Test Day With Casper Stornes For The EZ Gains BTA Bullet

In December 2025, EZ Gains organised a wind tunnel testing session for Casper Stornes, the current Ironman World Champion. This testing session had the purpose of recording Casper’s CdA for his current set up and then improving on this baseline with some new aero tech.

Some of the associated companies that appeared included Pinarello, ABUS, Q36.5 and EZ Gains. Testing is done at the Silverstone Sports Engineering Hub using their high spec cycling wind tunnel.

The testing protocol was done based on Casper’s 2026 race calendar, analysis of these courses and previous pro times was conducted to get a scope of which speeds and yaw angles to target.

Components for testing included: trisuits, calf guards, helmets, TT bar configurations, BTA set up and rear hydration configuration.

If its possible to save a few watts for each section, it’s easy to see how we can save Casper a possible 10–20 watts. To limit the variables affecting test runs, Silverstone has a camera system to help the rider keep their position aligned.

Analysis from these tests are done at 45km/h for consistency and that aligns best with the expected race speeds. Q36.5 is Casper’s new sponsor and they brought some new development suits. From these, many performed better than his previous setup aerodynamically.

They also brought some calf guard variants which also tested faster than his previous pair. One of the tests that was important to Casper was making sure his non-wetsuit set up was aerodynamically optimised.

One of the priorities for the test session was helmets. ABUS had brought a new helmet for Casper to test which ended up being faster than his previous one.

First we changed the angle of the TT bars, which benefits the aerodynamics, however, this is a change that should be considered alongside comfort after several hours on the bike.

Regardless of which tilt angle used, the 3D printed attachment would be aerodynamically superior, this item also increases storage for nutrition in the front end.

Casper already uses the EZ Hydro-Gains, but we wanted to see how optimised we can get it. From several previous tests, we knew that a double bottle is faster for most people.

In each optimisation, a few watts were saved, compounding to a large total watt saving.

Overall, it was a fantastic testing day with Casper and everyone coming away happy.

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