Autocross tire pressures

I'm curious as to what you guys run for tire pressure when autocrossing. Please list your tire size too.

With 245/50-16s all around I ran 45 front and I think 35 rear. It was my first time so I didn't really know where to put them. I had to raise the fronts a bunch to keep them from rolling over. With Corvette runflats (245/40-18 and 285/35-19) I ran 32 front and 25 rear, the tires were very stiff and needed lower pressure to keep traction. These year I'm running Bridgestone Potenza RE760 245/40-18 and 275/35-18. I'm trying to get an idea where to start them at. I've noticed the edges are rounded so it seems you can run less pressure without having to worry about wear out the edges.

this may be totally irrelevant to you but on my rx7 i run 30psi hot front and rear on a square 10 year old 275/40/17 RA1 setup.
~300 hp ~2800 lb.

this year i'll be on a fresh set of NT01s and hopefully closer to 2600 lbs...

when i ran my gf's bone stock 07 fit i had to run closer to 45 psi all around just to keep the 195s street tires from rolling over. it had a lot more grip with lower pressures but i didnt want to kill off the tires.

i dont remember exactly, but the last track day i did with the s10 i was running roughly a 35psi front and a slightly lower pressure rear with a 275/40/17 g-force sports up front and 245/45/17 g-force sports in the rear.

My truck is probably 3500 lbs (maybe more). With street tires (Eagle F1 Supercar of Toyo T1R) I'm generally around 38 in the front and 32 in the rear.  I sometimes go to 30 in the rear but it starts to feel 'squirmy' and gets hard to control when the back end breaks loose. 

With race tires (275/40-17 Toyo R888) I run 35-36 front and 32 rear.  I ran some older model Bridgestone potenzas a few years ago and IIRC the sidewall was really stiff compared to the Eagle F1's I ran before them - I think I ended up back around 36 in the front for those too.

I also blow off quite a bit of pressure between runs.  My fronts will gain almost 10 psi after a 2 or 3 runs.

Yeah I remember my tires jumping up in pressure after a few runs. With my new tires I run them at 35/32 on the street. They have a pretty stiff sidewall so I feel basically no tire flex when cornering. I think in the next autox coming up I'm gonna leave the rear pressure alone, and see if I can get the back end to slide out, then adjust them. Last year I never really pinned it through corners just because I assumed the back inside tire would start spinning. The only time I got the back end to come around at all was when it was raining out. Even the front tires I only got to 'squeek' (not squel) once when going through a sharp slalom. I feel like I can probably drive a little more aggressively this year with the grippier tires.

Do you have an open diff?  Even a G80 is better than completely open and it really helps to pull the rear around the cones.  If you're driving well you should definitely hear your tires working on every corner.  You won't achieve maximum cornering grip until your tires reach a certain slip angle so if they're not making a bit of noise you can take the corner faster.

Do you have an open diff?  Even a G80 is better than completely open and it really helps to pull the rear around the cones.  If you're driving well you should definitely hear your tires working on every corner.  You won't achieve maximum cornering grip until your tires reach a certain slip angle so if they're not making a bit of noise you can take the corner faster.

does the g80 actually help at speed?
I havent figured out when it disengages but aside from the launch, i assumed the g80 would behave as an open diff for an autoX.
also some tires are quieter than others. all seasons make a ton of noise but my rcomps are usually squeek free (unless fresh poured asphalt)

My g80 disengages at about 20mph.

After about 4 years I forced myself to change my driving style to optimize the G80.  If I knew I needed the rear to lock to rotate more in a tight turn I would get on the throttle before I started the turn to get it engaged.  It took a while to make it second nature because it's a really uncomfortable feeling to accelerate when your mind is screaming at you to brake but it really made a huge difference in my corner exits.  If you don't get it locked before entering the turn, and stay on the throttle to keep it locked, it's just a one-tire fire on the exit.  It didn't work every time but more often than not it helped.

The courses we run around here tend to be fairly tight compared to the videos I've seen of the good guys events or even the ones I ran on the air field when I lived in Western Canada.  By the time you need the limited slip here you're going slow enough for it to engage.  I have a Torsen now which is 100X better.

aside from the launch my g80 never locked again during my ice racing events.
luckily i can spin one of my front tires to pull me into a turn though.

I have a G80. A lot of times around corners it takes a second or two for it to actually lock up though.

245/50-16s I run 45 front, 30 rear too. The 45 up front is too keep it from rolling over. I mark the edges so I know where they are rolling to. They will go up ~5 pounds after a hard run or a session. So, I set them back to 45/30 when they are warm after the first set. The 30 rear is high, sometimes I go down as low as 26 to get it to fully use the whole tread and hook up on corner exit a little better. I have a TrueTrac diff.

So to update, I found the sweet spot is 35 front and 30 rear for the 18s. I've been driving a lot harder this year and probably could have added a few pounds to the front to help them wear better, but I was happy with the handling and grip so I left them .