Chicago restaurateur and famed chef, Curtis Duffy, knows a thing or two about combining carefully-selected ingredients into a critically-acclaimed product. His eating establishment, Grace, is one of only three Michelin three-star restaurants to ever earn the prestigious, top-level rating in the Windy City and is one of just 15 eateries in the U.S. that currently hold the sought-after ranking.
It’s a similar story in the world of tires.
Laurent Huc, compound designer at Michelin in France, started with 3,000 different compounds during development of the company’s latest ultra-high performance (UHP) tire, the Pilot Sport 4S (PS4S). Huc and the rest of the team knew they had to master the recipe for the PS4S.
Michelin’s outgoing, 6-year old UHP tire — the Pilot Super Sport (PSS) — holds similar success to Curtis Duffy in the world of awards and accolades. We traveled to Palm Springs, California to see if the French company mastered the mixture for the new black rubber donut, upping the game beyond the PSS.
First, it’s important to clarify the somewhat perplexing name of the new Michelin tire. The ‘4S’ in PS4S does not mean it’s a four-season (all-season) tire. The PS4S is Michelin’s 4th-generation Pilot Sport UHP summer tire, carrying on the legacy of the original Pilot Sport, the Pilot Sport PS2 and the Pilot Super Sport.
To add to the confusion, Michelin also has the new Pilot Sport 4. That tire doesn’t hold the same ultimate performance focus as the PS4S and is exclusively a European-market tire, outside of a handful of OEM applications. That’s why there is an ‘S’ in ‘PS4S,’ signifying a level of performance beyond the Pilot Sport 4, similar to Porsche’s badging scheme for the 911 Carrera S versus the standard 911 Carrera.
“We had some pretty demanding requests from product marketing (for the PS4S),” said Carl Driver, senior product development engineer at Michelin. “They wanted better dry/wet braking, lap times and rolling resistance. They also wanted to maintain wear — the 30,000-mile warranty. Take everything we had with the PSS and expand it — that’s the PS4S.”
Only two of the original 3000 compounds made it into the dual-compound PS4S. 60% of the compounds tested were for the inner portion of the tire — primarily for wet weather. New functional elastomers (rubber) are utilized, which are patented and manufactured in-house by Michelin. The outer portion of the tire features carbon black material, increasing dry grip by managing and dissipating heat. A variable contact patch reduces stresses and pressures on the tire, improving grip further.
Our validation took place at The Thermal Club — a private country club track facility just outside picturesque Palm Springs, California. We started on an autocross course — a surprisingly wet autocross course. You can almost guarantee dry conditions in the desert but, surprisingly, the skies opened shortly before our drive. Given that one of Michelin’s key goals was to expand wet performance beyond the PSS, we wonder if the company made a deal with Mother Nature. Either way, the PS4S did not disappoint.
The rear-wheel drive BMW 340i test vehicle impressively resisted understeer and easily transferred the robust torque of the turbocharged inline-6 into forward motion on the drenched pavement. A direct comparison to the Bridgestone Potenza S-04 Pole Position revealed that the PS4S carried more grip and outright pace throughout the course.
Further Michelin highlights include overall consistency and confidence, as well as braking performance. We casually measured wet braking from roughly 60 mph on the PS4S versus the Bridgestone and the Michelin came out on top by an average of 12 feet. Michelin’s more-scientific internal testing reveals the PS4S beats the Potenza by 2.2 meters (7.2 feet) when braking on wet pavement from 80 km/h (just under 50 mph).
A brief run in a BMW M4 on a wet section of the road course at The Thermal Club validated the PS4S’s rain skills. Again, grip was plentiful and, when the limits of adhesion were reached, the Michelin UHP tire gave us plenty of warning, with a progressive drop in its hold on the rain-soaked circuit. Like on the autocross track, the PS4S also allowed brisk acceleration out of slow corners without significantly triggering the traction control. Keep in mind that the BMW M4 is known to overwhelm the rear tires at low speeds, even on dry pavement.
Our final leg of our PS4S review was a road drive through Joshua Tree National Park in a Ferrari California T and Mercedes-AMG GT S. The pace was slow and the loop relatively short, but it allowed us to confirm that the PS4S is a smooth and responsive tire on public roads with no glaring flaws or issues. We found turn-in to be a particular highlight on that portion of the test. Our thoughts on road noise will have to wait until we’re on more familiar pavement and we’ll have to take Michelin’s word on wear, at least for now.
The PS4S goes on sale in North America in March, with similar pricing to the PSS. “We’re launching with 35 sizes,” said Driver. “We’re making 19 sizes in the U.S and importing the remaining 16 from Europe. We currently have 60 active O.E. (original equipment) developments and some are already launching.”
We look forward to spending more time behind the wheel of a PS4S-equipped vehicle on our local roads and race tracks but the initial experience in Palm Springs appears to confirm that Michelin is still one of the best chefs in the business of tire preparation.