Rear cassettes, 650 road bike

princedec
princedec Posts: 4
edited September 2008 in Workshop
I am quite new to road riding, so apologies if using the wrong terminology. I have been riding for the last year on an old principia triathlon bike which I have to stick with for another two years. I am running 650 wheels, shimano 8 speed cassette (13-26t) and double ring on the front (52t on the large ring). I am struggling to keep up with my friends on 700 wheel machines when at high speed (anything above 31mph).

Any advice on changing gearing without spending a fortune????

I have found an 11-30t cassette, does anybody whether changing from 13 to 11t would make much difference???

Thanks Dec

Comments

  • richa
    richa Posts: 1,632
    Big difference.

    What cadence are you doing? Do you know that your lack of top speed is not being able tyo turn the peddles fast enough (rather than not having sufficient power).

    At the same cadence changing from 13 to 11 is an 18% increase in spped. i.e. from 31mph to 36.6mph.

    But, where are you riding that you need to go faster than 31mph (50kph)?

    And why 11-30? If you are low geared sufficiently then 11-26 would make more sense.
    Rich
  • aracer
    aracer Posts: 1,649
    Normally I'd also be one to suggest pedalling faster, but 52/13 on a 650c bike is a fairly low top gear when trying to go over 30mph - you'd need to do 108rpm at 31mph. Trouble is, I suspect you'll find the gaps big and awkward with an 11-30. One possibility might be to mix and match - use the top two sprockets from the 11-30 (presumably 11,13 - the reason I suggest using the top two rather than just one is that usually the top two are designed to mate together)) with the 14-23 of your 13-26, assuming as is almost certainly the case that you can separate the bigger cogs. That's also assuming you can live without the 26.
  • Get a 56T ring + 11T rear cog! :wink: