Wheel truing basics - Bike Magic

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Wheel truing basics

From hearing people go on about wheel truing you’d think it was some sort of black magic, with practitioners relying on mysterious incantations and foul-smelling potions to transform the wobby wheel back to miraculous straightness. Well, it isn’t. There’s a knack to it, but there’s nothing mysterious about the process. Anyone can true a wheel. It’s a good idea not to start out by trying to straighten out wheels made with swanky parts, though. Try and find an older, tattier wheel to practise on, then move on to your good stuff when you’re confident

1. There’s only one essential tool for wheel truing – the spoke key. There are plenty to choose from although the Spokey shown here is our favourite for reliable nipple engagement and ease of use. The important thing is to make sure you’re using the right sized key. Most wheels have 14 gauge nipples, while lightweight wheels may have 15 gauge nipples. Using the wrong sized key is a quick route to rounded-off nipples aplenty, which is as bad as it sounds.

2. The only other thing you need is some way of telling which way the wheel’s wobbling, and where. The best way of doing this is with a wheel truing stand – this is a Park TS-7. A truing stand lets you sit comfortably, see what you’re doing and generally make a better job of things. The downside is that they cost money (lots of money in the case of the heavy-duty professional models) that you might not wish to spend for the sake of occasional wheel-truing duties.

3. The cheap-and-cheerful alternative to a pukka truing stand is your bike. Stick it in a workstand so the wheels will spin and there you go. Use a rubber band or some Blu-Tac to stick some kind of pointer (an Allen key or a pencil or something) on the stay and you’re sorted. If you’re out in the middle of nowhere and have rim brakes, you can just use them to show where the wobbles are. Whatever you use to true the wheel, it makes things a lot easier if you take the tyre off first.

4. Wheels are pre-stressed structures – they rely on tension in the spokes to keep them in shape. The tension in the spokes varies as the wheel rotates and as it rolls over things. The idea is that the static spoke tension is sufficiently high that even when loaded the spokes don’t actually go slack. If they go slack the nipples can unwind and the spokes become loose, which makes the wheel go out of true. So to make it straight again, we need to adjust the spoke tensions which we do by turning the spoke nipples.

The first thing to get your head around is which way to turn them. To tighten a spoke nipple, you need to turn it clockwise looking at the spoke end-on, ie from where the tyre would be. Although don’t actually look at it end-on, as occasionally a spoke will break as you tighten it and half a spoke may ping through the rim at high speed.

5. Right, down to business. Put your wheel in your chosen stand and move the pointer so it just clears the sidewall of the rim. Spin the wheel and peer intently at the gap betwixt rim and pointer. With any luck you’ll be able to see that it’s generally straight with a couple of wobbles in it. Spin it back and forth until you’ve identified the biggest wobble. It doesn’t matter if it’s wobbling towards or away from the pointer.

6. You’ll notice that the spokes are staggered either side of the centreline of the rim with the spokes coming from the right hub flange being offset to the right and vice versa. To bring the wobble back into line, first check to see if one of the spokes near the wobble is a lot looser than the others. If it is, tighten it until it’s somewhere near and check the wobble again.

To move the rim over to the left, tighten the spokes on the left side 1/4 turn and loosen the ones on the right by the same amount.
Work on four spokes at a time, two in each direction. Try to keep all the nipples aligned so that the spoke key is either perpendicular or parallel to the rim – it makes it easier to judge how much you’re adjusting them. If your wheel has butted spokes, they’re likely to twist as you tighten them. To get around this, turn the nipples slightly too far and then back them off to the desired position.

7.Spin the wheel again and the wobble should have got smaller. If it’s still the biggest wobble, repeat the tightening/loosening thing until another wobble becomes bigger. Repeat the procedure, always working on the biggest wobble. In theory if you tighten and loosen spokes by equivalent amounts the wheel should stay round, but chances are that it’ll develop a bit of a ‘hop’ with high and low points around the circumference. So when the lateral trueness is looking good, move the pointer so it’s across the rim and check for up-and-downiness.

Correcting hops is a similar theory to correcting wobbles, except that instead of tightening and loosening opposing spokes, you tighten (or loosen) left and right spokes together. If part of the rim bulges outwards, tighten the spokes at the bulge. If part of it drops inwards, loosen them. Start at the highest (or lowest) point and adjust the spokes either side of that point 1/2 turn and the ones outside of those 1/4 turn. Spin the wheel, check and repeat.

8. Once your roundness is good, go back and check for wobbles again. If they’re both good, make sure the wheel’s still dished right, that is, that the rim is exactly in the middle of the hub as it ought to be on nearly all bikes (there are some bikes with asymmetric rear ends that need the rim to be aligned differently but these are both rare and a pain in the bum, so we’ll ignore them). The easiest way to check this is by simply taking the wheel out of the stand, flipping it over and putting it back in. The rim should be the same distance from the pointer both ways around. If you’re lucky enough to have a dishing tool (supplied with some truing stands), then you can use that.

9. If your wheel is significantly off to one side but straight, simply go all the way around the wheel tightening spokes on the side towards which it needs to move and loosening them by the same amount on the other. Start and finish at the valve hole to ensure you do all of them. Adjust by 1/4 turn at a time unless it’s miles out. Keep checking and repeating, then once it’s correct go back and check trueness and rounditude.

10. The last step is to go around the wheel grasping pairs of parellel spokes and squeezing them hard – gloves help. This is vital on a newly-built wheel with new spokes as this does all sorts of clever and useful things that you can’t see. On a just-trued wheel it may not do anything if you’ve managed to avoid spoke twist as you adjust them, but doing this will make any twisted spokes untwist. This’ll make the wheel go out of true again, but better now than the first time you ride it. Go back and correct any errors and repeat.

Here’s a few handy hints and things worth remembering about wheel truing:

  • Make small adjustments, and be methodical.
  • You won’t have to make any adjustments smaller than 1/4 turn.
  • Tighten any very loose spokes first.
  • Always work on the biggest errors.
  • If there are any dings or dents in the rim, they’re going to make life considerably more difficult, so sort them out before you start. Small inward dings can be gently straightened out with pliers or an adjustable spanner. If you’ve bashed a rock and splayed the sidewalls outwards, you may be able to squish them back by putting a bit of scrap wood either side and clamping the whole thing up with a G clamp. If you find you’ve got an untreatable ding, it’s new rim time…
  • Rear wheels (and disc fronts) have different spoke tensions each side. This doesn’t usually make much difference when correcting trueness, but getting hops out on an eight or nine speed wheel requires adjusting the right spokes twice as much as the left ones.
  • If the wheel makes various pings and pops when you first ride it after truing, you got some spokes twisted. Now they’ve straightened out you’ll need to true it again.
  • Practice on shonky wheels first.

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