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Rear travel measurement method?

Discussion in 'Downhill & Freeride' started by WheelieMan, Oct 18, 2005.

  1. WheelieMan

    WheelieMan Monkey

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    I have been designing (not building unfortunately) my own bikes for a while now and have been stumped by something recentley. I have always thought that the rear travel measurement is the total displacement of the axle. In other words, the straight line distance from the rest position to the bottom out position. However, I have also heard that rear travel is measured by the total "vertical" distance that the axle travels. This might seem kinda trivial, but with high-pivot bikes, I have found up to a 7mm difference between the two measurements. Is one method more correct than the other in the mountain biking industry?
     

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  2. WheelieMan

    WheelieMan Monkey

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    DW? Kyle@PDC? Sully? Noel? Anyone? Bueller?
     
  3. vitox

    vitox Turbo Monkey

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    general concensus seems to be distance from topout to bottomout, at the rear wheel axle.
     
  4. ohio

    ohio The Fresno Kid

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    Different companies measure it differently. Rarely is an 8.5" travel bike actually exactly 8.5". For shock tuning the instantaneous leverage is what's most important, and if you back out of that for a single pivot, you get the length of the path itself rather than the chord length. For linkage bikes, it's a moot point, because that number doesn't really effect anything else. For designing purposes, that is.

    For comparing bike to bike, straight line distance between axle at top-out and bottom out should be the standard measurement, IMO.
     
  5. BMXman

    BMXman I wish I was Canadian

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    I don't think the distance of an axle path that runs parallel to the ground should be counted...I mean frames that have an S, J, or L curve...but that's just me...D
     
  6. verticult

    verticult Chimp

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    I use "vertical wheel travel" . distance from lowest position to highest position measured in a vertical line. Sinister Bikes