Track tires

OK, I just came from Mid-Ohio. I have the "new" Michellin PS2's on the C4S. They suck. Softer side walls make for a great street ride, but they really roll over when pushed. It doesn't even require much pushing. I even pumped the tire pressures up to where they get real greasy by the second lap, and they still roll over bad. Granted, I'm running stock camber and could use more negative camber, but they suck nevertheless. Had to drive back home in the middle of the night to pick up my Dunlop SSR's. Great tires, BTW, but no longer being made. I'm just going to keep these tires for street use only, and probably go back to my P-Zero's for combined street and occasional track use in a pinch. I'm down to probably 2 DE days with the Dunlops. According to Tire Rack, I have three choices. There's Michelin Pilot Sport Cup and Pirelli Corsa in C4S sizes, and Hoosier A3S05 in C2 size. I saw a lot of the MPSC's on the track, and reading reading about the Hoosier seems to indicate they are more for autocross than the long track. I've heard Toyo RA1's are good, but can't seem to find them on-line. What do you guys think?

try kumho rcomp series.... v710...

no exp on khumos i used toyo's on c2, as far as i know, toyo ra1 doesn't have sizes for c4s. these do last a long time and you can drive them on the street even when wet, as long as you have some tread on them mpsc are great, very sticky when dry, gets you about 1000 track miles. there are many different types of hoosiers. some heat up quick for autox, some are designed for tracking use. though they shouldn't be driven on the street and they last about 200 track miles. very very sticky on track haven't used corsas yet. something is wrong with you tire pressure on the PS2. they are very very good on street and on track as well. my wore evently and has a lot of stick too. i start at 32f/32r cold aiming to hit 38f/40r hot for track use. they are some of the BEST street tires i have had and really works well on track too.

Here are my experiences: 1. The Hoosier AS is a no-go for track use. It's an autocross tire and heats up really quickly and won't be durable on track. If you want Hoosier, you have to go with the RS model. It's not durable either, but it is made for track use. It has a tendency to be very quick, then falls off mid session, so you have to back out a little, then it finishes strongly. It's not good for more than about two weekends, if that. It's also brutally unforgiving of flat-spotting if you don't run ABS. Two or three lockups can actually puncture the tire if they're severe enough. It is the fastest, though, when new. Very lightweight, too. 2. The Michelin PSC is a relatively hard Dot-R tire, that will last a long time but gives up grip to almost all of the other Dot-R tires. Good for DE use. GREAT for endurance races! Very resistant to flat-spotting. 3. The RA-1 is another good Dot-R tire that lasts a long time. More grip than the Michelin PSC, and almost as durable. I've seen guys do 5 or 6 weekends on them. They're obviously not as quick in the last weekend, but they're enough to have fun on in DE's. You can get them from Bob Vilven at Vilven Tire Company, Inc. [phone removed]. 4. The only Kumho track tire I've ever liked in the Victoracer. All the later generations, I've felt, sucked. The Victoracer is durable and quick, maybe only a second off the Hoosier RS tire, but it stays consistent throughout a session or race, unlike the Hoosier. Admittedly, I only have experience on the Kumhos in BMW's, not Porsches, so YMMV, if they're even available in the right sizes. 5. I have not tried the new Dunlop Dot-R tire yet. I've heard varying opinions but someone I respect has said they're similar to the RA-1 but not as durable. 6. No experience on the Pirelli nor has anyone I know related an experiences on them.

p zero corsas

Thanks for the replies, guys. Mooty, I went all the way down to 32 HOT, and all the way up to 51 HOT! I don't know what else to do with those pressures. At 32, I was running on the letters of the sidewall. Finally got off the letters at 51, but by then I had worn down about a quarter inch of the shoulder all the way around almost to the cords on the left rear. Fronts were OK at 38 HOT.Thats when I made the midnight run for the Dunlops. The alignment was just checked to stock specs about a week ago. I really need more negative camber, but the Dunlops and P-Zeros were not this bad at this setting. As an aside, I played tag with a 2005 GT3. I was on the Dunlops by then. He had added roll cage, replaced the seats with Recaros, had 6 pointharness, and mean looking MPSC's. He came up to me slowly, and I let him pass. Decided to go 10/10ths to see if I could keep up. After 2 laps, he let me pass!! In the Black run group!!!! He later came up to me to check out the C4S, then made a comment that his MPSC's were getting greasy midway through the laps. Heh-heh . Made my day. SRL, thanks for the comprehensive summary. Big help there. I'll give Bob Viven a call and check out prices. I can't figue out why the Corsas have to have dedicated left and right side. Are the left side tires thicker on the shoulders due to the expected clockwise run on the track? This dedicated left and right messes up switching/flipping tires for longevity.

