Correct Air Pressure For Non Standard Wheel/tyre Setup?

[WhatsHisName 0]

My brother has non standard alloys & tyre size on his VR6.

 

17" Porsche alloys with stretched 215/40 R17 tyres on them.

 

Looking at the fuel cap it says this:

 

 

Just wondering what the correct air pressure may be on this?

 

His rear tyre had in 10psi, now we know that's wrong.

 

The above photo suggests perhaps more than 2.9bar even based on the transition from R15 to R16 & i'm guessing it'd then increase when changing to R17?? No idea if the tyres being stretched would change anything??

 

But with 2.9bar being 42psi (sorry i've always worked in psi, not bar), isn't that really quite a lot?

 

Still, as those reading this will be more knowledgable than I ... what do you say?

[richierich37 236]

I run my 17's at front 38 rears 36

Sent from my iPhone using mind waves!

[Lukey. 381]

Bloody hell that's high isn't it? I run my 17s at 34, I had mine at 36 but found that the cornering is much better at 34

[richierich37 236]

Bloody hell that's high isn't it?

Is it?!?! Once the car is restored I might just let a couple of psi oot then! :-)

[cornishvr6 52]

when i was running my 16's with slight stretch with an unloaded car i ran 32 front 30 rear or if it was loaded up 34 front, 32 rear.

 

Guess its mostly down to tyre sizes etc..