Advertise on Bikeforums.net



User Tag List

Results 1 to 11 of 11

Thread: GI calculators

  1. #1
    Senior Member
    Join Date
    Aug 2009
    Location
    central Ohio
    My Bikes
    Schwinn Madison, Windsor Dover
    Posts
    940
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    GI calculators

    Looking at the Sheldon Brown gear calculator and the one found on the Wabi site show two significantly different calculations. i.e., the Wabi calc (for 700c) for a 48/18 reads to be a 69gi, but when using the Sheldon calc, and after selecting the correct tire size and crank length reads to be a 67.4gi. Which is more accurate? Which calculator do you all use? Thanks.

  2. #2
    Senior Member Santaria's Avatar
    Join Date
    Apr 2005
    Location
    Brownsville, TX
    My Bikes
    Surly CC
    Posts
    2,175
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

  3. #3
    7-speed doomsday prepper ThermionicScott's Avatar
    Join Date
    Aug 2011
    Location
    CID
    My Bikes
    1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX
    Posts
    9,724
    Mentioned
    17 Post(s)
    Tagged
    0 Thread(s)
    I use www.gear-calculator.com. You can calculate a bunch at once, and it's interactive.
    Quote Originally Posted by chandltp View Post
    There's no such thing as too far.. just lack of time
    RUSA #7498

    ISO: 49T 130BCD 3/32" road chainring, preferably silver and classic-styled.

  4. #4
    Fresh Garbage hairnet's Avatar
    Join Date
    Apr 2009
    Location
    Los Angeles
    Posts
    11,424
    Mentioned
    20 Post(s)
    Tagged
    0 Thread(s)
    This one has passed around here a lot
    http://software.bareknucklebrigade.com/

    It even calculates your sw8 skid patches
    Quote Originally Posted by Scrodzilla View Post
    I often need to flip my brain to the freewheel side when reading this forum.
    Bikerowave
    My Bikes

  5. #5
    Morton Nagrom_'s Avatar
    Join Date
    Dec 2011
    Location
    East Bay
    My Bikes
    CAAD3, CAAD10, GT Avalanche, GT RTS-3
    Posts
    9,862
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    I use an iOS app.
    Quote Originally Posted by seau grateau View Post
    No offense but you're an idiot.
    PedalRoom

  6. #6
    Senior Member swisscheese's Avatar
    Join Date
    Nov 2011
    Location
    Alberta
    My Bikes
    http://www.pedalroom.com/member/swisscheese
    Posts
    77
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Haven't actually looked into if it;s accurate or not, but this one's simple and quick to use.
    http://deafpigeon.co.uk/gear-calculator.php

  7. #7
    Senior Member
    Join Date
    Aug 2009
    Location
    central Ohio
    My Bikes
    Schwinn Madison, Windsor Dover
    Posts
    940
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks for all the links, everyone!

    Interesting - the All City calc matches that of Sheldon's, and the Deaf Pigeon matches that of Wabi's. The ones that have the tire size selection match up and the ones that don't match up...
    Last edited by bfloyd6969; 04-15-12 at 10:23 PM.

  8. #8
    %#&*#%>?% Build your own's Avatar
    Join Date
    Feb 2008
    Location
    Mass
    My Bikes
    Pake,Shogun,Nishiki,Motobecane
    Posts
    845
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The ones without specific size probably round up to 27 for a 700c(it's more ~26.7),hence the bigger number. I usually just calculate myself,easy enough. Chainring/cog x Tirediameter

  9. #9
    Senior Member
    Join Date
    Aug 2009
    Location
    central Ohio
    My Bikes
    Schwinn Madison, Windsor Dover
    Posts
    940
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Build your own View Post
    The ones without specific size probably round up to 27 for a 700c(it's more ~26.7),hence the bigger number. I usually just calculate myself,easy enough. Chainring/cog x Tirediameter
    Thanks. How does the tire width and crank arm length fit into this - as used on the Sheldon gear calculator?

  10. #10
    %#&*#%>?% Build your own's Avatar
    Join Date
    Feb 2008
    Location
    Mass
    My Bikes
    Pake,Shogun,Nishiki,Motobecane
    Posts
    845
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Increased width also increases height,increasing overall diameter. The Crankarm length on Sheldons calculator is needed to calculate gain. It doesn't effect GI.

  11. #11
    Senior Member
    Join Date
    Aug 2009
    Location
    central Ohio
    My Bikes
    Schwinn Madison, Windsor Dover
    Posts
    940
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    ^^ Thanks.

Posting Permissions

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