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WHAT YOU NEED TO KNOW
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
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
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.
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:
Warps often occur, because spokes have stretched or become loose over time, or because of accidents.
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.
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.
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.
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.
|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).|