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  1. #1
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    Crank Length Question

    I was recently reading a bunch of websites and came across this



    Is this true b/c if it is I have been way over my crank length for years. All my bikes have come with 180mm (7 inches from eye to eye center) and I only have a 28 1/2 inch inseam. Should I shorten the cranks to 170mm? Or would it really make that much of a difference? Does a shorter crank throw off handling Characteristics? I have never ridden anything other than 180mm and checking my last 3 bikes they are all the same. It could explain why I suck on climbs so much but I doubt it


    BTW: I found this:
    Mountain bikes generally get cranks 2.5–5mm longer than road bikes; that is, you might want a 175mm crank on your mountain bike if you’re set up with a 172.5 on your road bike.

    and I believe that the chart was for road cranks but it doesn't say so on the site.
    Last edited by Muggsly; 01-24-2006 at 02:02 PM. Reason: Added info to be more clear.
    Progression is fine just remember to respect your roots.



    [SIZE="3"] Click to see my Orange Ano Blur LT[/SIZE]

  2. #2
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    Dude!
    I am 5'4" with a 29" inseam.
    I used to have 180m cranks on my MTB and 175m cranks on my roadbike.
    I started to log on miles and my knees developed tendonitus!
    I had to go put shorter 175m cranks on my MTB. I bought a small 04' team Scalpel that came with 172.5m cranks with a wide as Q-factor for large frame people (chainrings stuck way out even farther than XT!)
    I had to get rid of it!
    I am on 175m XTR 960 cranks that I narrowed the Q-factor and it feels great for a small dude like me instead of riding a horse like they first came!
    My roadbike, I went down to a 170m compact FSA but I lost alot of leverage!
    I am on 172.5 length crank arms and now I can scare the bigger roadies when it's time to sprint!
    To me, crank length did make a difference to me!
    I am not a spinner anyways so the recommended short cranks for my size just did'nt work for me.
    Cheers!

  3. #3
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    Quote Originally Posted by Fast1000
    now I can scare the bigger roadies when it's time to sprint!
    he can too!

    sup SuperV?

  4. #4
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    Does size really matter?

    Quote Originally Posted by jjay
    he can too!

    sup SuperV?
    Fine jjay!
    Trying to help a brotha out!
    Have you read your private messages??
    I will answer that for you! "NO!"

  5. #5
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    Reputation: Bikinfoolferlife's Avatar
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    I'd say that chart is for road bikes primarily from what I've seen before. 7 inches exactly would more likely be a 177.5 mm crank, still kinda long for what would normally come on a bike for your size IME. Personally I use 172.5 road/175 mtn; when I tried a 177.5 on my ss my knees said go back to 175. The only effect a longer crank might have on handling that I can think of is that it's closer to the ground and easier to strike on obstacles or in turns. You might find spinning a bit easier with a shorter crank. I wouldn't jump from 180/177.5s to 170s; I'd try 175s or 172.5s first based on how my knees reacted to a small increase, but maybe it's less likely to cause pain by going shorter?
    "...the people get the government they deserve..."
    suum quique

  6. #6
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    They are 7.1 approx so they must be a 180mm since i have never seen a 177mm unless Spec and Giant both make odd sizes. My giant is a Small and My spec is a medium you figure that at least the giant would come with smaller crank arms but I guess not. I am guessing that I will have to add new Cranks to my Wishlist. I was looking at Crank arms for my Spec and they are nearly as expensive as a whole new crank set. Also having an Octolink BB unfortunately sticks me in the shimano realm. Well I guess an new BB wouldn't hurt me either.


    And I was thinking that I would go to a 175mm at 1st and see if I like it. My LBS is a road heavy shop so I might just jump on a couple roadies with different size Crank Arms to see what I like best.

    Thanks for all the info guys it is much appreciated.
    Progression is fine just remember to respect your roots.



    [SIZE="3"] Click to see my Orange Ano Blur LT[/SIZE]

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