Wheel stability

A 32 or 36-spoke wheel built with a SPEEDHUB is stiffer than a conventional 36-spoke derailleur rear wheel — roughly on the level of a 48-spoke tandem wheel. There are three reasons.

1. Symmetrical flanges. The rim sits centred between the two hub flanges and the spokes run at the same angle on both sides, so every spoke gets the same tension. On a derailleur wheel the cassette makes the flanges asymmetric: the drive-side spokes have to be tensioned much harder.
2. Enough preload. A stable wheel needs at least 1,000 N of spoke tension with the tyre inflated, at least 1,300 N without. On a strongly asymmetric derailleur wheel that is not always reachable: the drive-side spokes would go above 1,200 N, which endangers the rim’s nipple seats.
3. Large flange, large bolt circle. Thanks to the large flange, two-cross spokes sit at roughly the angle of three-cross spokes on a low-flange hub. And the larger circle means less force per spoke for the same driving force (torque = force × lever arm).

The measured spoke forces

The highest spoke force riding out of the saddle, with similar gearing on both wheels (SPEEDHUB gear 4, 48/16, 2.52 m; derailleur 36/30, 2.47 m). Preload in brackets.

Property	SPEEDHUB 500/14	8-speed derailleur hub
MTB, one 80 kg rider
Spokes, dropout width	32, 135 mm	36, 135 mm
Flange offset from centre (left / right)	30 / 30 mm	37.3 / 20.2 mm
Highest spoke force (left / right)	963 / 963 N (700 / 700 N)	972 / 1,475 N (600 / 1,105 N)
Tandem, two 80 kg riders
Spokes, dropout width	32, 135 mm	48, 145 mm
Flange offset from centre (left / right)	30 / 30 mm	31.3 / 24 mm
Highest spoke force (left / right)	1,206 / 1,206 N (700 / 700 N)	1,196 / 1,409 N (700 / 912 N)

Despite two riders, the tandem’s derailleur hub does better than the solo MTB wheel — thanks to 48 spokes and less asymmetric flanges. Still, the SPEEDHUB wheel’s highest spoke force is lower: 1,206 N against 1,409 N.

When 36 holes?

A SPEEDHUB wheel is stiff enough with 32 spokes in every case, tandems included. The 36-hole version exists so that, outside Europe and North America where 32-hole rims are rare, you can still replace a rim on the road.

Disc brakes, radial lacing

A disc brake side needs no different lacing pattern. Radial lacing on the left is possible in theory without a disc brake, but we advise against it: it throws away the main advantage, every spoke working equally. For building practice see Wheel building and spokes.