dgm8138

Pirelli Dh slicks 265x645x18 235x645x18
-or-
Hoosier R7 245x35x18 275x35x18

and why?

I've worn out 5-6 sets of 200 tw street tires and I'm curious what the next level is like.

This is for a 987.2 base cayman with R springs, -3.0 degrees of camber in the front, and -2.0 degrees camber in the rear.

I don't want to incite a discussion of when to jump into R-comps and which one (not on this list) to jump into.

These are used competition tires that can be had on the cheap. And I'd like to try them because my RE71rs are not going to make it through my last event this year and I don't really want to buy another set of tires to store over the winter.

Bill Lehman

I ran a set of take-off Pirelli slicks on my Cayman S last year. Once they were up to temperature they had a lot of grip. I never felt comfortable to about the third lap. Other good choices are the Hankook Z-214 and , with a little less grip, BFG R1.

dgm8138

Thanks for the feedback, Bill.

What about the tires would you say took 3 laps to feel comfortable with them? Is that unusual for you?

Slakker

You might see which ones are available more consistently to see if that has any impact. It was explained to me that they are very similar but the Pirellis have a little more grip and the R7s have a little more life. But they Pirellis were easier to consistently get slightly used in my sizes so I'm going to try that route.

Frank 993 C4S

I think this really depends on your experience level.

From a learning perspective, the Hoosier R7s would be a more natural progression, especially if you are coming from street tires. You can easily damage Pirelli slicks if you don't get enough heat into them before you put lateral load on them and hit curbs. This usually results in blowouts. For that reason, I would NEVER run somebody else's Pirelli take-offs - but that's probably just me.

Cory M

One thing to consider is the relatively soft springs you are running. Set ups optimized for slicks generally use a much higher spring rate because the sidewalls on slicks are significantly softer than dot tires like the Hoosier. Used tires are always a gamble, so it's impossible to say which ones will last longer for you. Why not buy a set of each and compare your lap times with your existing set up?

mark kibort

R7s will last longer and give you the next step to what you are trying to do with your car. the slicks might only have 2 heat cycles left on them before they equal the R7s and then they will wear faster as well. also the DH tires are much less true to size than the R7s. so you are gettting a much larger tire with the R7 than a comparable DH. in fact, the 265 might be more like a 235 and the 235 might be closer to a 205.
(my experience and measurement was that the 305 was the same size as a 285)

so , that alone woudd push me to the R7s

however, if you have the time and they are cheap, worth the mounting cost to experiment. i still have a full set left that ill be using next season.
might even get a few this next weekend!

Veloce Raptor

Frank nailed it.

dgm8138

This is exactly the experience I wanted to hear. Is there some way to inspect for this sort of damage?

My primary deterrence from the R7s is their size. I'm concerned that there will be clearance issues. Has anyone installed this particular size on a lowered base cayman?

zadar

I am running those on my 987.1 without issues. It will depend on how much you lowered and what wheels/spacers you run.
For example I run NT01 as well and swap spacers between tires.

Frank 993 C4S

No - the damage is internal to the tire and you won't know until it blows.

Pirelli recommends cold pressures not to be below 23 PSI, however at that cold pressure your hot pressures will be 5-6 PSIs too high so the procedure is to start at 23 and then bleed the tires down to the 28/29 hot target range after a couple of laps. Some people don't do this and instead go out at 16/17/18 PSI (as you would do in a race situation) and damage the tires. Pros and advanced drivers know how to get these tires up to temp in a pace lap from very low pressures but most other people don't without damaging them.

AudiOn19s

I agree with R7 here....I mean ultimately I don't but you said to keep that out of this discussion.

IDK where you are located but late in the year like this if you are in a cold climate area you might never get enough heat in the Pirelli's to get them to work period...let alone after 2-3 full warmup laps.

Cory M

Are you really seeing a 10-13 psi pressure delta from cold to hot? That's nearly twice what I'm used to seeing on both slicks and rcomps (using nitrogen).

For the OP: just know used tires are a total crapshoot. Some are great and some are junk. Difficult to tell the difference if you can't inspect in person, and every one says "they only have 4 or 5 heat cycles." I have run my share of used racing tires, from rcomps to slicks. If I didn't have my own mounting and balancing equipment and had to pay a shop to do it for me, I doubt it would be worth it in the long run. Try not to draw too many conclusions from the used rubber.

Frank 993 C4S

Yes - running Nitrogen and is track dependent.

Veloce Raptor

One caution about running full slicks like the DH on cars with stock street suspensions and bushings:

The extra cornering loads at speed will generally cause a lot more body roll, which is counter productive. Also, you will get accelerated wear of suspension elements.

Overall I'd stuck with the R7 or Z214 at most on a street car.