Results 1 to 10 of 10
  1. #1
    mtbr member
    Reputation: JeffSpicoli's Avatar
    Join Date
    Jan 2008
    Posts
    137

    Crankset 180mm vs. 175mm. vs.170mm

    Thinking of upgrading crankset; but not sure pros and cons of each....Currently ride on 175mm...Any advice would be helpful..

  2. #2
    *****************
    Reputation: Bikinfoolferlife's Avatar
    Join Date
    Feb 2004
    Posts
    12,379
    Depends on your measurements and preferences, so hard to say. In general a shorter crank will enhance spinning, a longer crank will enhance torque. Who knows maybe a 185 or 165 or maybe a 172.5 or 177.5 might be better for you?
    "...the people get the government they deserve..."
    suum quique

  3. #3
    mtbr member
    Reputation:
    Join Date
    Nov 2006
    Posts
    792
    Size and inseam would help. I'm 5'7" with a 32" cycling inseam (30" pant leg). I ride a 172.5 xtr 970 crank and it's perfect. I've also ridden 175mm without trouble but the shorter crank feels better.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    303
    Unless you are on the extreme of one side or the other of height/leg length, I would not sweat it and just get a 175mm crank. It is probably what you have now. There is probably a fit formula out there that can help you determine the ideal crank length. 2.5mm is less than the thickness of two dimes stacked on each other. 5mm is less than four dimes stacked up. It is only a 2.8% change in length going from a 175 to a 180mm crank and a 1.4% change going from a 175 to a 177.5. Also if you tweak a crank arm, I would guess odds are in your favor of finding a 175 replacement. The flip side is if you want to try a different length out, go for it. It is probably not gong to be a drastic change from what you have now.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Aug 2006
    Posts
    251
    Quote Originally Posted by chiplikestoridehisbike
    Unless you are on the extreme of one side or the other of height/leg length, I would not sweat it and just get a 175mm crank. It is probably what you have now. There is probably a fit formula out there that can help you determine the ideal crank length. 2.5mm is less than the thickness of two dimes stacked on each other. 5mm is less than four dimes stacked up. It is only a 2.8% change in length going from a 175 to a 180mm crank and a 1.4% change going from a 175 to a 177.5. Also if you tweak a crank arm, I would guess odds are in your favor of finding a 175 replacement. The flip side is if you want to try a different length out, go for it. It is probably not gong to be a drastic change from what you have now.
    Nicely put into perspective!

    Nick

  6. #6
    mtbr member
    Reputation: JeffSpicoli's Avatar
    Join Date
    Jan 2008
    Posts
    137
    Thanx 4 the advice!

  7. #7
    mtbr member
    Reputation:
    Join Date
    Jun 2008
    Posts
    300
    The range of crank sizes always makes me laugh - 170 / 175 / 180 - that's a whole 10mm or 1 cm. Enough to move mountains? Probably not.

  8. #8
    NMBP
    Reputation: crashtestdummy's Avatar
    Join Date
    Jun 2005
    Posts
    2,100
    Quote Originally Posted by ForestHorse
    The range of crank sizes always makes me laugh - 170 / 175 / 180 - that's a whole 10mm or 1 cm. Enough to move mountains? Probably not.
    Have you ever actually tried different crank lengths? 5mm may seem insignificant, but I can certainly tell the difference.
    Riding Fat and still just as fast as I never was.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Jan 2005
    Posts
    1,587
    180mm, you might have to be real careful leaning the bike and pedaling simultaneously, the inside foot anyway
    "He can make even a global summit meeting seem like a kegger." M. Dowd, NY Times, 19 July 2006

  10. #10
    Frt Range, CO
    Reputation: pursuiter's Avatar
    Join Date
    May 2008
    Posts
    2,445
    Quote Originally Posted by ForestHorse
    The range of crank sizes always makes me laugh - 170 / 175 / 180 - that's a whole 10mm or 1 cm. Enough to move mountains? Probably not.
    Yes, but the circle that your feet follow is twice that diameter. 10mm difference in crank lenght is almost an extra inch diameter and almost 3 inches perimeter distance. When I road USCF I could tell the difference between 170 and 172.5.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •