RS 4.0 values - sorry tyre pressures......

[pistolp]

Sorry my mistake there......so used to talking about values it was a freudian slip....

Just took out the 4.0, got back and it's gone up another 10k apparently........lol

Seriously, the pressures. Book says 1.9 on the fronts and 2.3 on the rear. Parr say 2.1 all round for track work and to reinflate for the road.

My question is, is the book value for when they are hot? Assume so? I filled them up to 1.9 and 2.3 respectively this morning, after a bit of a run they were up to 2.3 and 2.6. Should I bleed them down to 1.9 and 2.3?

Thanks in advance.

[Callughan]

They will come down back to original value when cooled. So leave as is.

[pistolp]

Yes sorry I know that. What I was asking is are the recommended pressures hot or cold?

[Callughan]

normally cold

[DiscoColin]

pistolp said:

Yes sorry I know that. What I was asking is are the recommended pressures hot or cold?

They are quoted in the book for cold tyres at an ambient temperature of 20 degrees C.

[R1nur]

Cold.

[R1nur]

I love watching them tick up and the satisfaction both fronts are identical and both rears are identical.

Always amazed at how quickly they go up too. Wish indication it was psi tho!

[BertBert]

Presumably the parr 2.1 will be the hot pressure?

[V8KSN]

R1nur said:

I love watching them tick up and the satisfaction both fronts are identical and both rears are identical.

Always amazed at how quickly they go up too. Wish indication it was psi tho!

You can change the indication from BAR to PSI within the settings menu

[pistolp]

Yes parr is hot

There is a great app called convertbot on the iPhone that can covert all values across all metrics, worth getting

[stefan1]

I took my 4.0 for a run yesterday with some friends and we found that the car benefited (a lot) from lowering pressures when the tyres were hot back down to around 2.0 / 2.2 (hot).

The car's pressures had been set per OEM recommendation to 1.9 / 2.3 cold, and had risen to 2.7 at the rear. This made the car very twitchy. Lowering the pressures transformed the car.

On track, I generally run GT3s at OEM pressures but when the tyres are hot - this is the first GT3 where I've found I need to lower pressures for (progressive) road driving as well.

I do always bring the cold pressures back up to OEM for the next journey to avoid over stressing the sidewalls.

Cheers