pressures

[Erv]

ok, it's been awhile since I have had rcomps, what kind of pressures should i start at?

[BoostedFD]

75psi...What do you normally run?? I'd probably start around 40+ and come down.

[Erv]

i seem to remember rcomps running lower pressures than streets

for the record i run 38/35

[revvhappy]

I have no idea what type of car you drive. For my FWD, I ran the Hankook r-comps at 37F/26R. AWD and RWD will be quite different - I ran the low rear pressure to get rotation.

[TouringBubble]

Erv, if you like the lower rear pressure, start at 40/38 and bump it down. You'll probably end up around the same place though. you could ask to borrow a temp gauge from someone if you want to be really technical.

[EvoLady]

10psi i. start from there. hehehehe

[BoostedFD]

On my car I run like 28/30, but on my Eclipse I ran 38ish, I think, because it would roll over on the fronts if I didn't. I figured the STi to be alittle heavier but more balanced I say start around 40 and see what it does.

FWIW lower rear pressures should get less rotation on a FWD car.

[Focus]

There's a mystical "ideal pressure" which always changes with temperature, surface, and the moon phase. Taking the rear tires anywhere north or south of there will make less traction and more rotation. There's pro's and con's to both.

[claym]

Remenber that higher pressures also mean a higher effective spring rate (from stiffer sidewalls) as well as a decreased contact point.

[Welacey]

When AB got FTD in my car we were down to 18 lbs.

[BoostedFD]

Softer means more rubber contact patch with the road. To soft make it feel funny and do odd things, but if you can drive it there and feel comfortable go for it. Harder means exactly what Clay said.

[Focus]

18psi is for a drag race. I suppose that's about what a large autocross looks like to a miata?

I don't know about AWD'$ R-comp'$ pre$$ure$. Some of us make due with FWD and street tires, lol. In my experience, ideal grip was getting too close to the max pressure to comfortably tune upwards from there.

[TouringBubble]

18 psi isn't for drag that is around 8-10

[ZX3Focus]

A trick I've heard:

bring a stick of chalk to grid. Draw a chalk line across the tread face and a little onto each sidewall before each run. Adjust pressures up or down until your driving habits and the current conditions clean the chalk off all the tread face but leave it on the sidewall. If chalk is still present on the tread face, lower the pressure. If the chalk is gone from the shoulders and sidewall, raise the pressure.

Of course, at BRC, you can pretty much see the scuff marks added by each additional run. The chalk might not be all that necessary.

[Focus]

I've heard of using armor-all on the sidewalls for the same purpose. I think that's probably more for street tires, as the square shoulders and stiff sidewalls of R-comps won't roll the same way streets do. Worth thing that could happen is you have the cleanest race tires at the track?