Over time, a wheel may become out of true. This means that the
midplane of the wheel is no longer a plane whose normal is parallel
with the axis of rotation. In this case, it becomes necessary to
adjust so that the wheel becomes a plane once again.
Tools/Parts Required
Dial indicator (optional)
Spoke wrench
Procedure
Mount the dial indicator to a stationary part of your bike (ie frame).
Mount it so that it detects deflections which are parallel to the axis
of rotation of the wheel (see Figure 1)
Figure 1: Direction to mount dial indicator
Spin the wheel around several times while watching the dial indicator.
Make a note of what the average value is (ie where the needles ocsillates around).
With this average value in mind, turn the wheel until you come to a point
which is deflected the most from the average (ie most out of true).
Use the spoke wrench to turn tighten or loosen the spokes. This will pull the
rim to one side or another depending on which way the spoke is aligned. Tightening
the spoke will pull the rim in the direction that it is aligned. Also keep in mind
that the nipples are "backwards". That is, if you are looking at the inside of the
rim, turning the nipple counter-clockwise will tighten the spoke. Be sure to only
tighten in small increments (ie 1/2 turns). Also be sure to tighten the other spokes
near the one that you just turned. See Figure 2 for more information.
Figure 2: Relationship between spoke rotation and wheel translation
Repeat this process until the rim is true (ie the dial indicator does not move much
when the wheel is spun in a complete revolution.
