just on the onone site and theyve got 3 different 9 speed sram chains – the 951 and 971 are £10 each and the 991 is £15. which do you recommend? also is it true you always need a new cassette with a new chain? mine looks in ok nick so dont want to replace it unless i have to

they are all similar but slightly lighter as they get more expensive.
Whether you need a new cassette depends on how far gone your old chain was before you replaced it. Did you measure it with a chain tool or just decide to replace it?

not measured it but i just wanted to replace it as its had a rough winter. i cant clean it up and it has rust spots here and there.

if you can borrow a chain measure tool and it’s 0.75 or less you can get away with using the cassette for longer, if it drops in as a 1.0 then it’s worth changing the cassette but it’s quite cheap for nine speed so shouldn’t be a problem

The PC951 isn’t nickel plated, the 971 has nickel plated outer plates, the 991 inner and outer, basically means you’ll be able to get them shiny again once they’ve been used, as you’re obviously bothered by such things I’d get the 991.

I’d also recommend not getting rid of your old chain – if you put the new one on and it skips (pretty likely if you ride a lot in winter) then you have the option to put your old one back on and run it into the ground.

I’m currently doing just that after I didn’t change a chain in time, it’s eeked another year out of a cassette, although the shifting is getting sloppy now.

Cheers, 991 it is then. Never replaced a chain myself. Tried it once on my old singlespeed and I made a right pigs ear and ended up at my lbs.

just put my old chain back on,cassette looks ok but shafted,new cassette ordered from On-One sram 980 £29.note to self check chain every month or so 🙄

Buy cheap, replace often.

Buy cheap, replace often.

Or buy expensive, entirely obliterate before replacement. Cheaper in the long run I reckon.

Not when you end up having to replace your chainring and cassette.