170mm or 175mm crankset?

cheese_toastie
cheese_toastie Posts: 35
edited May 2011 in MTB workshop & tech
Hi, the Shimano 175mm Acera 42 32 22 crankset arm got damaged recently on my bike and I would like to replace it with another as it is original on the bike. A new crankset is only £36 but I can only get it in 170mm arm length.
I could get a Shimano Alivio 42 32 22 in 175mm for about the same price but this has no chain guard and I would need to change to a different bottom bracket axle length.
Does anybody know if there is much difference when riding, 5mm doesn't seem a lot?
Thanks in advance for any advice.

Comments

  • omegas
    omegas Posts: 970
    A shorter crank arm is more suitable to a small frame or low bottom bracket to give you more ground clearance for your pedals.
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  • miss notax
    miss notax Posts: 2,572
    Yep, how tall are you? I use 170 cranks as i'm only 5ft 4 and I find them better for me :D
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  • carrera_vulcan
    carrera_vulcan Posts: 125
    http://cgi.ebay.co.uk/SUNTOUR-XCT-MTB-B ... _730wt_905

    Take a look at these. They are 175mm and look pretty good. I have the white ones and I bought them from the same shop from ebay. They are pretty good.
  • buckmulligan
    buckmulligan Posts: 1,031
    Seriously, 5mm?! It might be a lot when looking at BB spindle lengths, but crank arm lengths?! Surely it's completely insignificant?
  • warpcow
    warpcow Posts: 1,448
    5mm difference will barely be noticable, other than in improved ground clearance. I've got 170 on 1 bike and 175 on 2 others, I'm 5'11". At worst you'll have to raise your saddle by a whole 5mm!
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  • Anonymous
    Anonymous Posts: 79,667
    EDIT: Ignore that I'd got the original post totally arse above tit :oops: :lol:
  • stubs
    stubs Posts: 5,001
    I fitted an SLX twin and bash to a mates bike, it had 175mm arms. Months later I got around to cleaning the muck off his old XT hollowtech I crankset prior to fitting new rings and realised it had 170mm stamped on the arms. My mate never even noticed the 5mm difference and he would still be none the wiser if I had just binned the old set.
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  • nicklouse
    nicklouse Posts: 50,675
    I run 165/170/175 I can tell a bit of difference. I dont like 170 on an XC bike. but it is fine on the DH bike. 165 on the street bike is OK but.... it feels a bit odd.
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  • cheese_toastie
    cheese_toastie Posts: 35
    Hi, thanks for the replies. I am 6ft and the frame is a 21in so raising the saddle 5mm will be no problem. The way I ride I don't think the 5mm will make too much difference. I like the look of those Suntour XCT but I do prefer the ones with a chain guard so have just ordered a set of 170mm Acera ones off ebay.
    Thanks again for the advice.
    I

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