I am going to run my slicks for the first time tomorrow and I am not sure how much air to start with. I have 225 - 50 - 13" on 7" rims. I was going to start at 40 PSI - what do you think?

 

Seems high for a race tire. I run my BFG Comp T/A R-1's at 31psi all 4 corners. But honestly, what works for one is most likely not going to work for others. The reason for high air pressures in street tires, is to prevent their soft cushy sidewalls from rolling under the rim during hard cornering. Race tires have much firmer sidewalls, and don't suffer from this problem as badly. I suggest you take some shoe polish with you, marking the tires on the edge or the tread into the sidewall. Then, as you make runs, adjust the air so that all of the tread is being utilized, but not the sidewall. Maybe someone who has experience with Hoosiers can give you some more pointers for those particular tires. Regardless, good luck and have fun.

Later,
James

PS. Don't forget to brake LATER for the curves. I have ran three events on racetires, and I still am scrubbing too much speed off trying to accomodate the street tires which are no longer there.

 

hoosiers require Higher pressures because the tire is lighter than khumo's or other race tires, 40 seems like a good start, for some reason I remember 42 psi beeing used with the hoosiers for ITA.

 

Thanks for the info. I've never used Hoosiers, so I didn't know they needed the higher pressures. Like I said before, I have never seem the same setup work on two different cars, even when both are 1st gens with similar mods, and the exact same tires. And again, have fun tomorrow.

James

 

on our ITA/7 race car we run 34 front and 36 rear.

Mike

 

stinkfist's pressures got me thinking for a second, then i realised that I forgot to mention that the ~ 42 tire pressure was for the tire when is hot. I should have specified earlier.

 

i've got kumhos in similar size and i was running mid 30s up front and mid to high 20s in back

 

Thats about our target temp when hot.

Mike

 

I run Hoosier autocrossers and I run at about 28/32 psi on my 225 45 13s...

just so you know...

 

Thanks Guys,
I will give you suggestions a try.