Wobbly or warped rims can hurt a bicycle's performance and make braking difficult, according to the Park Tool website. Over time, all bike rims require minor maintenance to straighten a slightly warped, "out-of-true" rim. "Truing" a wheel requires adjusting the spokes to evenly distribute spoke tension. Tightening or loosening spoke tension in a warped area realigns the wheel.
Truing the Wheel
Step 1
Remove the warped wheel from your bike and place it on the truing stand. A truing stand looks like the front fork of a bike and is mounted on a base. Also mounted to the base is a set of adjustable calipers. Truing stands can be purchased at a local bike shop or from online vendors for $60 to more than $200 in 2010.
Step 2
Gently spin the wheel to locate the warped area. Adjust the truing stand calipers until the warped side of the rim begins to scrape the "feelers." The "feelers" are symmetrically arranged extensions of the calipers that are used to measure the distance from each side of the rim to the end of each feeler. If one side of the rim is closer to one of the feelers than the other side of the rim, the rim needs to be adjusted.
Step 3
Using a spoke wrench, which you can buy at a bicycle store, adjust the spoke or spokes where the warped part of the rim touches the feelers. The spokes you tighten and loosen are determined by which side of the rim touches the feelers. On the side the rim that touches the feelers, tighten the spoke coming from the opposite side of the wheel hub so as to pull the warped area away from the feelers. Also loosen the spokes on the same side as where the rim touches the feelers. Use quarter turns of the wrench to avoid over-tightening.
Step 4
Incrementally readjust the truing calipers to the point where the feelers touch the now less-warped area of the rim, as you did in Step 2.
Step 5
Continue tightening and loosening spokes as needed to fully realign the wheel. Use smaller and smaller turns of the spoke wrench as the wheel comes closer to being true.
Tips and Warnings
- Warped wheels are not always caused by uneven spoke tension. Lennard Zinn, author of "Zinn and the Art of Road Bike Maintenance," recommends checking for rim damage, broken spokes and even loose hub bearings, which could complicate the repair. Zinn also suggests adjusting spokes in pairs when fixing a laterally out-of-true wheel.
- Don't attempt to repair extreme bends in a wheel by simply adjusting the spokes. It may require spoke tension that is beyond the manufacturer's specifications and lead to rapid deterioration of the wheel or a broken wheel.
Things You'll Need
- Spoke wrench
- Truing stand
References
- Park Tool: Wheel and Rim Truing;
- "Zinn and the Art of Road Bike Maintenance"; Lennard Zinn; 2005
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