[David713]

I'm currently running Michelin Pilot Sport 4S in stock 235/35-20 and 265/35-20 sizes and don't see any track tires in those sizes.

Moving to 245 front and 265 rear gets me to Pilot Sport Cup 2 but I wonder if the 265's are really made for front tires and what affect would that have on rear end stability?

I know the real answer is to buy 19" wheels so anyone have a lead on reasonably priced 19" wheels for the track?

 

[olegd]

Just run your Michelins on track. Unless you are a very advanced driver, they'll perform fine. To make them (or any other tire) last longer on track, add camber (at least -2.5 degrees) and monitor tire pressure to ensure optimal traction.

 

[David713]

I've been running the 4S Michelins at about 37-39°F hot which is about 28-29 cold. They stick pretty well but I'd like to have a little more traction without going full track tire.

 

[James III]

Why aren't you going wider in the rear too?

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[David713]

There's no 275/35-20" Cup 2 tire. I may buy 19" wheels so I can run 245/35-19 and 275/35-19 Cup 2 tires.

 

[bigmoguls]

I found a used set of 19" 987 wheels for $600. I put 245/35 and 275/35 on them, that work great and there are several tire choices in those sizes.

 

[dcharnet]

Moving from a " summer ultra-high performance" tire of any kind to a DOT race tire is a BIG step up to faster laps, if that is what you (like most drivers) seek. One can debate when to make that transition.

 

[donR]

There is a 235/35/20 and 265/35/20 in the new Cup 2 Connect, like a Cup 2.5

My pick would be to go with the 245/35/20 front and the 285/30/20 rear also available in Cup 2 Connect.

 

[David713]

That’s great news. I didn’t even look on the Michelin site since I figured tirerack would have all available tires. I guess you have to buy from a local Michelin dealer.

 

[dcharnet]

What is the width of your wheels?

 

[David713]

My 20" wheels are 8 and 9.5. I still have plenty of tread on my 4S tires so I'll run them this weekend. If I do decide to go with the Cup 2 tires, I'll probably just buy a set of 19" wheels with the 245/35 and 275/35 tires on them. The 19" Apex wheels in 9 and 10.5 are at the top of my list so far but I'm open to other suggestions.

 

[dcharnet]

Bigger my not be better, it may be worse.

Determine the actual tread width of the tire from MFG specs. The goal should be to have tread width as close as possible to wheel width to minimize flex and lateral/ circular movement under track-level cornering and braking loads, all of which can slow and destabilIze in a too-wide tire.

And, a bigger tire has more unsprung weight and aero drag, the latter an exponentially increasing negative factor above 100 mph. A bigger tire costs more. You lose, incrementally, in multiple ways if you do not carefully match tire and wheel size.

Read MotoIQ, one of a small number of reliable sources for info on this commonly misunderstood topic. Do not rely on data/ fitment specs from vendors who are not experience race specialists.

 

[Kernel Klink]

As a curiosity, has anyone attempted to fit the rear 9.5’s up front, then using a stock Carrera S 11 in the rear? Our factory wheels are fairly light, and sticking with oem would be ideal.


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[dcharnet]

I think of tires, wheels, shocks, springs and suspension design as an integrated system. Change one piece and you may upset the whole. I have read this about X73 in a 981, which is a high-water mark of brilliantly engineered synergizing components that may be diminished if you depart from a tire base of 235/265 and make no other changes. It is easy to spend money and move backward.

 

[Kernel Klink]

Even if the same bias is retained?


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[dcharnet]

I don't know. My sense is that it is more complicated than that, and personally I would get more reliable info before I mess around. But that is my inclination. In another life I raced WTW and used a race prep shop run by a former GM suspension engineer who was rigorous and dismissive of "just messing around." I absorded his approach.

 

[David713]

I had a good DE weekend running on the stock size 4S tires. I noticed quite a few fast drivers running them so I probably need to worry less about tires right now and just get better at driving the car.

I do have a lot of track experience but it's in karts and the Cayman feels like a truck compared to that. The Cayman is so well balanced though, that it makes getting up to speed really fun if not relatively easy.

 

[snakebitten]

I noticed quite a few fast drivers running them so I probably need to worry less about tires right now and just get better at driving the car.

This

Brief version of a longer story.....

I found myself in the passenger seat of a bone stock Miata that was piloted by a current MX-5 World Cup driver for Team Slipstream. (I did NOT know who he was at the time. But it all made sense later)

The next 10 minutes taught me a lesson that for whatever reason I hadn't yet REALLY understood in my 60 years of having fun with 2/4 wheel toys.

Lesson: I can upgrade the tires, wheels, brakes, coilovers,........ But I still can't drive the car as fast and smooth and balanced as someone who has learned how to drive.

I'm not saying that I won't buy better than oem tire or components, but I have been forever humbled by those 10 minutes and personally experienced what a true driver can do. It was like he was dancing with the car.

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[David713]

Maybe I spoke too soon. Both front tires were loosing outside treads. I lowered pressures as the day heated to keep hot pressures about 37-38. Definitely need more camber. They have 3 track weekends on them with each weekend’s laps much faster than the last.

 

[ledbette]

If you haven't had an alignment to max out the front camber, you definitely need to do that. However, camber alone won't fix this problem as you've literally melted the tread across the entire surface of the tire and you're chunking everywhere, not just on the outsides.

I've seen several people destroy nearly new sets of PZeroes and Michelin PS4's on the track once they get to a high intermediate level of HPDE. Once you're at this level, you probably need to look toward a more track-focused tire option. Many street tires just don't handle the heat well, and cars with 20" rims seem much more susceptible to tire damage due to overheating. (The case's I've seen have been almost exclusively 20" rims).

A few suggestions:

I'd recommend getting some 18" or 19" rims and going with a more track-friendly tire like a Nitto NT-01, Bridgestone RE-71R's eventual replacement, Continental Extreme Contact Force, Advan A052, Hankook RS4's, etc. My personal preference is the Nitto's on 18" rims, but everyone has their own opinion and there is a lot of discussion on the forum.

I went the same way as @bigmoguls and got some 987.1 18" rims for $600 off eBay and I swap out my wheels and brake pads when I go to the track.

If you're eating tires like this, you're going to start eating brake pads as well. There is a huge performance and longevity jump going to dedicated track pads, but you really need to swap them between events as they squeal like crazy on the street.

If you're going to be DE'ing a lot, get studs from Tarett for the front calipers to avoid stripping the uprights from frequent pad changes.

You can see a number of articles on track pads and Tarett studs on previous posts in the forum.