Straighten Wheel

Introduction

This article is for:

making good distortions caused by everyday use - not wheel building.

WHAT YOU NEED TO KNOW

PRECONDITIONS: a truing stand, or somewhere to spin the wheel and observe the amount of any side to side movement of the rim

TIME: 1 hour

DIFFICULTY: Adjusting the spokes is easy. Deciding what spokes to adjust and how, needs some thought

APPROACH

Make many small adjustments, and gradually bring the wheel true.

STEPS

1. Is the problem really a warp?

2. Set up a truing stand

3. Inspect the wheel and replace broken spokes

4. True the wheel: basic process

5. True the wheel: adapt basic process

Approach

Make many small adjustments, and gradually bring the wheel true.

The key to straightening a wheel enough to keep you on the road is to:

work gradually - make a small adjustment, and then check that the result is a small change in the right direction.
If so, make another small adjustment and check again, and so on; and
plan each adjustment i.e. Think, then do! Leaping in with a big adjustment might make matters worse.

1. Is the problem really a warp?

Problem	Action
a warp: a minor, side-to-side deflection of the rim. The rim appears to 'bulge to one side' as it rotates	you can fix. Mark the warped section of the rim with chalk, and read on.
the rim is deformed in another way e.g. the rim sides spread apart, or are squashed together; hub not centred: the wheel goes up and down as it spins	contact a shop for advanced truing. You might need a new wheel.
the tyre is deformed	buy a new tyre.
drop outs do not hold the wheel securely	a new 'skewer', new wheel or new drop outs

2. Set up a truing stand

You need to set up a truing stand to clearly see how straight or warped your wheel is.

A purpose-built truing stand is ideal but a new one can cost more than a new wheel. The next best thing is to turn the bike upside down. The bike is supported on its saddle and handle bars, and the brake blocks provide reference points, or "marks", to indicate the amount of side-to-side movement in the rim.

In the picture below, the section of rim that warps too close to the upper brake pad has been marked with white chalk.

To identify warped sections (here indicated by white chalk), rotate the wheel and watch for deflections: a) before the warp, b) warped section and c) after the warp.

A warped rim. Note how the marked section of the rim warps up towards the break block

A warped rim. The section after the warp

3. Inspect wheel and replace broken spokes

To plan the necessary adjustments, first feel overall spoke tension

Feel spoke tension: Work around the wheel, and squeeze sets of spokes as if you were playing a harp. Then a answer the following questions:
1. Overall, do the spokes feel loose or tight?
2. Is spoke tension constant, or do some spokes feel looser or tighter than others?
3. Where are the loose or tight spokes in relation to the warp?
Warps often occur, because spokes have stretched or become loose over time, or because of accidents.
Replace any bent or broken spokes: Remove the tyre, inner tube and rim tape (see Puncture / flat tyre page). On rear wheels, also remove the cassette (block of gears) (see Replace cassette page).

Unscrew the spoke nipple from the rim-end, and then pull out the spoke through the the hub. Insert a new spoke and tighten the nipple so that the spoke is just as tight as others in the wheel.

Use a spoke key to screw/unscrew nipples. Do not over-tighten, or you might induce new warping.

4. True the wheel: basic process

Find the warp: Rotate the wheel until the greatest warp is adjacent to your marker. One side of the rim will be up against the brake block, with a larger than usual gap on the other side.

Look at the spokes near the warp. Note that they are attached to different ends 'sides' of the hub
Pull the rim over: tighten on the side of the gap: Identify the 2 spokes nearest the point of maximum warp attached to the hub on the side of the gap. Tighten these spoke by turning the nipple 1/8 turn clockwise. This pulls the rim back towards the centre line of rotation.
Let the rim ease over: loosen on the side of the bulge: Then identify the 2 spokes nearest the point of maximum warp attached to the hub on the same side as the bulge. Loosen these spokes, turning the nipple 1/8 turn anti-clockwise. This allows the rim to ease back towards the centre line.

To straighten a wheel, tighten spokes that are too long (on the side of the gap), and loosen spokes that are too short (on the side of the bulge).

Spin to confirm a small improvement: Spin the wheel and check you have straightened the rim by a small amount in the desired direction. You adjust the rim by less than a single millimeter each time you tighten and loosen opposing spokes, so you will probably need to repeat this process several times, to slowly bring the wheel back into true.

Note how, in the picture, the warped section of rim (marked in white) no longer warps towards the upper brake pad as in the previous figure.

It is easy to get mixed up, and to tighten spokes that need loosening, or turn nipples in the wrong direction. So take it slowly.

An equal distance from the rim to each brake pad indicates correct alignment.

5. True the wheel: variations on the basic process

The basic truing process assumes that, overall, the spokes in the wheel are about tight enough. But overall, the spokes in your wheel might be too tight or too loose.

Spoke Tension	Adaptation
overall, too tight	loosen 2 spokes on the side touching the brake block by ¼ turn. (No need to tighten any).
overall, too loose	tighten 2 spokes on the side of the gap by ¼ turn. (No need to loosen any).

Results

A true wheel feels stable - no wobbles