Tension, Retension, True, and Round the Wheel
You have a newly laced, very loose wheel, and now it is time to bring the spokes to proper tension and to true and round it.
You can also retension an old wheel. Simply loosen all the spokes, leaving the nipple attached enough to hold them on but very loose. It is best to start at the valve hole and loosen each nipple no more than half a turn, going around the wheel until all the spokes are loose. When the tension is low, you can turn more than half a rotation. Of course, you should replace any rounded nipple or damaged spoke.
Tension Standards
To do a good job, it is necessary to use a spoke tension meter. The Park tension meter TM-1. is the least expensive, under $75, and does an adequate job. You cannot judge spoke tension adequately by feel.
Spoke tension must be consistent throughout the wheel. The minimum standard is that each spoke must be within 20% plus or minus of the average spoke tension. A really good wheel will be within 10% plus or minus the average. If the wheel is not dished (front wheels without disc brakes) this standard applies to all the spokes. If the wheel is dished, the standard applies to spokes on the same side of the wheel. On dished wheels, spoke tension is greater on the side of the shorter spokes (drive side on rear wheels, rotor side on disc brake wheels). The spoke tension on the drive side of the rear wheel is more important than on the left side.
What level of tension is best? There is no uniformly right answer. Don't tighten so much the nipples may strip. High tension could damage some rims or hubs, but the nipples will probably strip before a rim or hub is in danger. The higher the tension, the stronger the wheel. Rear wheels need more tension than fronts. Dished wheels need more tension than non-dished wheels. Heavy riders, abusive riders, and people who break spokes need high spoke tension.
For riders who break spokes, I suggest a 36 hole, triple cross, 2.0 mm (14 gauge) spoke, brass nipples, double wall rim rear wheel. My tension goal is 125 kilograms force (kgf) (as measured on my Park TM-1) on the drive side. The non-drive side tension is normally 60-70% of the drive side.
True and Round Standards
A wheel should be true to within 1 mm. A really good wheel as zero tolerance on true.
A wheel should be round to within 2 mm. A really good wheel will be round to within 1 mm. In any event, the wheel must be round enough for the brake pads to safely engage.
Most Important Advice
The most important advice is--G-O S-L-O-W. Make the adjustments in small stages, especially the first stages. Don't look at your sloppy wheel and decide to bring it to tension quickly--big mistake!
Work in a pattern. Start at the valve hole and work a tiny bit on each spoke until you are back at the valve hole. Rotate the first nipple 1/4 to 1/8 rotation, go to the second, and so on.
This will be very hard if you don't have experience truing wheels. Read the section on wheel truing, to understand true, round and dish.
The procedure is:
1. Place the wheel (without the tire mounted) in the truing stand. Always mount a dished wheel the same way. I put the dished side on my right.
2. With a nipple driver or flat head screw driver, tighten all the nipples a uniform amount, but not enough to cause any resistance at any nipple. I tighten the nipples until half the spoke threads are left showing. It is crucial that you approach the point where the nipples start to show resistance very slowly.
3. Notice how far your wheel is away from being true and dished at this point.
Hopefully you have a truing stand that is centered. In a centered truing stand is adjusted so a correctly dished wheel's rim will be equal-distanced from each truing stand caliper. With a good, tuned truing stand you can easily see how far you are out of true and dish at the same time.
This wheel should be adjusted to the right for dish.
If you don't have a truing stand that is centered, you can tell how far out of dish you are by flipping the wheel over so what was the right side is now on the left. A dished wheel's rim will be the same distance from the truing stand caliper both ways.
4. Notice the bend in the spokes where they exit the hub flange. Gently push and pull the spokes against the hub flange to take the extra bend out.
5. Tighten the nipples a very little bit more. I usually tighten the nipples until 1/4 the threads are left showing. However, do not tighten the spokes so much that there is any resistance at any of the first 3/4 of the spokes as you progress around the wheel. If the first spokes in the rotation show resistance, the last spokes will be too tight at this stage.
Notice how far your wheel is away from being true and dished at every stage. If the wheel is out of dish at the early stages of tensioning, tighten the nipples on the side the rim needs to go, and skip the nipples on the other side.
Try to tighten the nipples the same amount. On a dished wheel, try to tighten the left nipples the same and the right nipples the same, but the left does not need to be the same as the right.
6. Continue step 5, rotating each nipple less each time (1/4 to 1/8 rotation) until the last few nipples in the rotation show resistance. Your goal is to have all the nipples showing the same resistance against the inside of the rim while the spoke tension is still very loose. During this step, if the wheel is out of dish, bring it closer to dish by tightening the nipples on the side the rim needs to move more than the other side. Notice the true, too, and address the true as you are tightening the nipples.
7. Now that all the nipples are against the rim, but with the spoke tension very loose, with very small nipple rotations, bring the wheel to dish.
8. With the spoke tension still very loose, bring the wheel to true.
9. Now bring the wheel to round. It is much easier to round a wheel with very loose spoke tension. It is almost impossible with high spoke tension. If you have much spoke tension at all, it is best to back the nipples off some to reduce spoke tension.
Move the truing stand calipers so they are below the rim and just touching the highest place. Your goal is to bring all the rim to within 2 mm (preferable 1 mm) of round. Rotate the wheel. Where the rim touches the truing stand caliper, tighten the spokes no more than 1/4 turn at a time. Tighten spokes on each side the same amount. Spread your forces--for example don't tighten 2 spokes 2 rotations--tighten 4 spokes 1 rotation instead. Go slow.
Work on round a few minutes, then go back to true and dish. Keep each parameter in mind as you work on the other. Go back and forth. Make small improvements on each parameter without screwing up the others.
Spread your work over the wheel. If there are two bulges in round, improve one a little and work on the other one a little, and go back to the first. In between revisit true and dish.
Trying to go fast will screw you up.
10. Drop a little lubricant at the base of each spoke, so it will drip down in the hole. This will help the nipple slide in the spoke hole and reduce spoke wind-up. I use Triflow wet lube.
11. Hopefully your wheel is reasonably round, true and dished and is still soft in tension. Notice each parameter and the spoke tension. It is a good learning tool at this point to record your spoke tension. Measure and record each spoke's tension. (A left column and a right column, rows for spokes 1-16.) Find the sum of each column and divide it by the number of spokes on each side of the rim. This is the average spoke tension for that side of the wheel. Multiply this amount by .8 and by 1.2 to find 20% plus or minus the average spoke tension. Look at the tension for each spoke--is it within 20% of the average? If not, go back and work on the tension. Sometimes it's best to start over--loosen all the spokes and retension the wheel.
12. Bring your wheel to tension. Starting at the valve hole, rotate each spoke 1/8 turn, going around the rim. Work slow. Often check dish, true and round. Before approaching your target spoke tension, measure and record tension. If a spoke is too tight, loosen it and tighten its neighbors on the same side and/or loosen its cohort across the rim.
Periodically relieve the spoke tension. Grab adjacent parallel spokes and squeeze them in your fingers. Or stick a screw driver handle between each pair of spokes and bear down. This seats the nipples on the rim, straightens the bend in the spoke at the hub flange, and releases spoke wind-up.
Your wheel is finished when you can relieve the tension and it is properly tensioned and still round, true and dished.
13. Behold your work. Is it true to 1mm? Is it round to 2 mm, preferably 1 mm? Is it dished? Is the spoke tension to within 20% the average on each side (Repeat step 11)?
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