Crank arm lenth

Fred Steele
Fred Steele Posts: 81
edited January 2009 in Workshop
Probably an old chestnut of a topic, so apologies in advance.

Mine are 175mm which came with my Focus Cayo. Even though I'm 6'4" they feel much longer than the 170's I'm used to and it's more difficult to get a good spin up, especially when sprinting away from a standstill. I seem to have to rock the bike with my arms to use the crank length fully. Has anyone else found that a few millimetres' difference from what you're used to can make a big difference?

Comments

  • bill57
    bill57 Posts: 454
    See "Road Beginners" ?????
  • rjsmith
    rjsmith Posts: 1,924
    I've not noticed such a difference when trying bikes. Only really at 177.5mm on the TT bike maybe.
    At 6ft 4in many would suggest you should be on at least 175mm as standard anyway.
  • Fred Steele
    Fred Steele Posts: 81
    Yeah I understand the science, but I just prefer shorter cranks and wondered if this was common. I guess I've answered my own question.

    I don't think I was ever beaten off the lights to at least 100 metres when I had 170's.
  • maddog 2
    maddog 2 Posts: 8,114
    just use what you prefer. I too find 175s a tad long for road work and 172.5s are just perfect. Might be worth a try. 170s for someone 6'4" is on the short side. You might find a longer crank feels a bit different at first but then you adapt.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • octav
    octav Posts: 50
    I'm 5"10 and I used only 170 mm cranks up to now(this year 6000 miles). I switched 2 weeks ago for a 175 to notice the difference. The only difference that I noticed is that the 175 is slower on sprints and puts more tension on my knees(I changed a little bit the saddle position for the 175). I think that the "perfect" compromise is the 172.5. I feel the 170 too short.
    Regarding the cadence I didn't notice any change. My usual fan-style 100+
  • cougie
    cougie Posts: 22,512
    I've used lots of different langth cranks, and I couldnt really say that they made any difference.
  • octav
    octav Posts: 50
    I talked to many pro cyclists from my town and they all said that if I have a mountain stage to compete in I should go for a 175 and if I have a circuit stage(more laps) I should go for the 170 because there are a lot of sprints and changes of tempo. So I believe that if I'm an non-pro I should go for the 172.5 because I don't want to change the crank everytime I go to a different type of event.
  • shockedsoshocked
    shockedsoshocked Posts: 4,021
    Surely you just ride what feels comfortable for you? I'm 6"2 and use 175. A team mate is a similar size to the OP (6"4) and he uses 180s.
    "A cyclist has nothing to lose but his chain"

    PTP Runner Up 2015
  • mercsport
    mercsport Posts: 664
    It goes without saying - I hope - that you dropped the saddle/ seatpost to compensate ?
    "Lick My Decals Off, Baby"
  • octav
    octav Posts: 50
    with the 170 I had the saddle at 75.5cm from the BB and with the 175 i lowered the saddle at the distance of 74.5 from the bb . I want to train the next 1000 miles with the 175 and I hope I will reach a verdict after those miles :D
  • Fred Steele
    Fred Steele Posts: 81
    Just switched to 170's from 175's. It's like coming home! My sprint is back and no more pain! Since I'm 6'4" this proves that it's personal preference thing.

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