I have a FWD car 15X7 wheels and 205/50X15 tires. What tire pressures are you looking for hot with these tires? And what kind of pressure gain do you get cold to hot?
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I have a FWD car 15X7 wheels and 205/50X15 tires. What tire pressures are you looking for hot with these tires? And what kind of pressure gain do you get cold to hot?
completely different car configuration and tire size, but I start about 24 cold, roughly 30 hot.
I also use "wet Houston TX air compressor air" in mine so the pressure rise is probably higher than someone that would use nitrogen or dry filtered air.
I've found them to be pretty tolerant of pressure though. turn-in is still pretty sharp down to about 22psi, turn-in and tire life gets better as you go up in pressure, but grip drops as well. for my car, it's a pretty good compromise about 29-30psi hot.
28 cold, 36 hot.
That seems way too low to me.Quote:
Originally Posted by Matt93SE
Funny you should mention that Eric. We had a 200sx with a SR20DET at out last PDX, and discussing pressures with him. He's running low 20's getting up to high 20's and being good on NT01's. My guess is they're running less camber because their not struts in front with lots of air volume per tire for not much weight.
Damn my short memory, I can't remember what we ran on the SSC Civic. BFG recommends 35-37 psi hot for a car that is 2300-2600 lbs. That sounds about like what we ran (in fronts).
Integra '98 - 29 cold all corners.
Hot target will work best around 36-39.
Lower on a real light corner.
The cold # is just a local/ambient starting point. Has no value for racing.
The car rolls better with higher pressures. Thus, Ihave picked up a few tenths with higher pressures and lower spring rates.
I've been running 35-37 cold on the car and still get more tire roll then I think I should. I haven't check the hot pressures as the few times that I did any testing I was by myself and didn't think checking the hot pressures after I parked the car in the paddock and got out of the car was any use.
I'm running #450 front and #475 rear CO springs. I'd like to find some #500 for the rear but haven't come across any used. I prefer 6 or 7 inch but I can use 8 inch.
I'm off to road America in a couple of weeks.
What are your hot tire temps telling you?Quote:
Originally Posted by jimbbski
Mark the sidwalls and keep at it . Just enough air to keep off of the side walls.
If your marks say add air, go up 2# each time and remark.
450 / 475 is not out of range.
@ 475 I think that you can raise the rear pressure up to almost 45#. If not, swap the springs.
550 rear can work but needs less pressure, thus rolls less good. "less good" HA,
I am trying to put less rubber on the road when straight ahead.
Edit. I take pressure readings in the paddock. The temps will equalize across the tread face, but the pressures will stay pretty high.
As long as you take the pressures around the same amount of time from the track, the readings will give a valid indication of dynamic pressure. You either need more , less or are good. the actual value is not important. If you find that you 50# to keep it off of the side walls , than you need more camber of course.
I run my cars sideways up the straights, (the LR toed out,) so I often need 4 different pressures.
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Do you have any feel for how they compare to Hooisers in rolling resistance? And, what do these tires like for camber compared to Hoosiers? I typically run 3 deg front and 2.75 rear, too much on the rear I know...
I'm considering trying these for an upcoming race at Charlotte.