Silver State Classic...Tire Pressure??
 

I am planning to run in the Silver State Classic the 20th of this month. I have a heavily modified 2nd Gen presently weighing around 2300 lbs. (still looking to trim weight). I have 15 x 10 inch rims shod w/ 275/35/R15 Hoosier R6 racing tires. They are DOT approved as is required by the sanctioning organization.

The competition is an open-road race over a 90 mile distance. There are very few turns to navigate, except for a tight section known as "the Narrows" involving a series of 6 turns in succession that has to be managed roughly 13 miles from the end. [Production cars are handling these in excess of 100 mph, so again I do not see a serious problem for the car I have]

Being a first timer to the event, I am limited to the Touring Class with target speed (average) of 110 mph, and tech speed (the speed you cannot exceed at any point on the course) of 124. The car is fully capable of a much higher class, but the rules are the rules.

My main concern is the starting (cold) tire pressure, knowing that heat will elevate the tire pressure through the course of the run. I plan to speak to the head tire technician before the event, but I was wondering if anyone here has had experience with race tires on extended high speed runs.

I cannot comment on your tire pressures but I would like a full report after the race.

This is my dream to race the Silver State Classic and intend to do so someday. My car needs to be up to snuff to do so and will take until later this year I suspect.

BTW, do you race in Phoenix area? I race at Firebird with my FC.

Your best bet is to call Hoosier directly and tell them what you have and what you're doing. They know the tires better than anybody here.

Roger that. I am anxious to see just how much stress this is for the car.

I plan to start attending HPDE through NASA this fall--or as soon as I have money after this event. Getting the car in true competition form has been more taxing financially than I thought. I honestly felt I had this buggy pretty close two months ago. I am still working on it feverishly and its starting to look like I'll be cutting it close.

I'll be looking for another 2nd Gen at the track.

Getgone = JD to Rescue

Someone else mentioned that. That is probably what I will be doing.


Thx,

JD/Getgone

I was planning on doing some NASA HPDE myself. Currently with Proautosports and so drive Firebird.

Make sure and say hi to a white FC with the V8 in it...you can't miss me.

Ben

I agree with calling Hoosier, but an awful lot of this is going to depend on what you have *in* the tire. Air straight out of a compressor? through a dryer? nitrogen? A lot of the pressure increase you see is actually from water vapor.

Normally I'd ask what you start at cold and what you end up at come the end of a 20-30 minute track session... if you know that you can probably take a guess at where your hot pressure will land and set cold pressure based on the rise you see.

My tip (feel free to take it or leave it) is to not run the hoosiers. The couple of reasons that I can come up with:

They will pick up anything on the road and are very prone to punctures.
The engine will rev quite a bit higher with the 15" and 35 profile tires.
The steering responce is very quick with the Hoosiers and can cause you problems at those sustained speeds.
Tramlining (the few times I have driven to auto Xs on my A6s the car can jump a half lane in an instant).

I would suggest just getting some good street tires to run the event. Not really the answer to your question but just some cautious thoughts since this is your first try at it.

Have fun. My dad is in NM and has been talking about doing the event in his Vette. I would love to come down and try it.

Probably some good advice there. I wrestled with those questions and, if I had a decent set of stock rims, I would have probably went that way. The stock rims, however, are only good enough to use as rollers around the garage. I have also searched for anything in my size rim with more of a typical street tread and there is nothing else. Hoosier says they will run the course as does the head tire tech, so I am hoping they are right and I do not find any 'unfriendly' objects during the run.

I'll also be attentive to the steering response.

Check the rules carefully. At least several years ago, Hoosiers were banned because of some of the characteristics mentioned. Also, tires had to be new.

Pay close attention to what Finky tells you. He has real experience, and is probably the top driver in a many county radius. Based on what he is telling you, I would strongly advise you to find a set of loaner wheels/tires for this event. I'm sure there is an RX7 owner in your area that would be happy to help you out. :)



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I meet the rules and the tires are brand new. Problem I have is whether this makes any sense with such a thin layer of rubber to run such a distance. And then what tire pressure to start at to allow for the expected expansion.

Have great fun in the event. We have a very simlar event out of Fort Stockton in West Texas only move curves in mountainious roads and 60 miles out and then back.

As to tires, I left my Hoosiers behind, (thin walls) and put on some Michelin Pilot Sport Cups to be safe. 90 or 120 miles in heat in triple digits is asking a lot from a tire.