I usually going out 29psi cold and i definitely feel roll. I have the 275's on 10" wheels.

Thats about all the clearance I have LOL. I will double check it though.

 

see post 27....

 

Seems like your ride height is really low. RC correction kit? If not, def raise that car up to help eliminate the dive. Also seems like you have very little droop travel, but it could just be the sway bar setting.

I would honestly try to raise it up and if you are punishing the front outsides, more camber, less bar. Is the car pushy?

 

I think NT01's and ST43's produce nearly the same braking force...

No rollover at 29psi hot? Maybe because you're running Hoosier camber. That pressure is way outside of optimum. I wonder how much your car would liven if you ran more air pressure and less camber to prevent tread rollover, as opposed to a lot of camber and lower air pressure.

 

Please don't take this the wrong way as I don't know you. How much experience with autocrossing on Rivals/Stones do you have? Ask some of the top guys winning nationals in any class about these tires. Better yet try it yourself. Many go as low as mid 20s, most around high 20s on proper camber cars. Limited camber cars go anywhere from low to mid 30s.

 

The R7/A7 pressure debate is still up in the air from what I've heard. I've seen some guys running 30 hot and swear up and down it's slick like grip. Then some others run the recomm'd 40 hot and claim it's not as comfortable but way faster.

 

I don't have much recent experience with autocross, stopped going after I could way more seat time per dollar with track days last year. But a tire is a tire. I can literally feel my NT01's stiffen up as they come up to temp from 27-28psi cold, to 38-40psi hot on track. Same thing for the re71's that I had on the car for one event and then sold.


It may be driver preference, but I simply am not sold on the low pressure train of thought. And neither is my chassis set up guy (Eladio, H1 Performance), who has a lot of autocross experience. When I did autocross, it was on Dunlop Z2's, and I ran about 36 hot. Was always good enough to be within 1 second of another guy in ASP on NT01's on a 60 second course.


Please don't take anything I'm saying as destructive criticism to your setup. I think we just have 2 different schools of thought here.

 

It appears alot has changed. If you are curious for yourself about what works in 2016/2017 simply google the GRM tire shootout articles.

 

I have experience with re71 at low pressure. Do not want, whether its hot or cold.

 

I would lean to agree on higher pressures. Rolling on the sidewall is no good. And thats what i feel at lower pressures on this heavy car

I correctly added the video up top. Check out how the car reacts.

 

Raising the ride height would increase CG and make it body roll more easily.
The car is pushy at low speeds.

I agree

I guess that remains driver preference. In my case it does induce tire rollover at low pressures.

 

I was going over some video from this weekend and my front end is diving hard even mid corner. Im also 3 wheeling at like 20 mph hard turns. check out the video below.

 

That looks like a completely reasonable amount if inside lift.

 

I have seen worse as well LOL. Do you see how much action in the front though, both up and down? Im gonna go with MCS's suggestion to increase front spring rate. This car is heavy.

 

UPDATE: I increased the front spring rate and increased tire pressure and the car changed completely! I had much more grip, no rolling on the sidewall and much less dive.

Props to Lex a MCS for the spring rate increase suggestion and the guys here for helping me realize that more tire pressure is the way to go on this car. Thats why its good to talk to fellow track guys. I remember the tire feedback feeling great with higher pressure but thought is would hinder grip. Learning lessons that dont cost money are awesome!

BTW! No tire blue on my sidewall after pressure increase!