How to True (Align) Bicycle Wheels

In just a few minutes you can learn the basics of wheel alignment. Never again pay bicycle professionals for what you can enjoy doing for yourself.

First a bit of terminology:

Wheel: The entire assembly consisting of tire, inner tube, rim strip, rim, spoke nipples, spokes, and hub.

Tire: The rubber that meets the road.

Innertube (or inner tube, or tube): The thin bag that seals the air into the tire and wheel.

Rim Strip: A thin layer that protects the innertube from being punctured by the spoke nipples.

Rim: The outer metal ring of the wheel.

Spoke nipples: Threaded nuts that attach the rim to the spokes.

Spokes: Metal rods connecting the rim to the hub.

Hub: The assembly of bearings and other equipment in the middle of the wheel.

Hang your bicycle up on a repair stand, a car carrier, or with some rope attached to your rafters, so you can easily spin the wheels.

Let's start by understanding how spoked wheels work. Grasp a couple of spokes on one side of the wheel near the brake, and squeeze them together where they cross. Notice that the portion of the rim near the brake moves closer to a brake pad. If you squeeze the spokes on the other side, the rim moves toward the other brake pad. By deflecting the spokes as you squeeze them, you are effectively shortening them momentarily. So, if you could permanently shorten the spokes you have squeezed, the wheel's rim would be permanently moved toward a brake pad along that section of the wheel. And, of course, if you shorten spokes on the other side of the wheel, the rim would move toward the other brake pad.

You adjust the length of the spokes by turning the spoke nipples. You can tighten and loosen them with a spoke wrench ($2 - $6 at any bike shop).

Spoke nipples are right-hand threaded, like most things in life. This means you turn them clockwise to tighten, or counter-clockwise to loosen, the same as a jar lid. This is as seen from the top of the spoke nipple at the rim. It is almost as if the spoke nipples were lids on tall, thin, metal jars - the spokes.

Slowly spin your wheel, and you'll probably see an area in which the rim is too close to one brake pad. Stop there. Loosen a couple of spokes on the side where the rim is close to the brake pad, and tighten a couple on the side opposite. This will pull that portion of the rim into proper alignment. Start by turning each spoke nipple only 1/4-turn or so.

Repeat this process until the wheel is aligned to your satisfaction. Many professional bike mechanics refer to 'aligned' as 'true.' And they call 'aligning' a wheel 'truing a wheel.'

For best results, have a bicycle mechanic watch when you first attempt to align a wheel. If you try it without a mechanic, and the wheel starts to get worse rather than better, you might want to stop and seek expert help.

Special considerations:

If you have a wheel with loose spokes, Tighten the loose spokes, and the spokes opposite the loose ones, so that the alignment won't be worsened. Starting at the valve stem, tighten each loose spoke only ¼-turn or so, and go around the wheel as many times as necessary until they are all properly tightened. Make final adjustments to the alignment when the spokes are all tight.

How do you know how tight the spokes should be? The best way is to visit a bike shop, and just squeeze the spokes of several new bike wheels. Get a feel for how much spokes flex when they are tightened correctly. You might also flick them with your fingers to see how properly tight spokes sound.

If the wheel is excessively bent, more than ½-inch (12mm), the rim, or perhaps the entire wheel, should be replaced. For a field repair of a very bent wheel, you can loosen all the spokes, bend the rim into nearly the right alignment by carefully stepping on it, or hitting it with a rubber mallet, retighten the spokes, and then adjust the alignment. Otherwise, if you depend on spoke tension to pull a very bent rim into alignment, the wheel will be weak, possibly resulting in spoke breakage or a sudden, dangerous collapse of the rim.

If a wheel has broken spokes, they should be replaced before attempting alignment. If you are on a long ride, and don't have replacement spokes, you may be able to borrow a few from another portion of the wheel, or the bike's other wheel. If a spoke has broken at the hub, you can cut it shorter, bend a curve in it, hook it into a spoke crossing, and reattach it to the rim. That's not ideal, but better than having a missing spoke.

If you think there is any risk that the rim strip is not properly positioned, or that the spokes may be drawn all the way through the spoke nipples, you will probably want to remove the tire and tube before adjusting spokes. Otherwise you may have to fix a punctured innertube.

Most wheel alignment problems are lateral, meaning side-to-side. A wheel can also be eccentric - the distance from the rim to hub may vary. The usual variation of this is 'flat spots.' A local flat spot can occur when someone has ridden over a rock or curb, especially with underinflated tires. That's a short flattened area of the rim. A larger flat spot can occur from not tightening and loosening spokes together. In other words, as you tighten some on the left side of the wheel, you should loosen some on the right, and visa-versa. To repair a large flat spot, simply loosen all the spokes along the flat spot, and tighten all the others in the wheel. To repair a local flat spot, remove all the spokes at the flat spot, hit the rim outward with a mallet, then reattach and tighten the spokes. Only a mild local flat spot should be repaired. You don't want to risk riding with a cracked rim.

Often local flat spots also flare outward where a rock has been hit. You can carefully squeeze these back into position with a rag-covered pair of pliers, or hit the side of the rim with a mallet. Again, for safety, be careful not to attempt to repair a rim that is so badly damaged that it should be replaced instead.

This sounds rather enjoyable, doesn't it? Yes, it is a good feeling to repair something yourself. However, you might be concerned about making your first attempts on your own bike. If so, you can always buy a broken bike at a garage sale for $5 or $10, and practice aligning its wheels. For that matter, you can practice making all sorts of other repairs on that bike, too.