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Technical FAQ: Duplicating bike position feedback

  • By Lennard Zinn
  • Published May. 17, 2007
  • Updated Nov. 17, 2009 at 3:18 PM EST

Feedback on a recent column on duplicating position on multiple bikes.

Dear Lennard,
If someone is trying to duplicate their position from one bike to another, the first thing to do is to make sure the crank length is the same on both  bikes. If the cranks are different, you’ll never effectively duplicate your riding position. I’d also add the bar bend (drop and reach) to the list of things to measure and duplicate.
-Paul

Dear Lennard,
With the plum line for saddle set back, you have to make sure the bike is level, and the only effective way I’ve found to do that, given sloping top-tubes etc., is to run a line between the dropouts (clamping the line in the QR’s is a good cheat) and hanging a line level, then shifting the bike around on the workstand until it is level. I also measure the distance from the saddle nose to the virtual point on the brake levers, as different bars (as if you actually would even think of using different bars on different bikes!) have different reaches, and reach to the levers affects how the bike handles out of the saddle.

I’ve also found that masking tape is very handy for marking locations on the bike for setup (especially the center of the saddle for saddle height). Good also, as I’m sure you do, to think of your position as three points in space that you fill the bike and components into – I think, conceptually, this makes multiple bike fitting easier . Park Tool has a great little chart that you can download from their Web site that you can use to record your position.
-Bob

Dear Bob,
Great points, but it only matters if the bikes are not level if they are not held exactly the same when measured. I have a drawer into which I’ve drilled a hole to accept a long, straight bike hook. Sliding the drawer in and out so that the bike stands up perfectly straight, I bungee the head tube of each bike up against that hook when I take the measurements, so the relative plumb-line measurements can be compared, even if my floor is not perfectly level.
-Lennard

FILED UNDER: Bikes and Tech / Technical FAQ TAGS: / / / / / /

Lennard Zinn

Lennard Zinn

Our longtime technical writer joined VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and the Art of Mountain Bike Maintenance and Zinn and the Art of Road Bike Maintenance, as well as Zinn and the Art of Triathlon Bikes and Zinn's Cycling Primer: Maintenance Tips and Skill Building for Cyclists. He holds a Bachelor’s degree in physics from Colorado College. Readers can send brief technical questions to Ask LZ.

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