The stunningly light RZR is the first product to come out of Reynolds' new ultra-premium Composites Studio division and the numbers are indeed jaw-dropping. Our tubular test pair weighs just 896g without skewers (364g front, 532g rear, 34g skewers) – and no, none of that's a typo – and the asking price is a hefty US$6,000/£4,999.99 per pair (and neither is that).
For those that can stomach the cost, there's at least a lot of technology included in the RZR's materials, design, and construction. Carbon-boron fibre blends are used throughout the 46mm-deep rim, spokes and hub shells for both lighter weights and higher strengths gram-for-gram and it's all bonded together for an integrated one-piece package that's still factory-repairable in the event of crash damage.
Though clearly extremely light, aerodynamic performance is also a key goal. The rim profile is nominally similar to Reynolds' standard 46mm rim for a good punch through the wind in most conditions but the added 'swirl lip generator' on the RZR rim's trailing edge supposedly reduces drag even further. The added micro-region of turbulence is said to help the rejoining of the air that was split by the tyre and rim while also improving handling in crosswinds, too.
Lateral stiffness is provided with the two outermost flanges and their radially laced spokes, but all drive torque is tranferred through the central flange
NACA-profile (National Advisory Committee for Aeronautics) spokes are used throughout but in a unique zero-tension configuration. Under load, the hubs are effectively suspended from the rim while the spokes below are allowed to flex to prevent shattering. Lateral rigidity is provided by the widely set flanges front and rear while torque is transferred through the Tune-made freehub body by a unique third flange on the rear hub, directly in-line with the rim.
Carbon fibre is even used for the hub axles, too, with the rear being supported in the shell by three cartridge bearings to stifle flex.
So does it all work? We'll find out soon enough. Watch this space.