Radial and Lateral Trueness

There are 2 critical measurements to ensure that the final wheel set meets your needs. The first is its radial trueness, essentially 'is the wheel round'. The rims are constructed to be round within the manufacturer's tolerance, however by applying unequal tension to the spokes it is quite easy to change shape of the wheel, hence as the wheel is built it is important to keep the tensions relatively equal on each side of the wheel. The second is lateral trueness, this is a measure of the degree the rim moves from side to side when the wheel is spun. As a cyclist you will likely have experienced the issue that breaking a spoke, or hitting a pot-hole can cause, when suddenly you are slowed by the rim rubbing as the wheel rotates. We use our German built P&K Lei 250 Special truing stand to true our wheels to +/- 0.15mm  radial and lateral tolerance.

Wheels are built so that the rim is central to the frame back and front. On rear wheels because of the cassette there will be an offset where spokes on the non-drive side are longer and the drive side shorter. The net effect is that the tensions on each side are different: typically tension on the non-drive side may be 2/3rd that experienced on the drive side. The effect of this can be that on poorly tensioned wheels the spokes on the non-drive side loosen over time. This effect can also be experienced on some front disc wheels. To counter this some manufacturers offer rims with offset nipple holes to even out the spoke tension on drive and non-drive side. 

Rim Tension

Adding tension to the wheel creates a stiff robust assembly and reduces the tendency for the nipples to unwind as you ride. Tensioning the wheel correctly will ensure the trouble free longevity of the assembly. Rim manufacturers usually specify a recommended or maximum rim tension, typically this might be 120 Kgf or 1200N per spoke. If the tensions vary significantly from spoke to spoke (on the rear wheels there is usually a difference between drive side and non-drive side tension) there may be one or many spokes that over time will work the nipple loose, the wheel will go out of true, and this will be immediately obvious if you have rim brakes. To counter this we equalize tensions across the wheel using a tension meter, we aim to build our wheels to a tension within -5% of the manufacturers specified tension where specified. We also use a low strength thread locker (e.g. Loctite 222) applied to the spoke thread during construction to further reduce the risk of spoke unwind.

Truing and Tension Measurement

To ensure that we build consistent wheels we have invested in a number of tools to help get it right. Park Tools have supplied us with an industry standard truing stand and tension gauge. This tends to be used to do the preliminary truing for wheel builds or to straighten wheels during maintenance.  

For final truing and tensioning during wheel builds we have invested in high precision P&K Lei Professional Truing Stand and calibrated tension meter. This equipment enables accuracy down to 0.025mm deviation laterally and radially. These readings can be taken concurrently, so you can instantly see the effect as you adjust the tension and position of the rim, enabling our stated tolerances of +/-0.15mm to be achieved. Not only does this equipment work really well it looks great in the workshop too!