Cassette gearing question

Papapete

Hi all,

Apologies in advance if i'm asking such a daft question :oops:

I'm about to get myself a new wheelset (opted for the Shimano RS30's over the Fulcrum 5's) and would like to know if I need to stick to the same cassette gear ratio that I currently have - will get LBS to fit it.

I know i need a 9 speed cassette for the 9 speed Sora shifters, but do you need to keep the same gear ratio, currently have SRAM PG95011-26 or can I opt for say a 12-25 or 12-27 (thinking Shimano Ultegra). The rear mech is Tiagra on a triple Sora front.

Thanks

topdude

Hi, not a daft question. You can have any cassette ratio you want as long as it is 9 speed.
If you have done a lot of miles you might want a new chain to go with the new cassette

Papapete

Cheers Topdude

Just had a feeling that I was being a bit thick!! :roll:

I've probably done approx 1000 miles on current chain, what's the normal lifespan? Will I get Winter out of it and possibly change in the Spring?

John.T

If you are happy with the ratios you have then stick with the same cassette but as TD says you can go with any 9sp (SRAM or Shimano). I prefer 12/27 to 12/25 as I find the 23/25 to be too close together. You only use them on the small ring when climbing so why not have the lower gears.
As for chain life I reckon to get at least 2000 miles from a chain. Measure 10 links (10") with the chain under tension. It should be less than 10.1". If more than this the chain is done for. If close I would run it for the winter with the old cassette and change both then. If you intend to change between wheelsets I would fit new cassettes to both as using one old one will accelerate wear on everything.

FSR_XC

Personally, as long as you get on with those ratios, I'd stick with the cassette and change both cassette & chain in the spring.

John.T

Its that Echo again.

Garz

What I would do is change the cassette and the chain. After the winter period is over of course.. 8)