Crank advice-length

passout
passout Posts: 4,425
edited January 2013 in Road buying advice
Getting a new chainset. I'm 5'9'' with a 31'' inside leg. I don't race but do challenging rides - long, hilly and reasonably paced. Cadence is bit lower than is should be.

172.5mm do you think?

Cheers
'Happiness serves hardly any other purpose than to make unhappiness possible' Marcel Proust.

Comments

  • chrisvanderkaap
    chrisvanderkaap Posts: 323
    yes, considering your height and riding style 172.5 should be ideal. I'm not a firm believer in the explanation of more leverage by increasing crank size.While I have positively experienced the ability to move a big gear in sprint with a (relatively) shorter crank. I wonder what other peoples opinion is on that one.

    maybe of topic? I often get this question in the shop in relation to running oval rings (q-rings etc). While I know that they can help riders (especially with higher cadence), I wonder how the extra leverage gained by capitalizing on the downstroke (and pacing through the upstroke) is related to their chosen crank length.
  • simonj
    simonj Posts: 346
    I'm 5'10" with 31" inside and mine works out to be 170mm. I worked it out using a calc based on hip joint to floor, but I've just found a calc based on inside leg in cm * 2.16 and it works out to the same figure also.
  • bernithebiker
    bernithebiker Posts: 4,148
    passout wrote:
    Getting a new chainset. I'm 5'9'' with a 31'' inside leg. I don't race but do challenging rides - long, hilly and reasonably paced. Cadence is bit lower than is should be.

    172.5mm do you think?

    Cheers

    This question comes up a lot, and opinions differ, but my take on it is that if you want to increase your cadence, (which I would say is a good thing), then go a bit shorter on the crank. I'm a touch smaller than you and I use a 170.
  • passout
    passout Posts: 4,425
    Good advice, thanks.
    'Happiness serves hardly any other purpose than to make unhappiness possible' Marcel Proust.
  • danlikesbikes
    danlikesbikes Posts: 3,898
    I'm 5"9 and ride 172.5, but as others have said they come out at 170. To be honest though I doubt that you would notice a 2.5m difference.
    Pain hurts much less if its topped off with beating your mates to top of a climb.
  • Omar Little
    Omar Little Posts: 2,010
    I have bikes with various crank lengths - 165mm, 172.5mm and 175mm. Obviously each bike feels different but i cannot tell the difference in the crank length!
  • ukg3pxc
    ukg3pxc Posts: 37
    Can you get anything longer than 175? I'm 6 ft 5
  • simonj
    simonj Posts: 346
    SRAM Black say :-

    Available Arm Lengths

    165mm, 167.5mm, 170mm, 172.5mm, 175mm, 177.5mm

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