Having just changed my chain, not because it needed it really, it had only just about reached the 0.7 mark on my measuring thing… the chain is starting to slip on the cassette under load, but the unusual thing is that when it slips, it changes into the next gear, and then slips back again. I’m pretty sure when they have needed changing in the past they haven’t done this and just remained in the same gear. is this gear adjustment issues or time for a new cassette? thanks.

I’d put a new cable on it, and set up the gears. If that doesn’t work then new cassette.

Either really – I would at least clean and lube the cables and setup the rear as best you can (free) and if it still jumps then try a new cassette 🙂

Thanks guys, I changed the cable not long ago, and cleaned and lubed it when I changed the chain. I’ll have another tinker but sounds like its the cassette. If that’s the case I think I’ll put the old chain back and get a bit more life out of both first. Thanks.

yup good idea although your front rings may wear a bit more rapidly although if its below .75% may not be too bad 🙂 Also if it stops jumping when you have put the old chain back on then you have your answer 🙂

When you changed the cable did you do the outer, or just the inner? I had a similar problem caused by my new inner being fouled by a knackered section of outer.
If you put your old chain back on and it continues then this gets my vote

Thanks Sweepy, if it still jumps with the old chain then i’ll try that.