Im running them on steel.

 

Steels

 

this is why the MR kit has a different wing…

No, it shouldn’t move or flex

 

any photo of the rears as well?

 

I am not a fan of that approach. The sidewalls on the Cup 2's are soft enough as it is, no need to make it worse by having lower pressures. The Cayman chassis benefits greatly from a stiffer sidewall tire as it removes a lot of the lateral movement from the rear-end.

 

You do not know better than Manthey Racing.

 

Are Manthey tire pressure recommendation hot or cold?

 

If I understand the vid correctly they are hot.

 

Wow...I could understand those pressure cold but hot sound kind of low for a Cup 2.

 

I didn't say I know better then, I said, I DO NOT LIKE THAT APPROACH BECAUSE............ etc., etc., etc.

 

Those numbers IMHO are a little high for cold as well. But we have to remember that Manthey is mainly interested in NBR and not other tracks.

 

The gt4 was 29/33 psi from memory

this isn’t far off that

The best test is pretty simple… drive it, see how you get on

i felt the car would understeer if the front pressure was much higher

 

Yeah, that is what the door jam says. I used 30/32 COLD when I was on the Cup 2's as the added front 1 PSI gave a little better initial turn-in and it gave the rears 1 PSI less to deal with when hot.

Now I am on Goodyear SC3 and with those stiff sidewalls, I run 28 COLD all the way around and that is perfect and STILL provides better lateral stability. I will do the same with my upcoming AD09's as they also have stiff sidewalls.

 

GT4 nameplate is 29/33psi or 2.0/2.3bar. From my experience I start to get huge understeer when the fronts get above 2.1, rears are less sensitive since it is so front limited.

Can anyone with a GT4 RS show us the nameplate? Is it the same or different? Either way if Manthey are recommending 1.9/2.0 then I would be taking their words as gospel. The main problem is your starting pressures need to be very low so it needs some babying to get them into the right window without damaging the tyres.

GT3/GT3 RS pressures from Joerg Bergmeister reinforce this as well.

 

That's probably why they start them so low is that they are set up to run The Ring, which is a 7+ min course and you can't get out after a 2 min run and bleed down pressures.