964C4

I do 4 track events or so a year

Considering same track, same driver, same car, same all !

Please consider:

OEM wheels + OEM tyres (Bridgestone RE050A) I make my best lap time of 1 minute and 30 seconds

How much could I improve using OEM wheels or OZ Ultraleggera wheels with Michelin Pilot Sport Cups ? 2 seconds faster ?

Please comment, thanks !

StanThePorscheFan

Is everything else on the car fully track prepared? So much so, that now you are looking at the tires to shed some lap time? Seriously?
Not sure how much time you can save, tho.

Tcc1999

Are your driving skills so refined that you need to step up and "buy" better performance? Sorry, that was rude, there was probably a more polite way to say that. But to your question, there might be many things you could tweak to get those two seconds. Tires are a funny thing, one brand on a car set up in a certain way might perform better than on the same car set up a slightly different way. All things being equal, you'd have to buy the tires and try them out on your car - or keep your current tires and try different set-ups. Too bad, like ski demos, they don't have tire demos for cars. My track skills are probably a 4 on a scale of 10 (and that is being generous to myself) but if I were more skilled and knew where the car was limiting me that's what I'd focus on. Point being, maybe you'd get better, more specific advice about tires if you provided some input on your skill level and where you feel your car (tires) is/are limiting you.

964C4

Thanks, but 2 wrong / mislead replies

I am just curious to know that taking the same car, driver, same track, weather conditions, etc. what time improve can be had by switching to stickier tyres ?

GT3 and GT3RS come with Michelin Pilot Sport Cups, the reason is they have a lower treadwear and stick better to the surface, right ?

So, what time improvement do you think ?

Mike in CA

I've autox'd for many years on street tires, DOT R compound tires, and slicks. There's no question that, all else being equal, your times will improve with the R comps over the street tires. I'm not saying that tires are a cure-all for bad technique or poor setup, but a competent driver in a properly sorted car will achieve better times on the competition tires.

I got my 997.2 S toward the end of the '09 season and used my street tires (Pierelli P Zero's) for a couple of events. For '10 I acquired a set of 18" Porsche take-offs and fitted them with Michelin Pilot Sport Cups for autox. On a 45-50 second autox course, depending on the layout, the MPSC's are good for a 1 to 1.5 second advantage, which is a lot. They have shallower tread so they don't chunk like the full treaded street tires, with better and more predictable grip and turn in. One downside of these tires for autox (aside from their price) is that they work best in the 160-220 degree range which can be harder to achieve on a short autox run. For track use you would have no difficulty in that area. One thing to note is that the N spec MPSC's which come on the GT3's, for example, are a different tire than the normal MSPC. I don't have the exact spec on them but supposedly the "normal" ones have better grip but wear faster.

Bottom line, to answer your question, on a 1:30 road course, I think that an R-comp tire might easily be worth a couple of seconds.

964C4

You understood what I asked and your reply is appreciated, thanks !

Are 18" wheels better than 19" wheels for the track ? My car is also a 997.2...

PJorgen

Also depends on the track. Is there more speed to be gained in the turns or do you need a faster car on the straights?

Mike in CA

I think most people will tell you that they prefer the 18's. You will find that a wider selection of brands and sizes are available in 18" competition tires and they won't be as pricey. Wheels and tires in 18" sizes will be lighter than the 19's which is also important for handling. I think most people find that 18's in general are a little easier to drive at the limit, with less abrupt transitions than the lower profile tires. There was a video from a Japanese car test show where they drove 911's back to back on 18's and 19's to evaluate the differences and reached the conclusion that while it was possible to achieve slightly faster times on the 19's it was noticeably more difficult. Maybe someone has that link and could post it; I know it was on here quite a while ago. You could try to search the archives.

RonCT

Understand that the Porsche N rated Cups are not "real" cups, but rather a hybrid between summer compound and near-cup tread and sidewall design. When the N rated Cup came out, one of the Tire Rack guys posted photos and a detailed description of the new design and posted a side-by-side photo of the "real" 235 19" cup and the "faux" N rated version. The contact patch is greatly reduced with the N rated tire (rain channels are about 2x as wide). Porsche even wrote in some literature that they worked with Michelin to "reformulate" the tire compound to optimize cold and wet performance, which we all believe to mean reduced "warm track" performance in favor of better cold / wet performance.

I've driven real cups, N rated cups, RA1s, Corsas, PS2s, etc. on the track. I found the PS2 to be very similar to the N rated cup, while the "real" cup was superior in the warm / dry. 2 seconds might be close on a long track like Watkins Glen, maybe 1 second on a short track like Lime Rock.

1 second is so quick - basically the time it took me to type "type". No big deal and having a safety valve of better cold / wet performance is nice in the northeast when it's freezing cold in the early spring / late fall.

ADias

I heard today that a test was conducted with pro drivers on a track, driving Porsches with PS2 and PSC. Lap times were indistinguishable...

RonCT

I was curious so I ran some tests with my TraqMate and found the G loading (lateral and braking) were equal with both. Lead me to believe the compound in the N-specification "Cup" was equivalent to the PS2. Maybe more contact patch with the "faux" Cup tread than in the PS2, which would give the slight dry / warm advantage to the "Cup". 18" real cups are another story...

Mike in CA

I assume you're referring to N-spec MPSC's not the "real" Cup tires....

ADias

I think so.

Mike in CA

Would have to be, given the info we've had in a couple of threads recently. First, from Larry Cable's (Global Launch of the new Michelin Pilot Super Sport in Dubai) thread:


"The Super Sport is intended to deliver significantly better performance than it's predecessor the PS2 approaching that of the current Pilot Cup Sport, but with better wear and wet traction characteristics."


Then from R&T in the thread on the new Super Sport (Road & Track report on Michelin Pilot Super Sport):


"Compared to the Pilot Sport 2, the Super Sport laps about 1.5 sec faster on a racetrack, can stop almost 5 feet shorter from 62 mph in the dry, and stop nearly 10 feet shorter from about 50 mph to 5 mph in the wet."

So the "real" MPSC is still slightly quicker than Super Sport which is quicker than the PS2 it replaces. Certainly in line with my experience with the 18" MPSC's I have on my car and the PS2.
Regards

964C4

Wow, such important info was added since yesterday, thanks !