Tires pressure, make and compound

I am running a road course with a Formula Mazda.I am using Hoosiers 25 compound, 13 lbs in from and 12.5 lbs in back. Are Hoosiers the best choice for non spec racing? Is 25 compound correct? Finally; am I beginning with the correct pressure?

you really need to look at some data to determine if you're starting with the right pressure. what are your temps measured across the tire after a session? what is the pressure in the tire after a session?

in absence of a bunch of other details, if you aim to achieve approx. 21lbs hot pressure and tire temps that are even across the inside/middle/outside of the tread, then you're in the ballpark. probably aiming for surface temps between 185-225 deg F. hoosier 25's are quite soft, not sure that's what you want to run unless you have a pretty good tire budget and only run short stints, or maybe if it is cold all the time where you are.

When I ran Hoosiers I preferred harder compounds unless it was very cold out (<60F). R35's or R45's if you can get them. If it gets hot the 25's will not last long and if it's very hot they'll blister no matter how good your setup is.

I usually went for about 19-20lb hot on most tracks.

Starting pressures were typically in the 15-16 pound range.

Thank you, it looks like I am in the ballpark. I am starting with a lower temperature, but end up around 21 pounds hot. The temp is pretty even across the tire. However, it sounds like I need to go to a higher compound tire. Thank you for the help.

are you compressing air and thinking it's dry or getting your fill from nitrogen tanks which you know is dry? starting pressures will be different

vote for 35's here

I'm using compressed air. Today we began at 15 pounds and hot at 21 and it stuck beautifully. We are ordering 35 compound not. Thank you for your advice.

Ordering 35 compound now. Should have read my previous post better. Is filling with nitrogen that much better?

Nitrogen is much more predictable. Compressed air varies in moisture content. You're gaining 6 #'s of pressure with air one day, maybe 4 the next. When you get consistent lap times, a pound of air pressure, either too high or too low, can make or break your race.

That helps a lot, thank you.