IvanBurns

I've only seen this mentioned once as a rumor in OrthoJoe's Track Journal but now it's official as far as I'm concerned - Hoosier will be offering 20" A7 and R7 tires next year.

I say this is official because I got the word directly in response to an email that I sent to a Hoosier product manager. Complete size designations are not yet finalized but he expects that the 20" R7 will be offered in 245, 265, 295, 315, and 345 sizes. He said that he would be able to give me an update next spring.

This is great news to me because I use and like Hoosiers on my GTS but have not been eager to drop to 19" wheels on my GT3. I prefer 20" wheels because I trust the Porsche engineers' philosophy that "bigger is better" when it comes to wheel sizes. They clearly feel that the larger contact patch overcomes the weight penalty.

I know that there are some number of GT3 owners that are running Hoosiers on 19" wheels. Assuming that most of you still have your factory 20" wheels, I would be interested in hearing of your experience if you decide to compare the Hoosiers on both 19" and 20" wheels.

SamFromTX

I heard that as well. Apparently the problem was not demand but rather the machine that makes 20" tires. Great news for GT3 owners but not so much for new RS ones. I wonder if changing the RS's rear wheel to 20 would work but not sure if they will have a same size tire with a different rolling diameter, ugh.

Sarum87

Dumb question but can you drive to the track with Hossiers? I'd like to run them but not excited about buying a truck and trailer.

Santi

How far are you from track? I have driven A6's to and from the local Autox 20 minutes away. You will be flinging rocks and debris everywhere.

Mussl Kar

People do it for short distances and the weather must be dry. They are rated DOT. Some I know drive 20 miles and inflate to max. I did 80 miles once, inflated to 45 pounds and the car was very "nervous" on the highway.
Get a tire trailer setup for your car.
An A7 or R7 can hydroplane on a puddle of mouse ****.

SamFromTX

If you frequent one track only, most venues will have a shop that would store them for you for a nominal monthly fee. If you go to multiple tracks or track infrequently, you can drive but it really has to be bone dry and a short distance as they are not meant for rain and do wear rather fast.

bigkraig

Guest89

Just curious - why the need to inflate Hoosiers to high pressures for street driving?

Alan C.

I drove my RSA from Cincinnati to Road Atlanta on Hoosiers once. That was a long tome ago. Wouldn't do it again.

GrantG

Those tire sizes should work for GT4 also. I think with many shared components among GT3, GT4, and RS it will make offering special parts more attractive to the makers of those parts (much larger market than if each used unique parts). Unfortunately, the 21" wheels on the RS are only shared with the 918, so that could take longer.

Keith Verges - Dallas

If 20" was so great, the Cup car woul use it. I think it's bling and a way to keep sticky tires out of the warranty equation

Mussl Kar

My thinking was prevent any heat from getting into the tire and causing a heat cycle. It was July and hot as hell that day. Other reason was my car had street alignment then and I wanted to stay off the edges because that is where I would cord them.
Hoosier A7/R7 work really well on wet tarmac buy only to a degree. I ran my A7s wet and dry yesterday. 65 seconds wet and 69 dry. By "wet" I am talking about color change like a slight mist would give you. If you can see the slightest reflection of the sky you will hydroplane like on ice.

Good to hear about the 20s as I was wondering what to do when my GT4 arrives next month.

Mass_K

PV=nRT

higher tire pressures mean that the tires will heat up faster and that they will reach a higher temperature...

FRP||

???

Higher tire pressure reduces tire temperature by minimizing flex and deformation.

alpine-al

^^^ Correct.

And the tire expands as the pressure is increased so the volume isn't constant.

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