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Cassette size??


Getting the SRAM Force TT Groupset. Not sure on cassete size. There is 11-23, 11-25, 11-26,11-35,12-25,12-27.?????

I currently do Olympic bike leg in about 1.15 and middle distance in 3hrs on a compact ultegra, I think that's an 11-23.

This bike will take me to ironman(hopefully)

Any advice appreciated.


  • shadowone1shadowone1 Posts: 1,408
    depends on the event mate.

    11-23 for fast and not so hilly. 12-25 for the normal and maybe a 11-26 for undulating but fast??

    I have an 12-25 and 11-26, they get swapped depending on what tri I am doing. Not strong enough for 11-23.....
  • jamewahjamewah Posts: 113
    Depends on the size of your chainrings too,
    For example, My bike came standard ultegra chainset with a 53/39, and a 12/25
    This was fine for Flat / undulating and even for most steepish climbs.
    Did a really hilly 100 mile sportive that had loads of long steep climbs and a few 1 in 4's and it blew my legs to bits.
    Went up to a 12/27 on the rear and this was better the following year (and did loads of strength work on my legs too which also helped)
    It felt like I had an extra easier gear and didn't affect the top speed as the small cog was the same size as before.

    So it does depend on how strong your legs are in the first place really.
  • jboyjboy Posts: 40
    Thanks for advice,

    Realistically I'm not that strong and have not been cycling for more or less a year now. My new bike will be for racing and the odd dry day training. All the events I'll be doing will be flat so I think a setup of 53/39 and 11-25 would be best suited.

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