Advertise on Bikeforums.net



User Tag List

Results 1 to 10 of 10
  1. #1
    Senior Member
    Join Date
    Mar 2005
    Posts
    239
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    longer crank arms what will i notice diferrently

    i have had 170 cranks thats what came on my bike. if i put on some 172.5 what will i need to do? maybe lower the saddle a bit? or is it not that huge of a jump.

  2. #2
    Senior Member Retro Grouch's Avatar
    Join Date
    Feb 2004
    Location
    St Peters, Missouri
    My Bikes
    Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
    Posts
    23,898
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It's 1/8 of an inch. That's not very much. You might not even notice.

  3. #3
    Member
    Join Date
    Jul 2006
    Location
    Berkeley/Santa Cruz
    My Bikes
    HPL steel track, Marin Muirwoods, 1985 Aluminum Trek 2000(?)
    Posts
    47
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You probably will not need to move the saddle, but the longer cranks will feel different. Maybe better, ask your knees after riding on it for a while.
    2003 Marin Muirwoods/Human Propulsion Laboratory custom track/2007 Trek 5000 (Ultegra and FSA)
    sR+++!% bR2HF rERTCP! raR5 ld+km so++ aC vP21/C16 c++ m++% bb+ rSH rRI rPR rFG rDE rTR rGL rWW rIHC i++

  4. #4
    ride, paint, ride simplify's Avatar
    Join Date
    May 2005
    Location
    San Diego
    My Bikes
    Cannondale R300 Caad2
    Posts
    1,202
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Read this whole thread (especially pages 3 and 4) for a truly exhaustive analysis of all the implications of different crank lengths.

    Here's a list of pro crank lengths for you tekkies!

  5. #5
    Senior Member
    Join Date
    Aug 2005
    Location
    Pittsburgh, PA
    My Bikes
    '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
    Posts
    25,769
    Mentioned
    7 Post(s)
    Tagged
    0 Thread(s)
    My guess is you will notice the difference for, maybe, 10 minutes. After that they will feel just like your 170's. I have an MTB refitted for the road that has 175 mm cranks and all of my road bikes have 170's. I barely notice the transition even when riding them back-to-back.

  6. #6
    sch
    sch is offline
    Senior Member
    Join Date
    May 2003
    Location
    Birmingham. AL
    Posts
    2,599
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    I am height challenged at 66" and experimented in the '70s with 175mm TA cranks and
    it was noticeable and annoying compared to 170mm, mainly the slightly larger crank
    circle threw me off. The torque variances are small, but larger pedaling circle lead me
    rapidly back to 170mm. Altho my ATB is 175, pedaling over wildly varying terrain rather
    than smooth asphalt swamps out the difference there, never noticed. A significant
    variance is your height, if you are 68-72" especially, you will likely never notice the
    change.

  7. #7
    In beaurocratic limbo urbanknight's Avatar
    Join Date
    Mar 2006
    Location
    Los Angeles, CA
    My Bikes
    Specialized Allez, K2 Razorback
    Posts
    22,457
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I didn't notice the difference between my mtb, roadie, and track bike until someone told me they had different lengths (180, 172.5, and 167.5 respectively). The I felt the difference
    "Well, I guess you can cut the arts as much as you want... Sooner or later, these kids aren't going to have anything to read or write about." (Richard Dreyfus as Glenn Holland)

  8. #8
    Member
    Join Date
    Jul 2006
    Location
    Berkeley/Santa Cruz
    My Bikes
    HPL steel track, Marin Muirwoods, 1985 Aluminum Trek 2000(?)
    Posts
    47
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I had 175s briefly (because they were on hand) and it made my knees hurt. I have bikes with 165s (e.g. the fixie) and 170s, those are both fine.
    2003 Marin Muirwoods/Human Propulsion Laboratory custom track/2007 Trek 5000 (Ultegra and FSA)
    sR+++!% bR2HF rERTCP! raR5 ld+km so++ aC vP21/C16 c++ m++% bb+ rSH rRI rPR rFG rDE rTR rGL rWW rIHC i++

  9. #9
    Senior Member
    Join Date
    Dec 2004
    Location
    Athens, Ohio
    My Bikes
    Custom Custom Custom
    Posts
    5,104
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You will probably have to adjust your seat (if you are picky like me). I upsized from 172.5 to 175 and had to lower my seat a few mills.

    I had 172.5 on my road bike and when I went to build up my TT bike, I bought some used 175's on ebay. I liked them so much I decided to get 175's when I upgraded my group.

    But really the difference is miniscule. The percentage change between crank arm length is so small compared to other measurements. I was told to try to keep all your cranks the same length between bikes so they all feel the same. But obviously it doesnt apply to track bikes since your crank length is pretty much determined by how steep the banking is.

  10. #10
    Super Moderator
    Join Date
    Feb 2007
    Location
    Tariffville, CT
    My Bikes
    Tsunami Bikes
    Posts
    12,499
    Mentioned
    22 Post(s)
    Tagged
    0 Thread(s)
    I have short legs (ride a Small Giant and never taller than a 51 cm frame) and I ride 175's. I used to ride 170's all around - mtb, road, track. Now I have 175's mtb, road, tandem (haven't touched the track bike in a while). I tend to spin till I'm suffering then I push (doesn't everyone?). My strength is sprinting, I can't climb or TT to save my life.

    My thoughts on cranks:
    http://sprinterdellacasa.blogspot.co...m-lengths.html

    Basically I would save significant ergonomic changes for the off season. Significant = crank length, perhaps shoe or pedal swaps if they are radically different. Anything to do with your hips down. bar, stem, seat, etc are not as significant and easy to change back.

    hope this helps
    cdr

Posting Permissions

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