By incorporating specially-ramped divots in the shoulder of the otherwise normal road bike tire tread, DT Swiss says the spinning tire itself can supplement the ‘sailing effect’ that they have shown significantly reduces drag in high-end aerodynamic wheels. Now, in a much simpler and lower-cost product – an aero tire can likely provide even more reliable aerodynamic gains…
DT Swiss aero road tire concept patent

Filed together with aero expert Jean-Paul Ballard of Swiss Side, who has worked on all of DT Swiss’ aero-optimized wheels since their ‘Road Revolution‘ back in 2016, these new tires have been refined down to a simple design with a relatively small number of aero depressions in their shoulders that have demonstrated significant aerodynamic benefits in the wind tunnel.
Key to DT Swiss’ description of this patented aero tire tech, is that it’s more consistent than you typically see with aero wheels AND it is equally as highly effective at the lower speeds that most amateur cyclists actually ride (while still maintaining high efficiency at high speeds, too.)

Specifically, with average speeds of 37.5km/h, according to the invention a sailing effect can already be utilized in many situations, wherein air impinging obliquely from the front is utilized for generating propulsion. The invention enables such a sailing effect not only with high ( relative ) speeds of 45km/h or more, but also already with average speeds of 37.5km/h and even with low speeds of 30km/h. This is difficult to achieve, and none of the competitors’ products achieved as much.
How do aero depressions in a tire make you faster?

Much like the dimples and textured elements in some road bike frameset & wheel designs, the idea is that the aero divots in the tread tire create a boundary layer of turbulent air directly next to the spinning tire, allowing oncoming airflow to pass more smoothly over the tire, without detaching.
DT’s patent filing defines that the aero depressions are offset away from the center of the road bike tire’s tread to not affect straight-line grip or rolling resistance. And these aero elements then only a small position of the shoulder tread – between 5-25% of the surface in a line along the edge of the tire (1-8% of total tire surface area). In fact, the patent filing indicates that wind tunnel testing showed that adding more closely spaced or a greater number of divots actually reduced the aerodynamic improvements, as does any other significant tire ‘roughness’.

What does all this mean for bicycle aerodynamics?

What’s next? Road bike tires from wheel maker DT Swiss?

