Specialized Propero 4 road bike helmet: Aerodynamics and ventilation in 5 colours

According to the press release, aerodynamics took centre stage in the development of the Propero 4. The shape is "inspired by the shape of the S-Works Evade 3." The ventilation openings have also been optimised to enable a "high internal airflow". The manufacturer calls this micro channelling: "We have installed small micro channels, each offset by 2 mm, which swirl the airflow throughout the helmet and thus ensure a continuous, refreshing airflow." Specialized explains the principle as follows: "Micro channelling works like a tumble dryer. Just as clothes are turned in the drum so that every fibre can dry completely, Micro Channeling ensures continuous air circulation in the helmet. Hot air flowing out draws in cool air." Other manufacturers have also promised optimum aerodynamics and the best ventilation - TOUR has not yet tested the helmet.

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We have therefore not yet tested the aerodynamics either. According to Specialized, the tests in the wind tunnel showed that the Propero 4 is four watts faster than the S-Works Prevail 3, which corresponds to a lead of 15 seconds over 40 km at an average speed of 45 km/h.

In Germany, the helmet is available for an official retail price of 190 euros. There are five colour variants - including helmets in white and black.

Propero 4 Sizes and weights

• Small: 270 g
• Medium: 290 g
• Large: 320 g

The bike helmet is equipped with the Mips Evolve safety system. In our Crash test we took a close look at the MIPS security system in 2023.

This is how MIPS works:

The function of this inner shell is to allow some additional rotational movement of the helmet shell in the event of an oblique impact - as is typical when falling over the handlebars, for example. This reduces the likelihood of brain damage, which occurs when the skull rotates so quickly that the inert mass of the brain cannot follow and blood vessels tear during the shearing movement between the skull bones and the brain. According to medical experts, the transition from mild concussion to severe head injury is fluid. This means that you should do everything possible to reduce the strain on the brain in the event of an accident.