CSR tire pressures?

[pethier]

Taking out the CSR 260 for an autocross practice day.  Wondering where to start with tire pressures.

 

New Toyo R888R tires 

195/50 R15 x 6.5” width  (fr) 

225/45 R15  x 8.5” width (rear) 

We expect temps in the 70s F.  Asphalt is in pretty-good shape at the Minnesota State Fairgrounds lot.

 

I have been using 20psi all around on my square setup on my other Sevens, using Yokohama A052 tires.  For 74PHIL that has been 195/50 R15 x 6.5” width (Prisoner wheels).  I have a set of 8" wheels on which I will probably go to 205/50 R15.

 

I have not had fresh tires on the Birkin until just now. Tuesday I put new 205/50 R15 Yokos on its 7" rims.  Those tires will go to the lucky person who buys the car.

 

As time goes by, I expect to switch the CSR to the Yoko tires to get legal in XU.  Only change is that the rear tires would change to an aspect ratio of 50.  For now, it's Exhibition class locally.

 

For the Practice day I hope to have both the CSR and the Birkin out.  MACs "over-70 drivers don't need to work" rule means I have six hours to do whatever I want.

74PHIL will sit out this event.  I am putting its passenger seat into the CSR.  My new Tillet seat will be a while getting here.

 

I can't wait to try out the CSR quick-ratio steering rack on a slalom.  I't's about 1.5 turns LTL.

[Croc]

On 15 inch wheels do:

front 19psi cold

rear 20psi cold

 

I think the CSR owners manual is a single psi off that. 
 

Experiment but you are aiming for about 25psi once tire is up to hot temps.  
 

If you ever go 13 inch wheels then it’s:

front 18psi cold

rear 19psi cold

 

I'm not a fan of the R888R.  After a few sessions you will find they go off and start to understeer like a pig.