Wheelbuilding Tutorial– Part 3:Truing

This tutorial describes how to build a bike wheel, aimed at the novice wanting to build their first wheelset. The tutorial is broken down into the following:

Part 3: Truing

Initial Truing

    • Put wheel in truing stand
    • Using nipple driver, or electric drill with custom nipple bit, to drive nipples onto spokes with nipples up to edge of thread (no thread showing)
    • Add a drop of tri-flow of liquid lube to base of each nipple at the rim
    • Tighten each spoke with two full turns with spoke wrench (Note: it takes a while to get used to which way to rotate the wrench to tighten or loosen the spoke. Looking down on the nipple from the hub, rotating the wrench counter-clockwise will tighten spoke, driving the nipple farther on the spoke).

Radial Truing

Radial truing makes the wheel round, getting rid of high and low spots. Using the feeler gauges of the truing stand, put them on the outer edge of the rim, the edge where the tire will come in contact with rim. As you rotate the rim, high and low spots will be identified. Since the wheel is still not fully tensioned, most of the work will be done by tightening up the high spots (where the hub bumps up against the feeler).

    • Tighten/loosen 4 spokes at a time to get rid of high/low spots
      • 1/4 turn for two spokes; 1/8 turn for two next outer spokes
    • Hard to get rid of spot at seam

Lateral Truing

Lateral truing is the “side-to-side” truing. Move the feeler gauges of the truing stand close to rim and look for places where the wheel is out of true. Since the wheel was never trued, it may be difficult to determine what is too far left vs too far right. It’s not too critical since dishing, see below,  will bring the rim and hub into proper alignment. Some pro’s will pluck the spokes to get an idea of relative pitch.  The lowest pitch is the loosest and likely needs tightening to bring the wheel into true (Note: the DS and NDS spokes will always have a different pitch since the DS is always tighter).

    • Tighten spokes to get wheel true by looking at or listening to the feeler rub on the rim.
    • Pluck each spoke on each side to get even to tensioning
    • Tension on DS will be higher than NDS

Rinse and Repeat

  • Double-check radial truing
  • Double-check lateral truing

Dishing

The hub must be centered in the rim (the center of the hub must be in the same plane as the rim). Or another way to think about it:  the same amount of hub must be above and below the rim, when on its side. Since the hub flanges on a rear hub are not the same distance to the locknuts, where the dropouts engage, because of the space required by the cassette and disc, the wheel must be “dished” to get the hub centered.

Checking the dish

  • Using the dish tool, place it on the wheel (legs touching the rims) and press the gauge down onto the face of the hub lock nut (not the end axle).
  • Flip the wheel and check where the gauge is relative to the hub lock nut of side two.  One of three possible outcomes: 1) the hub will touch the gauge at the exact height  as side one (highly unlikely), 2) there will be a gap between the gauge and the hub, or 3) the hub will stand proud and the legs of the dish tool will rock back and forth (a gap at the rim).
  • For result two, note which side the gap is on (likely the DS) and proceed to dishing steps below.
  • For result three, retract the gauge and repeat the measurement,  pushing the  gauge against the hub lock nut, and then flip the wheel to the first side and measure the gap at the hub. Proceed with dishing.

Dishing the wheel

The idea is to move the rim relative to the hub by tightening and loosening spokes. Tightening spokes on one side (or loosening spokes on the opposite side) will move the rim toward that side of the hub. An easy way to think about it is to tighten the spokes on the side opposite from the side with the gap (Gap on NDS, tighten DS).  Note: Because of the angle, half of a turn on the DS equals a whole turn on the NDS

  • Starting at the valve hole or key spoke, loosen the NDS a full turn and tighten the drive side a half turn.
  • Add more lube if the nipples are tight
  • Recheck the dish and repeat (Usually a half-turn on the will take care of a ~2mm gap)
  • Recheck the radial and lateral truing

Final Tensioning and Finishing

  • Bring the tension on the drive side up to around 21-22ish (scale of the Park meter)
  • Pre-Tensioning
    • Put the wheel on a 2×4 and pressed gently on the edges of the rim
    • Rotate 1/4 turn and press again
    • Flip the wheel and repeat
  • Recheck the lateral and radial truing
  • For tubeless setup, add rim tape and valve

Building the Front Wheel

For the front wheel, the disc front hub is asymmetric compared to a non-disc front hub (but much less so compared to the rear hub) the spoke tensions will be different for each side (“DS” = disc side and “NDS” = non-disc side). But given the small amount of asymmetry, the length of spokes are nearly identical. Thus, the procedure for building the front wheel is nearly identical to the one described for the rear hub.

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