There are times when it is necessary to straighten a bicycle wheel after a wreck or because of bumpy road conditions. It is also possible that you bought a new or used bike that has a wheel which needs adjustment. Truing a wheel takes patience and a little bit of knowledge, but it is something that most cyclists can do on their own with few tools.
Wheel Truing: Things You Need
Ideally you would have a truing stand which is a special rest for your bike wheel which allows you to work with fine adjustments of the spokes to set the wheel straight. However, if a truing stand is not available, you can still do a good job working with the wheel on the bike.
You also need a spoke wrench the right size for your spokes. If you have only one bike, or all your bikes have the same size spoke nipples, you can buy a spoke wrench that is just the right size. These are much easier to work with than a spoke wrench with multiple sizes. The round or triangle wrenches with multiple sizes are handy because you can work on various size spokes, but somehow they always turn in your hand and you lose the correct slot.
You will also need the wheel that needs truing and extra spokes if you are having to replace some or suspect that some will break in the truing process.
Wheel Truing: Basic Concepts
A wheel is has spokes from both sides of the hub radiating out to the rim. These spokes pull the rim from one side to the other. The hub does not move in the same way that the rim does. The hub can be made to shift from left to right, or vice versa. But this is a shift in relationship to the whole wheel assembly. That shift is called dishing. What we are concerned with when truing a wheel is how the rim moves from left to right in relationship to itself. You are able to pull just one section of a rim the direction you want without shifting the whole rim to one side.
By tightening (or tensioning) a spoke nipple, you are pulling the rim at that point over to that side. When you loosen (or de-tension) a nipple, you are allowing the other side to exert more pulling power on the rim. It is possible to have a true wheel with loose spoke tension and with tight spoke tension. The idea is to get the wheel true with the proper tension. If it is too loose the wheel will be unstable and will easily twist. If the tension is too tight it is possible to collapse the wheel, break the spokes or make a taco or pretzel shape from the wheel.
The goal is to get the wheel straight with similar tension on all of the spokes. There are spoke tension tools that you can use to determine if your tension is too tight or too lose. For most purposes, with experience, you can tell if the spoke tension is too much or not enough.
It takes a little bit of thinking to tighten and loosen spoke nipples the right way. They tighten and loosen just like any other normally threaded nut onto a bolt. The difficulty is that we are essentially tightening the nut from the opposite side than we normally do. To help understand this, imagine you are looking from the rim to the hub with the spoke wrench in place. From that position, grab the wrench and turn it clockwise to tighten, and counter-clockwise to loosen.
Wheel Truing: Getting Started
If you are using a truing stand you will place the wheel in the stand without the tire or tube. If you are truing the wheel while it is on the bike, you can do it with or without the tire and tube. It is easier to see what needs to be done if the tire is not on the wheel when truing it. However, if you are just doing a slight adjustment, then there is no need to pull the tire off for straightening the wheel.
Squeeze all the spokes to release the tension that may be built up between the spokes where they cross. If your spokes are rusty or have not been trued in a while, then you may need to put a drop of oil on the nipple where the spoke enters the nipple. Another drop of oil should go in the hole where the nipple comes out of the rim. This will help the nipple turn easily and, hopefully, prevent you from breaking a spoke.
Wheel Truing: Fine Adjustments
There are two different adjustments that should be made when truing a wheel: radial and lateral adjustments. Radial adjustments are what is needed when you spin the wheel and can see the wheel jump up while looking from the side. Lateral adjustments are what is needed when the wheel wobbles left to right when looking from the front or back.
Radial Adjustments With Truing Stand: Set the gauge in place so that the out of round section of the wheel is bumping it. Adjust one spoke from each side at the point where the wheel is touching the gauge. This should be no more than 1/4 turn at a time. By adjusting one spoke from each side you will pull the rim towards the hub without making a lateral adjustment. Work your way around the wheel pulling down all the high spots. Be careful to not end up with three or four spokes that are considerably more tight that all the others.
Radial Adjustments Without Truing Stand: If you are making radial adjustments, you will need to remove the tire from the wheels. Place something across the forks near where the brakes are that can give you an indication of where the rim "jumps." This will be your gauge to tell you where the adjustments need to be made. Adjust one spoke from each side at the point where the wheel is touching the gauge. This should be no more than 1/4 turn at a time. By adjusting one spoke from each side you will pull the rim towards the hub without making a lateral adjustment. Work your way around the wheel pulling down all the high spots. Be careful to not end up with three or four spokes that are considerably more tight that all the others.
Lateral Adjustments With Truing Stand: Set the arms so that one spot on the rim is touching one arm when the wheel is spun around. As an example, let's say that your rim bumps the arm gauge on the left side in one section. This means you need to pull the rim to the right. Using your spoke wrench, tighten the spoke in the middle of the high section 1/4 turn on the right side. Then loosen the spoke before and after that spoke 1/4 turn on the left. Keep checking for any other high spots on the left side and work them out by tightening and loosening as necessary. Remember that just tightening on one side will not necessarily work out the high spot. You also need to loosen the corresponding spokes.
After you have worked out all the high spots on the left, move the truing stand's gauge on the right into place and work out all the high spots on that side. Keep working back and forth until the wheel is true. You will need to check your radial trueness too to insure that all the lateral adjustments did not pull the rim out of round.
Lateral Adjustments Without a Truing Stand: Place something on the left side of the forks that you can use to see, or feel when the wheel bumps out further in one spot than the rest of the rim. This is called a high spot. Let's say that your rim bumps the object you have set up as your gauge on the left in one section. This means you need to pull the rim to the right. Using your spoke wrench, tighten the spoke in the middle of the high section 1/4 turn on the right side. Then loosen the spoke before and after that spoke 1/4 turn on the left. Keep checking for any other high spots on the left side and work them out by tightening and loosening as necessary. Remember that just tightening on one side will not necessarily work out the high spot. You also need to loosen the corresponding spokes.
After you have worked out all the high spots on the left, move the gauge from the left side of the forks to the right side and work out all the high spots on that side. Keep working back and forth until the wheel is true. You will need to check your radial trueness too to insure that all the lateral adjustments did not pull the rim out of round.
Wheel Truing: Finishing
There is one other element of truing a wheel that is called dishing. This is how far left and right your hub is in relation to the rest of the wheel. On a front wheel the hub should be in the center. On a back wheel adjustments have to be made to center the rim and tire over the center of the hub and freewheel assembly. We are assuming that your wheels were properly dished before you started truing them. Dishing is more of a concern when building wheels from scratch. Therefore it will not be covered here.
Check to make sure that you don't have whole sections of spokes that are considerably tighter than others. If you have very tight, or very loose sections, then you run the risk of the wheel quickly going out of true, or worse, collapsing.
If after your best efforts to true a wheel and it is no better, or has gotten worse then there is still hope. Start by loosening all of your spokes to a similar tension slightly looser than they would normally be. Start again with the truing process. It is possible to get this right, but it does take practice and patience.
Truing a wheel is a great skill to know. You don't have to be a master at it. When you are sitting on the side of the road with a wheel that won't spin because it won't pass through the brakes, you at least know how to get it reasonably straight again.