Bike wheels

Repairing bent wheels (called truing) can be one of the most difficult tasks one can do on a bicycle. If the rim is bent, or it's noticed that it is coming close to touching a brake pad, your wheel probably needs to be trued. Bringing the rim back into balance takes attention to detail that's mostly learned from building wheels in the first place. Patience is key, so if you're ready to bring that wheel back from the dead, here are some tips:

• Get a truing stand - the wheel can sometimes be trued while the bike is flipped over, but it just simplifies working on the wheel. Truing stands help notice slight imperfections that would otherwise be overlooked still in the frame dropouts.

Take a deep breath and don't rush anything. If there is a small flaw in the rim, you can find it by shining a light on the rim. In the reflection you will be able to find where the smooth stops and the trouble starts. Before messing with any spokes, try to hit the rim lightly with a rubber hammer to flatten the bump. Remember that you are working with very light metals, and overcorrecting can give more headaches than you might be ready for. Be gentle.

When corrections are made to a small part of the rim, it affects the geometry of the whole thing. Work around the rim making even, small turns of the spoke nipples. Constantly check that spoke tension is even with your fingers. They should bend only under significant pressure. Broken spokes will be apparent.

One thing to consider is that if the rim is severely dented, simply tightening loose spokes will only further deform the rim. Use a hammer to get the rim as close to round as possible before tightening spoke nipples. When a loose spoke is found, sometimes it is helpful to check the adjacent spokes at the same time. Covering more spokes makes a more uniform, round area of the rim. 

And finally: don't be a hero. If you have made many adjustments at very small increments and the wheel just doesn't seem to come into balance, take it to a professional. Solving the problems early and without too many adjustments will keep from further weakening the rim.