Cassette gearing question

Papapete Posts: 133
edited November 2009 in Road beginners
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.



  • topdude
    topdude Posts: 1,557
    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 :D
    He is not the messiah, he is a very naughty boy !!
  • Papapete
    Papapete Posts: 133
    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
    John.T Posts: 3,698
    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
    FSR_XC Posts: 2,258
    Personally, as long as you get on with those ratios, I'd stick with the cassette and change both cassette & chain in the spring.
    Stumpjumper FSR 09/10 Pro Carbon, Genesis Vapour CX20 ('17)Carbon, Rose Xeon CW3000 '14, Raleigh R50
  • John.T
    John.T Posts: 3,698
    Its that Echo again. :lol:
  • Garz
    Garz Posts: 1,155
    What I would do is change the cassette and the chain. After the winter period is over of course.. 8)