if it's a six speed).

Thanks folks. How will I know if I need a new cassette? If the chain doesn't skip can I assume it's ok?

ed_b wrote:Thanks folks. How will I know if I need a new cassette? If the chain doesn't skip can I assume it's ok?

Exactly.

Try all combinations of gears, if no skipping is there when you put the power down, you're ok.
You must put the power down in each combination to be sure.

Thanks guys - sorry slow to say so, have been travelling.

If it's between the .75 and 1% then I have changed loads and been fine at that point, in fact I'm on my 4th chain on this transmission and they've all been over .75 but under 1%.

For the sake of £6 it's worth trying a new chain, I reckon it'll be reet.

Thanks for that! I bought a new chain, and it skips - especially in the smaller of the two sprockets on this 6-speed Brompton.

Can I just replace the sprockets now, or will the chainring ensure that any new chain wears too fast, so better replace that too?

I'd try the sprockets first. Chainrings wear slower as they rotate less often so you may have got away with it.

Thanks, @fatboy. Is it obvious to tell whether I've caught it in time? ie, how will I know?

It'll jump or sound noisy