Palting - The P 0 Corsa can be moved side to side. They are directional though. Don't confuse them with the P 0 Corsa 'System" which is a more street oriented tread. A great sticky street tire but not best for DE unless it's raining. The Corsa System is similar to the SSR Dunlop i.e., an R compound with a street tread pattern and good water evacuation. I find the CUP stickier than the Dunlop or the Corsa but they are lousy in the wet. Poor water evacuation. The Corsa lasts longer say, 30-35 heat cycles versus about 25 for the Michelin. No matter what, you need to get about 2.5 deg negative camber to avoid premature shoulder wear. OTOH, that much camber will wear the inside edge if you do a lot of street miles. I run the Corsa and use it as both a street and track tire. I heat cycle them to death before the tread wears out. Regards,

Have run MPSC's and P Zero Corsas at TWS DE's. Unfortunately, upgraded to X73 between the sets so am somewhat cautious of comparing/advising. Suffice that both are commendable - with my present bias to the Corsas. The preference largely driven by the Corsa's more communicative approach to the limit. Although how much this is due to the X73, I can only guess... Also the superior wet grip of the Corsa's affords a greater "get home" element... BTW - am running Corsa's on the fronts..and System (N6) on the rears. PM me if you'd like to understand how this arose. Such an arrangement is not optimal for street driving, but find it no problem for track work.

Awesome, so obviously had a great time...you guy's got lucky with the weather too. Palting, what times were you running...is sub-50's possible with a stock setup.

I was just waiting for someone to ask I had just bought a Hot Lap timer. Had to sneak it into the track since NNJR emphasizes it's a non-timed event. I was running 1:49-1:50's on the Dunlop SSR's. Best time was 1:48.33, when I was going 10/10ths with the GT3. Great weather with temps in the 60-70's helped. Back on topic. Looks like it's a coin toss between MPSC's and Corsas.

Tire rack charges different prices for R and L rear p-zero corsa 285/30/18. so, It looks like it's side specific, infact one of my tires is shipped from a different location, so it has to be side specific. jeeva EDIT: My mistake, they are the same price but are being shipped from different locations, and they are listed as R and L as seperate orders ???

Did you see my response in the DE forum, p0 corsa's are on sale at tire rack, so much cheaper than the mpsc's.

palting, aren't you supposed to be tracking your new 987s ;-) your shoulder wear is most likely due to not having enough camber. mpsc doesn't work unless you got at least 2deg of camber, and preferably more. i got 2.5, and the wear is incredibly even. i have ran both ra1 and mpsc extensively. mpsc is a LOT stickier than ra1's for me. both ra1 and mpsc are very very consistent from beginning to end of a 30 min. session. my never gets greasing on me unless i run 60min sessions.

Thanks, jeeva. Saw that. The inability to switch left for right, however, makes me hesitate. By switching, I effectively double the usage. Im thinking the savings on purchasing will be outweighed by the decreased usage mileage. The 987S so far has only 1200 miles, John. I'm a stickler for break-in procedures. Maybe by the end of this month, maybe with TracQuest at Mid-Ohio, I'll be able to see if there is a beast in the heart of that mild mannered Boxster S . I'm leaning towards the MPSC's, but, as you said John, I have to dial in more negative camber for it to be worth it. With the plan for now to make the 987S more the track car, maybe I'll just wait and put the camber changes to the 987S.

Palting, can you post the video of one of your sub 50' laps. Thanks Jeeva

Sorry, jeeva, no video. I had to use the camera mount to mount the Hop Lap timer receiver. The harness bar was too low, so the receiver had to go on the camera mount. Ergo, no vid. Man, I would have loved to have a vid of that GT3 passing, then letting me pass 2 laps later. I do have vids from last years runs. No lap timer, though. I'll check and time the laps on the video and see if I have a sub 1:50 from those and post them.

Sorry, jeeva. The best lap I found from available videos from last year was about 1:50 based on stopwatch timing the video. Here are some pics from the hot lap timer during my last run. The GT3 had already gone home, so I was doing a comfortable 7/10ths driving. Best time at this pace was still 1:49. Here's a sampling of the other times on this run: And, just for kicks, the cool down lap

Plating does'ny matter, it's not like I am looking for a proof , I want to see the lines and try to gauge the momentum through turns as we both drive the same car, so the old video would do, if it's not too much trouble...what sort of time improvement would you credit the r-compounds. Thanks Jeeva

Jeeva - re-reading my own post I realize that I worded it badly. The P 0 Corsa is side specific i.e. there is a left and a right. In the dry you can move them side to side, this means the tires are running backwards, i.e., tread grooves pointed the wrong way. That's OK as long as it doesn't rain. This helps even wear from side to side - since most tracks are clockwise, the left side tires work harder than the rights. Sorry for the confusion my post caused. Rgds,

Bob, thanks for that clarification, and it opens up the possibility of switching sides, which I was'nt aware of, so thanks.

Bob, I still wonder why they make a right and a left. Thicker shoulder for the left? I switch the directional Dunlops when on the track and don't have time to flip them on the rim, so I do run directional tires backwards on occasion. As far as driving lines, here's an old video I posted last year: Mid-Ohio . It's the same line that I used last weekend, just faster. I have a higher resolution of the whole run, but it's a 1.8 gB file . Wish I had the timer to compare the PS2 and SSR times, so all I can say is it felt at least 10 seconds a lap faster. A few pointers for you on the C4S. You can trail brake like any other car to help the turn-in, but get on the gas early, almost as soon as the turn-in starts. Modulate the gas as you approach the apex. This gets the VC of the AWD to transfer power to the front. This will pull the front end around the apex faster, and you can go WOT earlier than most any of the other cars out there. It actually feels like oversteer. And, trust those big red C4S brakes. I have them stock, and they are awesome with the SSR's. Slow in, fast out really works for the C4S. Experiment, and you'll be surprised how much faster your exit speed will be. The guy you're passing will barely have time to give you a passing signal .