Pirelli P Zero Race SL-R: New Aero Road Tyre Tested & Reviewed | Cyclingnews

Italian tyre manufacturer Pirelli unveiled its new P Zero Race SL-R tyre today, positioning it as a top-tier road racing tyre designed to minimize aerodynamic drag, reduce rolling resistance, and maximize grip, and handling. The company claims a 2-watt normalized aerodynamic gain at 45km/h compared to its existing P Zero Race RS model.

The launch follows a period of testing with professional cycling teams using prototype versions of the tyre, according to Pirelli. Development of the SL-R involved leveraging aerodynamic expertise and computational fluid dynamics (CFD) simulation techniques borrowed from Pirelli’s Formula 1 and MotoGP divisions over an 18-month period. Over 14 iterations of the tyre were analyzed using proprietary techniques, including unsteady flow simulations.

Pirelli product manager Carlo Di Clemente explained that while the rider accounts for 80% of aerodynamic drag, up to 5% can be attributed to the front wheel and tyre. This percentage increases with the growing trend of wider tyres mounted on wider rims, which present a larger frontal area to the wind. The company focused on reducing flow separation at the tyre-rim interface and maximizing the “sailing effect” to improve aerodynamic performance.

The P Zero Race SL-R incorporates Pirelli’s patented PAAS (Pirelli Advanced Aerodynamic System) technology. This involves adding rubber to the tyre’s sidewall, increasing its width above the rim and smoothing the transition between tyre and rim. Pirelli’s research indicates that optimal aerodynamic performance is achieved when the tyre’s widest point is positioned at a specific height relative to the rim, a profile that varies depending on tyre width.

Di Clemente stated that other aerodynamic approaches, such as vortex generators used by competitors, can be less effective at lower yaw angles and may increase rolling resistance. Narrower tyres, while reducing frontal area, often require higher inflation pressures, negatively impacting rolling resistance and comfort.

Pirelli’s wind tunnel testing, conducted across four different facilities, demonstrated a 2-watt aero gain over the P Zero Race RS, normalized over yaw angles up to 20 degrees at lower speeds. At higher yaw angles, the gain increased to 5 watts. A measurement at a 15-20 degree yaw angle showed a 15-watt saving, attributed to the SL-R’s slick tread pattern, as opposed to the grooved tread on the P Zero Race RS.

In addition to aerodynamic improvements, Pirelli claims a 10% reduction in rolling resistance with the SL-R, equating to a 2-watt saving per pair of tyres. This is achieved through a new LiteCore 120 TPI tubeless-ready casing, which Pirelli says is more supple, enhancing ride comfort and grip. Despite the lighter casing, the tyre retains a puncture protection belt, with expected mileage comparable to the P Zero Race RS.

The P Zero Race SL-R is initially available in 28mm and 30mm widths, with a 32mm option scheduled for release in October. The 28mm tyre has a claimed weight of 275g, 15g lighter than the P Zero Race RS, though testing by Future magazine showed a pair weighing 286g and 288g. The tyre is priced at £94.99 (approximately €99.99) for the standard version and £99.99 for the Team Issue version with yellow logos.

The tyre has already seen competitive use, contributing to two stage wins and the points classification at the 2026 AlUla Tour, as well as Stage 7 of Tirreno-Adriatico, ridden by Lidl-Trek’s Jonathan Milan. Mathieu van der Poel also reportedly used the tyres at Milan-San Remo.