Mason line rear-wheel alignment

Bruce Miller 2007

Aligning the rear sprocket and drive sprocket minimizes sprocket, chain, and rear tire wear.

The method of alignment discussed here relies upon the technique used by professional carpenters and masons: shim a line away from the work and then make measurements between line and work to obtain equal distances.

Advantages

  • Very accurate
  • Low-cost
  • Compensates for different front and rear tire widths

Disadvantages

  • A bit messy
    (line gets greasy and so do you)

Materials

  • Mason line (approximately 16 feet)
  • Hook
  • Four shims of equal thickness
    (1/4" or 5/16" work well)
  • Ruler
  • Appropriate wrenches

Method


  1. Bike on center stand

  2. Beginning at either front or rear tire, fix string (line) to a spoke.

    Run the line around the outsides of both tires, threading it beneath the frame and through the center stand on both sides before tying it off.

    You now have a taught loop of line all the way around the outside of both tires.
  1. Shim the line an equal distance off both (front) sidewalls of the front tire and both (rear) sidewalls of the rear tire (shown).
  1. Adjust front wheel from side-to-side until the distance between the rear sidewalls of the front tire and the line is equal on both sides.

     



  2. Adjust rear wheel until the distance between the front sidewalls of the rear tire and the line is equal on both sides.

    When distance is equal on both sides the rear tire is aligned.

  1. Tighten axle nuts and re-check the stand-off on both sides of both tires.



  2. If both front distances are still equal and both rear distances are still equal, remove line and ride.