Advertise on Bikeforums.net



User Tag List

Results 1 to 7 of 7
  1. #1
    Tandem Vincitur Ritterview's Avatar
    Join Date
    Sep 2005
    Location
    Northern California
    My Bikes
    BMC Pro Machine SLC01, Specialized Globe, Burley Rock 'N Roll tandem, Calfee Dragonfly tandem.
    Posts
    3,199
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Gear-Calculator.com

    I've been exploring gearing options, and came across this nifty gear selection tool, at Gear-Calculator.com.

    Here I compare the 53-39 double with SRAM 11-36 10-speed cassette, as seen and discussed on this Paketa, with my setup, which is a 53-42-30 triple with Campy 12-29 11-speed.





    This nicely visualizes and quantifies what you get with each setup. The 2X 11-36 has quite similar range, but not nearly the close spacing of the 3X 12-29.

    I really appreciate this close spacing on the riding we do, for example, keeping up with fast single riders on rolling terrain on our club training ride. Making many small shifts while keeping optimum cadence allows us to mix in with the half-bikes, which in comparison to tandems have more variation in speed and rapid accelerations.

    [The graphic was posted by doing a screen shot by pressing CTRL-PRINT SCREEN while on the site, and then PASTE in MS Paint, a Windows accessory program. The image is saved, and then uploaded to Flickr, or easier yet, Tiny Pic, which will provide the IMG code to past right into the post.]

  2. #2
    Senior Member rdtompki's Avatar
    Join Date
    Nov 2008
    Location
    Hollister, CA
    My Bikes
    Volagi, daVinci Joint Venture
    Posts
    3,934
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It's not a bad graphic, but doesn't seem to support arbitrary gearing. Most important - doesn't support the most important feature, a quad chainring
    Rick T
    --------
    Volagi - Triple"ized" and Tubeless
    daVinci Joint Venture

  3. #3
    Tandem Mountain Climber
    Join Date
    Mar 2007
    Location
    San Mateo, CA
    My Bikes
    Calfee Tandem, Custom CAAD9 BB30, 90 Santana Arriva Tandem, 02 CAAD4 errand bike, 87 Cannondale "Black Lightning"
    Posts
    4,090
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I always used the Sheldon Brown calculator, but I like the graphical display this one has. Good find.

    Here's mine: 56/42/30 with Sram XX 10s 11-32



    30x32 is nice (I will most likely even switch back to the 28t chainring after RAAM). I am trying to get away from this habit of mashing I have gotten into the last year or so, and get back to higher cadence. Climbing at 90 rpm is 6.6 mph with the 30x32 or 6.2 mph with the 28x32.

    Since I have been getting back to higher RPM climbing, my power is going up on longer efforts (10+ min).
    http://app.strava.com/rides/666673#9929937 (my cadence here is mostly around 90 rpm, lower when standing)
    *of course this example is my solo bike, and there are differences in preferable cadence between solo and tandem.
    Last edited by uspspro; 06-04-11 at 12:31 PM.

  4. #4
    just another gosling Carbonfiberboy's Avatar
    Join Date
    Feb 2007
    Location
    Everett, WA
    My Bikes
    CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
    Posts
    8,064
    Mentioned
    3 Post(s)
    Tagged
    1 Thread(s)
    I just use a spreadsheet with formulas that calculate the gear-inches. Easy to do, and easy to show several different gearing scenarios one above the other. Also easy to add formulas calculating speed at various cadences in the various gear combinations.

  5. #5
    Tandem Vincitur Ritterview's Avatar
    Join Date
    Sep 2005
    Location
    Northern California
    My Bikes
    BMC Pro Machine SLC01, Specialized Globe, Burley Rock 'N Roll tandem, Calfee Dragonfly tandem.
    Posts
    3,199
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by uspspro View Post
    Here's mine: 56/42/30 with Sram XX 10s 11-32

    ...30x32 is nice I am trying to... get back to higher cadence. Climbing at 90 rpm is 6.6 mph with the 30x32
    Here is a comparison then, at a leg-sparing 90 rpm cadence, between your Team JDRF-IGA and my clubride setups.

    56/42/30 10s 11-32
    52/42/30 11s 12-29



    I hadn't seen that custom ring sizes were available, simply by moving the chainring/sprockets symbols. Neat.

    It shows that we would need much lower gears to maintain a higher cadence. On 7.2% Tollhouse, our cadence was more in the 50-70 range, with a speed of only 3.6 mph.

    As for the top end, if we get any over 30 mph my stoker wigs out, so no point in anything taller.

    To get something like your RAAM setup, I would need to switch to a 28 tooth inner chainring, a 53 tooth outer chainring, and an 11-30 cassette. And then I'd have to make sure that the one-size RD cage could handle the additional chain wrap. That provided, they look similar now, though the 11th cog shows up three times to make the spacing tighter.


  6. #6
    Tandem Mountain Climber
    Join Date
    Mar 2007
    Location
    San Mateo, CA
    My Bikes
    Calfee Tandem, Custom CAAD9 BB30, 90 Santana Arriva Tandem, 02 CAAD4 errand bike, 87 Cannondale "Black Lightning"
    Posts
    4,090
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Ritterview View Post
    It shows that we would need much lower gears to maintain a higher cadence. On 7.2% Tollhouse, our cadence was more in the 50-70 range, with a speed of only 3.6 mph.
    I find climbing at 80-100 rpm makes more power (while seated), I like around 70's for standing. There are so many really steep hills around here that put us into that 50's rpm range, even with your typical tandem gearing, and it's just not efficient.

    So I have no issues with running a 30x32 or 28x32.

    My 32t cog is skipping on my XX cassette (I think it's the inbound limit screw or the aluminum big cog is just worn out), so I have been forced to use the 28t cog as my lowest gear (with 30t chainring, at the moment).. would have helped to have something lower on something like Metcalf (http://app.strava.com/rides/651634#9703410) after climbing Henry Coe at a solid pace earlier that day (http://app.strava.com/rides/651634#9703424).

  7. #7
    Low car diet JiveTurkey's Avatar
    Join Date
    Aug 2007
    Location
    Corvallis, OR, USA
    My Bikes
    2006 Windsor Dover w/105, 2007 GT Avalanche w/XT, 1995 Trek 820 setup for touring, 201? Yeah single-speed folder, 199? Huffy tandem.
    Posts
    2,372
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by uspspro View Post
    My 32t cog is skipping on my XX cassette (I think it's the inbound limit screw
    Easy way to find out.
    Quote Originally Posted by slopvehicle View Post
    Not wearing a helmet makes me more aware of my surroundings. I find myself anticipating the hardness of concrete 50 or 100 feet in front of me, it's almost a zen-like connection between my face and the pavement.

Posting Permissions

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