correct crank length?

Discussion in 'Cycling Equipment' started by veloci, Oct 15, 2006.

  1. veloci

    veloci New Member

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    I am about 5'11" and use 175mm cranks. i am ready to switch my FSA Mega Exo compact for a brand new Record carbon crank. the questions are the following:

    will these cranks fit my wife? she is 5'1" (inow, she is pettite) she is riding 170mm now. will the 175 mm hurt her riding at all?

    let me know,
     
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  2. 1id10t

    1id10t New Member

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    Hi veloci,

    Here's a link to Sheldon Browns site regarding crank length.

    http://www.sheldonbrown.com/cranks.html

    And another site

    http://www.nettally.com/palmk/crread.html

    I imagine there will be all sorts of opinions out there regarding what is right or wrong. Long cranks give good leverage while shorter cranks allow you to spin. I'm 5'5 with an inseam length of about 75cm and I use three different crank lengths. My road bike has 172.5mm, my MTB has 175mm and my commuter has 170mm. Haven't had any real issues and haven't noticed the difference.
     
  3. 531Aussie

    531Aussie Well-Known Member

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    that is MASSIVE for her. Even 170 is too big.

    She should be on no more that 165mm, and I only say that becasue 165 is most readily available short length. She probably should be on shorter.

    I'm 6ft with long legs, (89.5cm inseam), and I've ridden everything from 165 (track bike) to 180 (big mistake), and I'm now on 172.5.
     
  4. 531Aussie

    531Aussie Well-Known Member

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    I'm not having a crack at ya, and i guess you just posted these links as contrasting views, but I wish people would stop posting that Kirby Palm bollocks. :) The bottom line is that no pro IN THE WHOLE WORLD over about 5ft8" rides cranks that are 21.6% of their inseam, and the shorter guys only ride relatively long cranks because they're used to them, because that's what came on the first bikes they bought. Even the 'big crank' riders (Boonen, 6'3", rides 177.5, and Indurain, 6'2", rode 180s and 190s for time-trials) used cranks well under Palm's recommended length.

    It's funny; there are millions of websites covering gazillions of topics which are readily dismissed as kooky, but if someone puts up a bogus theory on crank length, it's accepted as referable science :)
     
  5. gclark8

    gclark8 New Member

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    All good advice above.

    I work on seat height to crank length.

    My GF rides 615mm seat height and 152 or 160mm cranks depnding on what's available, that means the pedal circle is about half the BB to seat distance, She is 5' tall on a good day.

    I another friend rides 650mm seat height with 165mm cranks.

    I ride 700mm seat and 170mm cranks.

    You should be 175 or 172.5mm depending on leg length.
     
  6. bobbyOCR

    bobbyOCR New Member

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    I think it is highly subjective.

    Road: 172.5

    MTB singlespeed: 175

    Road Singlespeed: track 170mm

    Moving from 170 to 175 is a huge difference. It feels the most comfortable spinning 172.5 or 170. the 175 is more for the uphills.
     
  7. 531Aussie

    531Aussie Well-Known Member

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    it is, but aren't you a short guy?

    175 is pretty big for someone on a 54
     
  8. bobbyOCR

    bobbyOCR New Member

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    It would be incredibly uncomfortable on my road bike, but my singlespeed needs cranks with leverage to climb the hills/have a more even distribution of power for traction. Also I'm pretty sure I have comparatively long legs.
     
  9. 1id10t

    1id10t New Member

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    That's cool. I agree that to ride with cranks that are way too big would not be beneficial. I ride the ones I have because i'm used to them and don't notice any real difference. I'm not competitive or very serious a rider so probably don't have as much of a reason to be spot on with bike's setup. Having said that though, I do try to get it within reason so i'm comfortable and so I get a reasonable return for my effort. I certainly wouldn't go above 175mm.
     
  10. wakked1

    wakked1 New Member

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    My GF is 5'4" (fairly average in proportion) and she just went from 170 to 165 mm cranks. Made a huge improvement.. esp in out of the seat climbing. Before she was pogo-ing around everywhere. 175 is waaay way too long for someone 5'1".
     
  11. veloci

    veloci New Member

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    thank you guys. i guess i will be placing my cranks for sale in E-bay tonight.

    thank to everyone that replied.
     
  12. 531Aussie

    531Aussie Well-Known Member

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    cool...I'll be using that in future. :) Thanks
     
  13. wakked1

    wakked1 New Member

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    My lawyers will send you a copy of my standard royalties form shortly. :D

    In Melbourne eh? Say hi to my dad!
     
  14. 531Aussie

    531Aussie Well-Known Member

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    no worries

    If he lives on Beach Rd., just tell him to stand outside his house and I'll wave as I go by. :p

    [​IMG]
     
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