Lifeboy123 Posts: 213
edited August 2010 in Road beginners
I am have a SRAM 50/34 front cassette and Shimano 12-25 rear.

I am looking to change the 10 cassette rear to either a 11-23 or 12-27 which I am led to believe are both compatible, and would like some advice on which one to choose and what make or should I just bite the bullet and change the front to 53/39?

I know it is advisable to purchase a new chain to take up the difference but will these be compitable with my front and rear deraillers and what is the best chain to get ?

I would expect the 11-27 will give me a wider spread of gears but I have read reports that there is too much wide a range between the gears with this size of cassette, has anyone experienced this ?


  • Mister W
    Mister W Posts: 791
    From reading between the lines I'm assuming you want a bigger top gear (the 12-27 being a typo?). How're you with the low gears? Do you struggle on hills or are you pretty strong and get up them comfortably?

    If you're good on the hills then an 11-23 would be your best option. It means you'll have close ratios all the way through the range. If you aren't so good then go for some lower gears with the 11-27 and live with the bigger gaps. They aren't massively big and you should quickly get used to them.

    Unless your existing chain is fairly new I would buy a new one to go with a new cassette. I prefer KMC chains. I generally buy their cheaper 10 speed chains and replace them regularly.
  • thel33ter
    thel33ter Posts: 2,684
    If you are spinning out too much get the 11-23, or the 53-39, which is more expensive but makes more of a difference.

    All 10sp chains will work, but I can't reccomend as I don't have 10sp.

    As for 11-27 having big gaps, this is nonsense IMHO. My 8sp cassette goes from 11-26 and I don't find the gaps to be a problem, I prefer feeling like the differences between gears.
    And now you know, and knowing is half the battle
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  • rake
    rake Posts: 3,204
    it isnt nonsense. i like close ratios. its your choice. i couldnt be without my 16 t. :wink:
  • softlad
    softlad Posts: 3,513
    technically, you only have a 'cassette' on the rear - not the front...
  • rjh299
    rjh299 Posts: 721
    Not sure what you're actually after. Higher gearing i think? If you've got 50x34 and 12-25 and considering getting a 53x39 then why would you want a 11-27? If you want an 11 sprocket why not get a 11-25 and not worry about 'big' jumps between swifts.
    Derailleurs will be fine whatever you decide to do but might need some adjusting.