THE TUNNEL DATA

Our exclusive wind-tunnel test delivered some fascinating results (we’ll go through them in-depth next issue), with some helmets only delivering the aero goods at certain speeds and angles (Scott), others consistently behind the pack (Endura and Poc) and some continually in the lead (Specialized and Giro).

The data produced gave us stats for the Coefficient of drag (CdA); Power to achieve the speed (Watts); Speed at the baseline power (km/h); Time to complete 35km and 45km at 35km/h and 45km/h; and the time behind the best performance of the Kask Mistral TT lid. Here we’ll show you the average time difference at both positions, yaw angles and speeds behind the Kask Mistral TT over a 40km bike leg.

The scores were: 1. Specialized Evade 2 (+32secs); 2. Giro Vanquish (+37secs); 3. Scott Cadence Plus (+46secs); 4. Bell Z20 Aero MIPS (+46secs); 5. Poc Ventral (+54secs); 6. Endura Pro SL (+55secs). The B’Twin 500 road helmet meanwhile was +49secs.

Regardless of yaw, speed or position, the top two helmets were the Specialized Evade and Giro Vanquish. The curiosity is the Scott Cadence, which performs well at 35km/h and the 10° yaw angle, but is less effective at the higher speed of 45km/h at 0° yaw.