These prototype wheels from Williams Cycling are the first disc-compatible carbon cyclo-cross tubulars we've gotten our hands on. We were sent them by company president Keith Williams to whet our appetites.
They have a couple of unique features, the first being a 130mm spaced rear hub from Taiwanese manufacturers Chosen. With four bearings and a three-pawl freehub, it's said to weigh 270g. Up front is a 120g cartridge bearing hub. Both carry six-bolt IS rotor mounts.
The second promising feature is the carbon rim made by Taiwan's Gigantex. It's 38mm tall and has a tire bed that measures 22mm across (24mm OD), following the trend of wider tubular rims – for comparison, Zipp’s 45mm-tall 303 Cyclocross model measures 27.5mm across (OD) – which are said to better support the tire and offer a larger gluing surface. The rim is compatible with cantilever brakes and has a claimed weight of 375g.
The marble finish is achieved using horsehair and it's purely aesthetic; the rims are compatible with cantilever brakes as well
Williams’ first-round prototype package is assembled with DT Swiss Competition 1.8/2mm double-butted spokes, with 28 laced two-cross at the rear and 24 laced radially up front, which is admittedly questionable. Williams is still testing lacing patterns and spoke diameter. His biggest concern is wheel flex due to the narrow spacing of the front and rear hub flanges and how to deal with the braking forces.
The package weighs 1,586g (711g front, 875g rear) – roughly 3/4lb more than Zipp 303s. The prototype set does not have a target price or estimated on-sale date. That said, we expect the wheels to keep step with the brand’s economical pricing; all of Williams' spoked carbon wheelsets are priced at US$999, regardless of depth or tire type (tubular or clincher).