My thoughts on tires for the track

[DJF1]

Sometimes there is plenty of confusion regarding track days or DE's for the US folks and what tires to use.
Since I do not have any other experience with another brand but Porsche I will offer my experiences in regards to this matter in this forum.

First and foremost , Porsche owners should take their cars to the track, this is the only place that they will be able to enjoy properly and safely what Porsche is all about.

So there are three really choices to use:
1. Street tires
2. R- tires
3. Slicks

I will not bother with slicks as they are expensive, last little and they do not offer anything really to the track day enthousiast. If you are racing its a different story, but this is not what I want to talk about.

So it would be wise for the first time track day driver or even somewhat experienced driver to stick to street tires. Why you would ask. It is simple. For most enthousiasts they want to be able to learn how to drive their car on the limit. By using more advanced R tires you move to a higher limit therefore you get lower value on experience with street tires which you would use every day. Furthermore the street tires are more progressive on the limit which is very important to feel the slide so to speak as it is about to happen, therefore be able to correct and more importantly learn to correct over or under steeer situations better and easier.
So the begging question is when do you actually move if ever on R-tires? The answer is simple. When you put enough heat on your street tires and start chewing them up literally on the track then you are ready for R tires.

So the next question is, what are R tires? Most manufacturers will tell you that they are "street legal" DOT approved racing tires. While this holds water for some, for others means that in reality they are street tires with special compounds and usually stiffer sidewalls and are designed to optimize performance on the track with some actually run on normal street duty.
Indeed R-tires are great for the track, they literally propel you to a different level of performance but the draw backs are that they will not give you an audible warning so to speak when they are about their limit and they will "snap" faster and at a higher speed of course when they breach their limit. What that means to you? Basically you have to be more trained to catch ugly situations as you have more chances of spinning out on R-tires than street. The rewards though for the experienced driver are that your performance, cornering loads are unreal sometimes.
Another draw back usually associated with R- tires is tirewear. Some will only last a weekend, some several weekends which becomes expensive at the end of the day. Furthermore most R tires cannot really be driven in heavy rain as their grooving is shallow or even non existent on some like the Hoosier R04 or 03.
I mentioned before that some R tires can actually be used for street duty ( again rain is a consideration) but the important thing to consider is that the R tires to be used as a street tire it must be radial steel belted like the Michelin Pilot Sport Cup tire in order to be able to withstand the normal road punishment of everyday driving.

So the next question would be which tire?
This is more complicated ofcourse as different tastes demand different tires. From my experience I will provide my impression on some tires I have personally run. Please bear in mind that since I'm in the North American market I only have access to some tires not to all tires.

1. Street tires. Something important to think here is that the newer tires are NOT necessarily better that older ones! You say what??? Isn't supposed to be the opossite? Well... you have to think that tire manufactures they address a wide variety of people when they produce new tires. Often the biggest complaints they try to solve are tirewear, better "ride" and low noise. These 3 considerations are NOT considerations for the ultimate performance tire!!! So the newer tires will use a bit of softer sidewalls, a bit harder compounds, deeper grooving etc which are not really providing ultimate traction! So while the manufacturers provide the same grip and in some instances a bit better grip, I have found that newer tires like the Bridgestone S03 are vague and squirmy until they shave a bit of their tread. On the street however they are great with great rain performance. Here however we are talking about tires for the track and the S03 is not one of them in my book.
My favorite tires for the track is the older technology Pirelli P-Zero assymetrico. These were designed for the F-40 and still today they are a fantastic dry track tire. They warm up nicely and provide great steering feedback and traction on the dry track while they are progressive on the limit.
Another great tire is the Bridgestone S02-A tire , the Michellin Pilot Sport RIB and from what I hear the new Michellin PS2 which comes standard on the GT3

2. R-tires. My favorite all around R tire is the Michellin Pilot Sport Cup. It lasts long, it has great traction and it very progressive letting go at the limit. Plus it can be used on the street if one so wishes, I usually ride on them to the track. Only drawback is that it takes about a lap or so to heat up , but once it reached operating temperature its a really nice tire.
For ultimate lap times, the Hoosier R DOT tire is the ultimate track day tire. The older model which I have tried has incredible stick but you are looking at one or 2 weekends of max use and for use they are not streetable.
A lot of people really like the Kumho Victoracer, it lasts a few weekends, more than the Hoosier but less than the MPSC , it does not stick like the obove 2 tires but the major advantage is that it is very cheap.
The Pirelli PZero Corsa is another good tire, with the same characteristics as the Michellin, but by all accounts it is slower than the Michellin so there is really no reason to look at this tire as it is equally expensive to the Michellin so no advantage there unless you can find specific sizes that are not available with the Michelin.
The new Kumho V710 looks like the ultimate track day tire with the same characteristics as the Hoosier, but as it is cheap it could have the advantage. Problem is though that recently there was a recall on them for tread falling apart, if they fix the problem it may be worth looking at.
Another good tire is the Toyo RA-1 which by many accounts it looks to be the rain tire of R tires. Good dry characteristics with good grooving for the rain make it a very versatile tire for the track.
Finally a new player in the US market is the Dunlop SP sport race which is an R tire with what it looks to be great grooving for the rain, but I have not tried it yet, nor any of my friends so I cannot say. If someone has drove on this tire please post your impressions.

A final note on tuning R tires on the track. First of all it would be very helpfull to get a Pyrometer, the prob type which is more accurate. With a Pyro you can see the operating temp spread accross 3 points on the tire and see if you are running the correct tire pressures. R tires usually have a sweet spot for example, the MPSC wants over 160F temps with pressure between 32-25 PSI HOT. So it is extremely important to find what the manufacturer suggest operating temp and pressure HOT and then work from there.