: Pirelli P Zeros at autocross



danothemano
11-29-09, 10:30 AM
I had to throw away my stock tires (PS2s) after 6,000 street miles and four auto cross events which equals approximately 25 miles of ground pounding driving. However, I was able to watch the sidewalls on my front tires go away each run when autocrossing. I ran the fronts between 42-45psi and the rears between 37-40psi. I have tried all different psi when autocrossing and the car is so heavy that you have to keep them full or you will instantly roll your fronts over.

First off it is very hard to find good tires for 19" wheels for example, kumho ecsta xs are a very good high performance street tire and so are the bridgestone potenzas, dunlop star specs, hankook v12s, and falken azenis. However, I couldn't find them in the sizes we need for the car. Anyway, I decided to replace the ruined PS2s with Pirelli P Zeros (Just regular P Zeros, not Corsas or neros, etc..) and I went with 265 35s in the fronts and 295 30s in the rear. So I went one size wider and one size less profile front and back with a tire that according to tire racks test report is much grippier and ultimately faster on the track than the PS2s. So I should be faster :burn: around the same 1/2 mile autocross course with the pirellis than with the PS2s right? My results: fastest lap time on the PS2s 32.902 secs, on the pirellis 34.380 secs :mad2:.

As you can see from my results I am considerably slower around the course with my new wider tires :cookoo:. But it doesn't end there the back tires also dont hook up as well as the ps2s. DOES ANYONE HAVE ANY OPINIONS ON MY SITUATION HERE????? I can only come up with two opinons on my own: 1. Tire rack lied and the pirellis are an inferior tire to the PS2s. 2. I need an alignment more suited for high performance driving. Maybe the change in tire size exaggerated the need for an alignment think it needs negative camber front and back, toe in in the back, toe out in the front. I took tire temperature after making two runs and my tires were 89 degrees near the insides and 102 degrees near the outsides which is a much bigger gap/difference than I ever had with the PS2s.

Tony407
11-29-09, 11:12 PM
It sounds like you have a lot of opinions about what is going on, and while I can't say I've done the research you have, it really doesn't surprise me at all. The PS2s are arguably one of the best high performance summer street tires out there. I think most of us could have predicted your findings right from the start, regardless of what Tire Rack said. I did read the review you were talking about and it does appear that the Pirellis got better marks for grip but less for "overall handing" which went to the PS2s. Sounds ambiguous to me, and it might suggest a closer looking at their test methods.

Also, did you use the same pressure in the Pirellis as the PS2s? My initial thoughts are that you could conceivably run them lower because of the shorter profile, and this may help with getting them to hook up.

I really can't comment on alignment because I don't feel qualified.

I myself took the V with the stock PS2s to an autocross and got excellent results. I can't remember the pressures I used but not once did I feel like I was about to roll a tire. And I came with a few seconds of the best times at the track, set by a turbo Miata with significant suspension and differential mods.

Bottom line though is that the PS2 is a KICK ASS tire and well worth the small fortune they cost if getting quicker lap times is your goal. Is there a reason you went with the Pirellis vs. another set of PS2s besides the Tire Rack review?

Tony

GMX322V S/C
11-30-09, 02:22 PM
...I am considerably slower around the course with my new wider tires...While your Pirelli's are new, you're going to get more tread squirm vs. when you ran with your worn down PS2's...

danothemano
11-30-09, 07:41 PM
Is there a reason you went with the Pirellis vs. another set of PS2s besides the Tire Rack review?

Tony[/QUOTE]

Probably because I was so motivated to get better tires that I didn't stop and realize how good what I already had really was. YOU DONT KNOW WHAT YOU GOT..... TILL ITS GONEEEEEEEEE:violin:

Tony407
11-30-09, 07:51 PM
Is there a reason you went with the Pirellis vs. another set of PS2s besides the Tire Rack review?

Tony

Probably because I was so motivated to get better tires that I didn't stop and realize how good what I already had really was. YOU DONT KNOW WHAT YOU GOT..... TILL ITS GONEEEEEEEEE:violin:[/QUOTE]

Well, I'm right there with you. I'm tempted to try something else of comparable status next time to save on money. At $550 a tire, the PS2s certainly aren't easily affordable. A lot of people have gone with the Hankooks, but I'm still not convinced I'll be happy...similar to what you've been through.

Tony