ENDURA D2Z AEROSWITCH

£349.99 Is this two-in-one racing helmet worth the outlay?

Thanks to an exhaustive R+D process in the wind tunnel, which even included making life-sized models of pro riders, the D2Z Aeroswitch is claimed to be the fastest TT helmet in the world. Even more fascinating is the removable tail section, which you can take off to use it as an aero road helmet.

With the tail it has a wide shape, the reason being that this is faster in a wider range of yaw angles, according to F1 aerodynamicist Simon Smart who Endura recruited to develop their Drag2Zero range. Affixing the tail is simple, with three clip-in attachment points, and it sits very flush with the rest of the helmet. There’s also a striking multi-coloured visor that attaches with strong magnets, and on the road it provides superb clarity and glare reduction without steaming up. If the weather takes a turn you can simply flip it over, and it even sits smoothly on top of the shell for minimal drag losses.

The core of the helmet is Koroyd, a mesh-like material that’s said to give better impact protection than EPS foam and improved ventilation. Cooling is indeed fantastic on the Aeroswitch, among the best we’ve tried on a TT lid, and in its aero road guise we never overheated. Yes, the tech comes at a price, but as you’re getting two helmets in one, the outlay goes further. So for competitive triathletes with money to spend, the Aeroswitch is worth the investment. JS endurasport.com