GT3 tire pressure

[colonel]

Hello,

What is the Porsche recommended tire pressure for 06-07 GT3? I asked the dealer and they said 36/44. That seems a bit too high. Try to get a reference for MSC tires when used on street. My car is a 05 C2S.

Thanks for the help.

Edited April 20, 2007 by colonel

[paul summers]

Hello,

What is the Porsche recommended tire pressure for 06-07 GT3? I asked the dealer and they said 36/44. That seems a bit too high. Try to get a reference for MSC tires when used on street. My car is a 05 C2S.

Thanks for the help.

In competition as a rule your tyres when hot should equal the recommended road pressures provided by the manufacturer. This applies to 18" and 19" "r" spec tyres such as fitted to the GT3 997.

32 PSI Front and 39 PSI would be an appropriate pressure for regular use when cold and this pressuers should be maintained as a "hot" pressure during competition.

For road use when "wet" using the Michelin Pilot Sport Cups I suggest increasing the PSI to 35 Front and 43 Rear .

[colonel]

Hello,

What is the Porsche recommended tire pressure for 06-07 GT3? I asked the dealer and they said 36/44. That seems a bit too high. Try to get a reference for MSC tires when used on street. My car is a 05 C2S.

Thanks for the help.

In competition as a rule your tyres when hot should equal the recommended road pressures provided by the manufacturer. This applies to 18" and 19" "r" spec tyres such as fitted to the GT3 997.

32 PSI Front and 39 PSI would be an appropriate pressure for regular use when cold and this pressuers should be maintained as a "hot" pressure during competition.

For road use when "wet" using the Michelin Pilot Sport Cups I suggest increasing the PSI to 35 Front and 43 Rear .

Thanks. I think I will stick with the C2S recommended pressure for road use.

[Bluehinder]

Hello,

What is the Porsche recommended tire pressure for 06-07 GT3? I asked the dealer and they said 36/44. That seems a bit too high. Try to get a reference for MSC tires when used on street. My car is a 05 C2S.

Thanks for the help.

29/30 factory for 07 GT3.

[drqiman]

Hello,

What is the Porsche recommended tire pressure for 06-07 GT3? I asked the dealer and they said 36/44. That seems a bit too high. Try to get a reference for MSC tires when used on street. My car is a 05 C2S.

Thanks for the help.

29/30 factory for 07 GT3.

The sticker on the driver's door of my April production 997 GT3 says F 29 psi R 33psi. The cars seems to handle fine and the tire wear with 2200mi is even with the rears showing more wear in the inside.

[stuski65]

Hello,

What is the Porsche recommended tire pressure for 06-07 GT3? I asked the dealer and they said 36/44. That seems a bit too high. Try to get a reference for MSC tires when used on street. My car is a 05 C2S.

Thanks for the help.

29/30 factory for 07 GT3.

The sticker on the driver's door of my April production 997 GT3 says F 29 psi R 33psi. The cars seems to handle fine and the tire wear with 2200mi is even with the rears showing more wear in the inside.

Notice that sticker, I did, I wouldn't be surprised if Porsche has to replace them, send us all new ones,

It says, "back seat capacity" 2.

I wonder where that sticker came from when the GT3 owners manual has a

different tire pressure than the door jam.

I think the owners manual tire press. is correct.

The door jam sticker appears to be from another model with back seats.

DO NOT put more pressure into the car than owners manual says for normal

street driving, the active suspension was designed for specific tire pressure.

[PAULSPEED]

Hi,

I would check it with a tempeature gage you can get from

Radio Shack for $75.00. If the temperture

in the midle is colder then the outsides, your tire

is low on pressure.

Paul

[sotorios]

Hello,

What is the Porsche recommended tire pressure for 06-07 GT3? I asked the dealer and they said 36/44. That seems a bit too high. Try to get a reference for MSC tires when used on street. My car is a 05 C2S.

Thanks for the help.

I have an 07' GT3 with MICH Sport Cups and the recommended cold is 29psi front 31psi rear!

