GT3 Tyre pressures HELP!
GT3 Tyre pressures HELP!
Author
Discussion

bridey0

Original Poster:

2,961 posts

216 months

Saturday 4th February 2012
quotequote all
Hi, i have Michelin pilot sports (not cups) and think im running too higher pressures. The manual states 29 and 33 psi for summer tyres and 33 an 39 for winter tyres. The label on the door just states the pressures for summer tyres which wud be the original Cup sports i guess. HELP!

majordad

3,631 posts

228 months

Saturday 4th February 2012
quotequote all
I ve run my 7GT3 from new on the factory door pressures and always had even wear, well very slight inner wear at the rear. I recommend the door settings and measure wear every 1000 miles and adjust.


bridey0

Original Poster:

2,961 posts

216 months

Saturday 4th February 2012
quotequote all
majordad said:
I ve run my 7GT3 from new on the factory door pressures and always had even wear, well very slight inner wear at the rear. I recommend the door settings and measure wear every 1000 miles and adjust.
Ok great but what tyres do u have ???

NIgt3

627 posts

205 months

Saturday 4th February 2012
quotequote all
I run my cups at 27 front and 29 rear and also have run Michelin sports at the same, was told to run this pressure by manthey motors, but this was for the track but I,ve kept it the same for the road and no problems feels good.

bridey0

Original Poster:

2,961 posts

216 months

Saturday 4th February 2012
quotequote all
NIgt3 said:
I run my cups at 27 front and 29 rear and also have run Michelin sports at the same, was told to run this pressure by manthey motors, but this was for the track but I,ve kept it the same for the road and no problems feels good.
Ok, my tires seem too hard on the winter pressures but thought I'd check also it's how the OPC delivered the car

bridey0

Original Poster:

2,961 posts

216 months

Sunday 5th February 2012
quotequote all
So just to be clear we're saying same pressures for track and road if I set them on 29 and 33 as per setting for summer tyres?

ttdan

1,113 posts

224 months

Sunday 5th February 2012
quotequote all
yes, on track they would rise dramatically with the extra heat you'd generate so you would manage the pressures back down to the 29/33 ish, some go lower than that.

But on the road start at 29/33 cold and leave it there.

bridey0

Original Poster:

2,961 posts

216 months

Sunday 5th February 2012
quotequote all
ttdan said:
yes, on track they would rise dramatically with the extra heat you'd generate so you would manage the pressures back down to the 29/33 ish, some go lower than that.

But on the road start at 29/33 cold and leave it there.
Sorry but above you're saying the same for track and road? What pressure for road? What pressure for track??

ttdan

1,113 posts

224 months

Sunday 5th February 2012
quotequote all
bridey0 said:
ttdan said:
yes, on track they would rise dramatically with the extra heat you'd generate so you would manage the pressures back down to the 29/33 ish, some go lower than that.

But on the road start at 29/33 cold and leave it there.
Sorry but above you're saying the same for track and road? What pressure for road? What pressure for track??
Yes, the same for track and road. The difference is on track the pressures will rise dramatically so you would need to let air out and keep them close to the road pressures.

so, on the track 29/33 when HOT, on the road 29/33 when COLD, does that make sense?

bobsan

495 posts

250 months

Sunday 5th February 2012
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your road pressure will be as per manual, for track work, after just a couple of laps come in and measure, they should be at least 3-4 psi increase, at this point drop that 3-4 psi and go out again for 15 mins, come in and measure.

what your looking for is roughly max 5psi above stated pressure - track tyre's are very much how the individual drive's, how hard you corner, how hard you brake, on a warm day if left unattended rear pressure will creep right up to late forties early fifties even, vehicle will feel stish and you'll start to wear out the tyre middle.

one thing to remember when heading home from track is to replace all the air you've dropped during the day.

bridey0

Original Poster:

2,961 posts

216 months

Sunday 5th February 2012
quotequote all
ttdan said:
Yes, the same for track and road. The difference is on track the pressures will rise dramatically so you would need to let air out and keep them close to the road pressures.


so, on the track 29/33 when HOT, on the road 29/33 when COLD, does that make sense?
Yes tks m8. I need to deflate then as currently they on 34 front and 39 rear!!!

lewea

189 posts

209 months

Monday 6th February 2012
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Bridey,

Just don't forget to re-inflate your tyres after a track outing.

I did a day at Snetterton in my GT3.2 one summer time and by the time I had finished the day, driven almost back to London and filled up with fuel, the TPC warnings came on, took me a couple of days to get the pressures back to the factory settings as set in the inside of the doors.

Cheers
Lewy

bridey0

Original Poster:

2,961 posts

216 months

Monday 6th February 2012
quotequote all
After reading a number of other threads ive kinda deceded ill leave on 33 and 38 and delflate by 5psi during track days. There is some suggestion on another Thread i read that 29 and 33 causes inside tyre wear so ill see what happens!

Gibbo205

3,572 posts

238 months

Monday 6th February 2012
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Hi there

On a Carrera the cold temps are 33/39 on Summer tyres, which PS2's were a regular fitment.

The GT3 has lower pressures for Summer tyres as their summer tyres with either Michelin CUPs or Corsas which have a far far stiffer sidewall than a regular Summer tyre such as a PS2.

As such for the road on a GT3 which weighs a bit less than a Carrera I'd go with something like 31/37 cold on the road and for track days drop them down to around 27/29 as hot they will be around 36/38.

Running too low a pressure on the road with normal tyres like PS2's could potentially cause wheel damage too from pot holes etc, due to softer tyre wall.

bridey0

Original Poster:

2,961 posts

216 months

Monday 6th February 2012
quotequote all
Gibbo205 said:
Hi there

On a Carrera the cold temps are 33/39 on Summer tyres, which PS2's were a regular fitment.

The GT3 has lower pressures for Summer tyres as their summer tyres with either Michelin CUPs or Corsas which have a far far stiffer sidewall than a regular Summer tyre such as a PS2.

As such for the road on a GT3 which weighs a bit less than a Carrera I'd go with something like 31/37 cold on the road and for track days drop them down to around 27/29 as hot they will be around 36/38.

Running too low a pressure on the road with normal tyres like PS2's could potentially cause wheel damage too from pot holes etc, due to softer tyre wall.
im on michelin pilot sports..What pressures do u suggest for these?

Gibbo205

3,572 posts

238 months

Monday 6th February 2012
quotequote all
bridey0 said:
im on michelin pilot sports..What pressures do u suggest for these?
I'm no expert and can't recommend for sure.

But a GT3's stock summer tyres are more track orientated in the form of CUPs or Corsas from the factory which have far stiffer sidewalls compared to a regular Summer tyre as the PS2.

A Carerra S runs 33/39 cold on Summer tyres, PS2's for examples.

If your running a GT3 on these tyres, which is a lighter car, I'd try 31/37 cold and see how it effects the cars handling and maybe do some experiementing until you find what is best for you. smile

bridey0

Original Poster:

2,961 posts

216 months

Monday 6th February 2012
quotequote all
Gibbo205 said:
I'm no expert and can't recommend for sure.

But a GT3's stock summer tyres are more track orientated in the form of CUPs or Corsas from the factory which have far stiffer sidewalls compared to a regular Summer tyre as the PS2.

A Carerra S runs 33/39 cold on Summer tyres, PS2's for examples.

If your running a GT3 on these tyres, which is a lighter car, I'd try 31/37 cold and see how it effects the cars handling and maybe do some experiementing until you find what is best for you. smile
Ok very kind tks