Unveiled to the public at the 2011 Eurobike show, Bontrager’s reworking of the Aeolus wheel range promised state-of-the art cycle wheel aerodynamics thanks to a rim profile – labelled D3 – that works well with either the tyre or the rim as the leading edge of the combined profile as it hits airflow.
Labelled Dual Directional Design or D3, the idea has resulted in a fat rim profile 27mm wide at the widest point and with a notably blunt, rounded nose. This, combined with a standard 23c tyre, is claimed to be effective in reducing drag and instability over a wide range of yaw angles – sidewinds in cycling terms – whether the tyre or rim is leading as it hits airflow.
The D3 series will comprise four tubular rim depths: 35mm, 50mm, 70mm and 90mm. Of them, the 35mm and 50mm (D3 and D5) are already in production. Here we have the 50mm rim in clincher format; it is the first clincher to be put into production and the only model so far available in the UK.
Made in the US using Trek’s OCLV carbon-fibre moulding technology, the rim is entirely structural, unlike its predecessor, which sported a thin carbon-fibre cowling attached to a conventional box-section carbon-fibre rim.
Weighing a claimed 700g front and 850g rear, the wheels feature 18 front and 24 rear DT Aerolite spokes with locking nipples laced to hubs by DT Swiss with the firm’s DT240 freehub body internals. The standard freehub body is Shimano and SRAM-compatible with a Campagnolo-type version available to order.
The wheels are sold separately if required and are supplied complete with wheelbag, valve extender, carbon-specific brake blocks to fit Shimano-type shoes and skewers. Prices are £874.99 for the front and £1024.99 for the rear.