[berty987]

I would have thought it important to increase the tyre pressures for track work , so long as the maximum tyre pressure isnt exceeded. Having recently done an airfield driver training day in my 987 , i found the 34 psi front pressure on 235/35/19 michelins far too low resulting in excessive scrubbing of the outer edge of the tyre and a strong tendency to understeer. Putting the pressures up gave a significant improvement in handling and reduction in edge scrub when run at closer to 45 psi all round. Note the instruction was with PSM off which highlights the cars true chassis characteristics.

[nfesas]

I would have thought it important to increase the tyre pressures for track work , so long as the maximum tyre pressure isnt exceeded. Having recently done an airfield driver training day in my 987 , i found the 34 psi front pressure on 235/35/19 michelins far too low resulting in excessive scrubbing of the outer edge of the tyre and a strong tendency to understeer. Putting the pressures up gave a significant improvement in handling and reduction in edge scrub when run at closer to 45 psi all round. Note the instruction was with PSM off which highlights the cars true chassis characteristics.

Don't know all the details, so forgive me if I'm off. It seems to me that the tire pressures are a function of ambient air temperature (and by extension, road/track surface temperature), humidity (?) and how much work the tire is performing. I would agree that on a cold surface/day you might in fact start with a higher pressure. I live in Texas where daytime highs can easily creep into the high 90s / low 100s. I've been experiencing tire pressure increases of as much as 10lbs in the rear and about 7 or 8 in the front. The shoulder wear indicators (little arrows on the shoulder of my MSCs) seem to indicate appropriate wear when I have about 44lbs hot in the rear and about 37 hot in the fronts. These numbers work on days with temps in the mid 90s and humidity up around 80% or so. Also, these are for Texas World Speedway which is a 2.9 mile, 15 turn, high speed track (wide track, plenty of run-off, etc). I use a 2006 Boxster S, so I understand that your application will be different. I think the bottom line is that the tire pressure will be dictated by a number of factors that will change with track and weather conditions. For track use, it's probably a good idea to keep a log of the various variables just to get a sense for what works best for your driving style and car.

Regards,

Nestor

[nfesas]

Found this link to a Michelin "Care and Feeding" PDF for the sport cups. Seems to have some useful info.

Nestor

http://www.tirerack.com/tires/tiretech/tec...e.jsp?techid=62

Edited September 12, 2007 by nfesas

[berty987]

Good links. Seems to make sense. I assume that a normal road tyre differs from the cup tyre in sidewall strength. My experience of yokohama A008 tyres is they are much stiffer in sidewall than most tyres i've used , and these also have a continous block pattern on the edge. I guess it comes down to tyre design and expected use.

[Flash1034]

I suspect I was running way too much air last weekend at Willow. It was 95 degrees F ambient and I was running the recommended street pressures. The tires became pretty slippery on the track. I was catching the car all day. After reading the Michelin PDF, It appears I was running at least 5-7 psi (cold) too high for the prevailing track and conditions.

Flash

[997GTDREI]

I suspect I was running way too much air last weekend at Willow. It was 95 degrees F ambient and I was running the recommended street pressures. The tires became pretty slippery on the track. I was catching the car all day. After reading the Michelin PDF, It appears I was running at least 5-7 psi (cold) too high for the prevailing track and conditions.

Flash

What do people recommend for hard street use on an 08 GT3 with regular Pilot Sports (not cups). I'm thinking around 35 fr, 40 rear. Any recommendations from GT3 owners?

[irysfan]

For street driving, go with the manufacturer's recommendation. If needed, -1-2 psi cold to see if you go any faster. -2-4 psi cold if you slide around a lot. +1-2 psi cold if you want better response. You want to stay within the recommended hot pressure range. Either way, it won't help too much on the street without driving excessively fast n the GT3 IMO.

Adjusting tire pressure is a mean, among others, to the goal of getting tires to operate at the temperature range that maximizes traction, with consistent temperature across the tire. The general rule is to get the tires to reach the temperature of the side of the car that work the hardest, provided that side is not overheated.

Tire pressure can alter cornering balance also, but it's generally better to adjust suspension / alignments for that.