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Discussion Starter #41 (Edited)
Same set up as mine was. 36 front, 34 rear.

The calculation in the first post is fine.

Except for the bit about adding pressure for driver weight. That was me being an idiot and should be ignored.

THUS:

The baseline method from Oscar Pereda of BF Goodrich. He suggests this as a good starting point if you have abolutely no guide as to what pressure to use in your tyres. This starting point should be regarded for road use only.

(Vehicle Weight in pounds imperial/100) + 2 psi at heavier end + 2 psi all around if suspension and alignment are stock.

Example:

Stock 911, 3,000 lb.
(3000/100) = 30 psi
Add 2 psi all around = 32 psi
Add 2 psi to heavy end = 34 psi at rear

With modified suspension, the result would be 30 psi front, 32 psi rear.

SO:

Stock R33 GTR = 1530kg = 3366lb.

3366/100 = 33.66
Non standard suspension, so only adding 2psi to heavy end.
36 psi front, 34 psi rear.
 

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Same set up as mine was. 36 front, 34 rear.

Stock R33 GTR = 1530kg = 3366lb.

3366/100 = 33.66
Non standard suspension, so only adding 2psi to heavy end.
36 psi front, 34 psi rear.
Really?

Anyone running 19x9.5 with 265x30x19's agree with this?

Cold to warm I made all mine 27psi this morning and thought that looked and felt good...........i've never gone anywhere near 36!!

If the air expands when hot you could be at 40 psi in no time???:nervous:
 

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The baseline method from Oscar Pereda of BF Goodrich. He suggests this as a good starting point if you have abolutely no guide as to what pressure to use in your tyres. This starting point should be regarded for road use only.
Makes sense to me, hes not saying this is it ... he's sayiong this is a good starting point, which it is.
I run my Dunlop Formula R 265 40 17's at 26 lb HOT on the track ...
About 32/34 on the road
 

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IIRC we are typically circuit racing our R32s at about 28psi hot, 315x30x18s all round, but we check this periodically with a pyro to make sure the pressures are correct.
 

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ask 100 people what pressures you should run, and you'll get 100 different answers
And within that 100, you'll get a handful of people who will swear everyone else is completely wrong, as you will on any forum...

It's the same when it comes to:-

Tyre brand and model (gotta love advocates of buying on price)
Tyre width/profile
Petrol brand/octane
Oil choice and change interval
Brake pads
Which tuner is best (and answers the phone)


But that's what keeps forum's alive... :bowdown1:
 

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Different tyres work best at different pressures too! Sidewall construction, tread block design and compound etc. So you can't compare some Pirelli to a Dunlop and expect them to both perform at their best at the exact same psi.
 
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