SON 28 FAT BIKE 6 BOLT ISO DISC BLACK HUB

Design and construction

A dynamo hub is a generator: magnets in the hub shell spin around a fixed coil on the axle and produce alternating current that a light or a charger turns into something useful. Schmidt's trick is efficiency; the SON 28 reaches full output at lower speed than any competitor and drags less when the light is off, which is why a SON wheel feels like a normal wheel. The hub is sealed so that air moves in and out only through a pressure-compensation system rather than through the bearings, which is why the bearings last for decades and why the five-year warranty covers them.

Because the front 28 fat bike dynamo has no freehub, it is the hub that asks for the least: a spin of the axle to check the bearings once a season and nothing else. The flanges, bearings and seals are the same as the rear's, the axle converts between the front standards with end caps, and the rotor mounts the same way. Choose it to match a rear of the same model, or on its own for a fork that needs a new front wheel.

How it rides

A fat bike on a SON 28 dynamo wheel has light and power whenever it is moving, which in a winter forest at 8 km/h is exactly when you need them. The drag is small enough to disappear under a 4in tire, the sealed hub shrugs off slush and salt, and the bearings last for years. It is the dynamo we recommend for fat-bike touring and winter commuting.

On the road or the trail the front hub's job is to disappear: spin freely, keep water out, and hold the flanges still so the wheel tracks where you point it. The front 28 fat bike dynamo does that with the same bearings and seals as the rear and none of the rear's complexity, and because a front wheel carries less load and no torque it stays true longer than the rear on the same rim. When the rear finally needs a look, the front usually does not.

Specifications

Which version this is

Version notes. 6-bolt rotor mount, QR 5x135mm, Thru Axle 15x150mm, 32h, about 410g, in black, silver. If your frame or fork uses a different standard, the other versions of the 28 fat bike dynamo on this site cover it.

Six-bolt is the original disc mount and still the most universal: any ISO 6-bolt rotor from any brand bolts straight on, rotors are cheap and easy to find anywhere, and the six-bolt flange is a robust, simple interface that has been on mountain bikes for twenty-five years. Centerlock rotors do not fit it.

Sizes, fit and compatibility

The Son Dynamo SON 28 Fat Bike 6 Bolt ISO Disc Black Hub comes in the drillings listed on this page in 150 x 15mm thru-axle spacing with a 6-bolt rotor mount. J-bend spokes in any gauge; we build most fat dynamo wheels with Sapim Race or DT Competition spokes and brass nipples.

It pairs with the HED Big Deal and Big Aluminum Deal, DT Swiss BR 710, Sun Ringle Mulefut and Surly fat rims in the catalog. Pick fat bike as your bike type in the configurator and it recommends a spoke count and lacing pattern for the offset.

Put it in a custom wheel

Build a custom wheel around the SON 28 Fat Bike 6 Bolt ISO Disc Black Hub — the link drops you into our Custom Wheel Program with this hub pinned, ready for you to choose the rest. It is set up for fat bike and MTB single-speed builds.

Building it at ProWheelBuilder

SON makes the 28 fat bike dynamo; ProWheelBuilder is an independent custom wheel builder in Georgia and not the manufacturer. The build is the same every time: measured ERD, spokes cut to the half millimeter, staged tensioning with a gauge, stress relief, a final true, and tubeless tape and a valve on request.

The configurator shows only rims and spokes that fit the 28 fat bike dynamo drilling, strikes through combinations that are not made, and prices the wheel live.