Motorcycle Wheel Building

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Motorcycle Wheel Building

John H Glimmerveen Licensed to About.com

Although cast aluminum wheels on motorcycles have been around since the 1920s (see sidecar history—1929 Bohmerland), the wire spoke wheel was the primary source of wheel construction until the 80s, and can still be seen on many different types of motorcycles.

The advantages of the wire spoke wheel are that they are light weight, easy to maintain, and they are relatively inexpensive. However, the steel chromed rims tend to rust (both inside and out) and spokes can break. It is, therefore, common to find that a classic motorcycle requires new rims and spokes at some time. And although this job is somewhat complex it is not beyond the competent home mechanic.

Fitting New Rims and Spokes

Rebuilding a wire-spoked wheel involves replacing both the rim and the spokes—it is pointless just replacing one or the other, rather than both, as this is a labor intensive operation.

Assuming the old rim and spokes have been removed, the replacement process starts with laying the new rim inside the hub and lacing a few spokes to locate the two parts (see photograph ‘A’). The wheel should then be turned over and the opposing spokes should be added to centralize the hub inside the wheel rim. The spokes should then be finger tightened to start the alignment process.

To ensure the rim is located correctly in relation to the hub, the mechanic must check the basic offset at this point as seen in photograph ‘B’ (further checks will be needed as the assembly proceeds).

Wheel Truing

To check the wheel for true, or run-out as it is sometimes called, it must be supported on stands as seen in photograph ‘C’. The wheel spindle is ideal for the process. With the wheel supported on stands, the mechanic should spin it then offer up a dry erase marker slowly toward the rim. Run out (represented by high points) will contact the marker first leaving a line—see photo ‘D’. The mechanic must check both the wobble (run-out) and the vertical movement.

With the assembly close to true, the mechanic can add the remaining spokes (finger tight); however, he must mark the first set of spokes he added as these will now be relatively tight.

With all the spokes placed, the mechanic should begin to tighten all of the remaining spokes. However, it is important to realize that the tightening process must be done in sequence. For example, four spokes tightened at the twelve o-clock position must have the corresponding spokes at six o-clock tightened next. In addition, the mechanic must remember that tightening a single spoke will have a number of implications. For example; it will affect its opposite spoke and will also pull the rim slightly to the side.

When the rim is true, the mechanic should conduct a sound test of each spoke's tension. This test simply requires the mechanic to lightly tap each spoke (use the spoke wrench) and listen for a sharp ping sound--all of the spokes must sound the same.

Acceptable Run-Out Tolerance

The actual acceptable amount of run-out varies between manufacturers. Consideration must be given to the expected speed of the bike and the weight it will carry (heavy touring bikes with lots of panniers etc.).

Tips and tricks:

1) Adjustments to correct wobble or vertical movement of the rim should be made progressively and checked regularly

2) If, after adjustment, an adjustment made run-out worse, the mechanic should reverse his previous action and try to compensate by working on the opposite spokes

3) Use dry-erase marker pens to check for true. A light pressure will apply a mark that gets wider the further the rim is out of true at that point

4) To avoid having to place a lot of weights on the rim for balance after the tire has been fitted, the mechanic can check the rim's balance first and note the heavy spot (typically where the rim was joined). As the tire will also have a heavy sport, the mechanic can position the tire to counter it.