AJ:

I remember reading about how small the contact area of tire actually is in Auto Motor Sport many decades ago. This is why RC is always so concerned about the correct OEM N01 or factory spec tire fitment. I have come around to this thinking now as well and specifically specify N01 tires for my Porsche and R01 tires for my R8. We are speed controlled in Canada but there is something about having best contact area you can get.

 

 

I give you two examples:

PZero (Shelby GT500): Wanted to have this tire for my former Mustang GT500 Shelby (2014), tuned to around 760 hp). Stock Vmax was already 322 kph. Car came standard with some sorts of semi-slicks Goodyear, which were pretty bad in rain and during cold temperatures. Pirelli issued a certificate for my car, limiting the top speed to the stock Vmax of 322 kph but under one condition only: They asked for 3.4(!) bar tire pressure in all four tires. With a tire pressure of 3.4 bar, the car was undriveable, not only at lower speeds but especially at higher speeds over 200 kph. Like driving on raw eggs. The only driveable tire pressure was around 2.6 bar, it was not perfect (perfect was 2.4 bar). According to Pirelli, driving with a tire pressure of 2.6 bar, the top speed had to be limited to 260 kph.

Now the "fun" part: Many Shelby GT500 drivers I knew drove the same PZero, even with tuned cars (and most of them do easily close to 340 kph Smiley) and used the 2.6 bar tire pressure. Insane to ignore a tire manufacturers recommendation. Smiley

Michelin Cup 2 R01 (Audi R8 V10 Plus): Optional tire which comes with the Audi Racing rims, it can also be ordered without the rims. Standard tire was a PZero R0 (I think, I do not remember anymore). The switch to the Cup 2 R01 improved the dry performance but not as much as I expected. It was surprisingly good in the wet, which was something Audi had done with their own "mixture" to keep the tire safe in the wet. The difference between the Audi version of the Cup 2 and the standard Cup 2 was a different one though: The sidewalls of the Cup 2. They were stiffer in the rear because of the extra weight of the R8 engine and the mid engined setup. I talked to a Michelin engineer who was there to promote these tires. He warned me of using standard Cup 2 instead. 

If people think that the manufacturer "ratings" are just a marketing ploy, they are wrong. They aren't. If you ever have the chance to talk to a car engineer from Porsche, Lamborghini or even McLaren, do it and talk tires. You'd be surprised.

This is the new PZero Corsa PCZ4 L1 tire set I just received for my Performante. Car was originally equipped with the L.

The new Evo uses PZero PZ4 L, not PZero Corsa.

The new Corsa L1 is supposed to be very close to the Trofeo R but with highly improved wet capabilities. A new Trofeo R is apparently in the marking as well.

I am so curious how good or how bad this new tire is. Will get it installed while I enjoy studying the STO. Smiley Smiley

 

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RC (Germany) - Rennteam Editor Lamborghini Huracan Performante (2019), Mercedes GLC63 S AMG (2020), Mercedes C63 S AMG Cab (2019), Jeep Grand Cherokee Trackhawk (2019 EU)