Why the fastest TT helmet for one rider isn't the fastest for every rider
Aerodynamics in time trialling is never fixed. Head position, arm angle, shoulder width, fatigue, course profile — all of it shifts how air moves over the helmet. ABUS and Swiss Side started development with that reality and built the testing programme around it rather than ignoring it.
Four representative riding positions — Head Up, Head Down, Flat Arms, and Angled Arms — formed the basis of every CFD run and wind tunnel test. The goal was robust aerodynamics: consistently low drag across the positions a rider actually moves through, not a peak achieved when perfectly still in a lab.
Across testing, the Timeshifter delivered 10.5 to 14.7 W of savings versus the GameChanger TT 1.1 at 50 km/h, depending on position. ABUS optimised the ventilation at the same time — the Forced Air Cooling channels deliver a cooling improvement of up to 13% over the reference helmet.
What ABUS × Swiss Side means in practice
Swiss Side brought decades of aerodynamics experience from Formula 1 and professional cycling. ABUS contributed its helmet safety expertise and close relationships with elite athletes. The partnership gave both teams access to independent, validated data at every development stage — CFD, wind tunnel, and velodrome results compared objectively rather than selectively.
112 CFD simulations. 194 wind tunnel runs. 39 velodrome test runs.
The Dual Visor Concept
The Timeshifter ships with a Narrow Visor (smoke). A Wide Visor is available separately — and the choice is an aerodynamic decision, not just a visual one.
Rider anatomy and cockpit setup affect which visor creates less drag for a given position. Riders with a broader upper body or more open arm setup may find the Wide Visor faster; riders with a compact position may prefer the Narrow. ABUS recommends aero testing to confirm the right choice for your specific setup. A Cut Visor is also available for extreme positions where cockpit clearance is the limiting factor. All visors attach magnetically.
Shell sizing: M and L present the same aerodynamic profile
The external shell dimensions are identical for sizes M and L. Fit adjustment happens via the inner shell. A rider in a Medium presents the same aerodynamic profile to the wind as a rider in a Large — no penalty for a smaller head.
Race validation
Marlen Reusser (Movistar Team) won the UCI World Championship individual TT in Rwanda, 2025, wearing the Timeshifter: 38 km, 43:09.34, a 51.89-second margin over second place. Jonas Schomburg recorded the fastest bike split at Challenge Roth the same year. Both athletes were involved in development — real race feedback shaped the final design.
AeroGain's independent assessment
We tested the Timeshifter on 15 athletes against the strongest TT helmets currently available. The aero advantage ABUS measured in their tunnel held up in real-world conditions. We were impressed — and we are not easy to impress.
Optional accessories
Wide Visor: clear (€129.95) · smoke (€139.95) · mirrored (€149.95)
Narrow Visor (replacement): clear (€129.95) · smoke (€139.95) · mirrored (€149.95)
Cut Visor: clear (€129.95) · mirrored (€149.95)
