What tyre pressure do you recommend for track event (road course) on tires:
- front : 225/50/16
- rear: 225/50/16

For everyday use I use 22psi all-round, but what about for the track ? Something like 28/24 or similar ?

Thanks!

 

You should be running 32 psi for daily use!

Start running the track event with 32 psi front/rear. After a run session, check to see if your tires are rolling over too far (there will be scuffing down your sidewall). You want to be running a tire pressure that has the scuff pattern at the edge of the sidewall/tread.

FWIW, I have run all my auto-x and road circuit events at 32-34 psi. 22 psi is for drag racing, man!

 

I like to run a little higher pressure than Rynberg. I run around 37/35 front/rear when hot. This is for street tires. Race tires are a whole different world. They vary quite a bit, so one tire might run best at 20psi while another needs 35psi. I found that my BFG race tires worked better around 20psi. The Yokohama's liked more pressure. Rim width makes a big difference too.

So, the answer is: Everyone has their own preference for what works best. Also remember that the tire pressures will be higher when hot.

 

Thanks for pointing that out Adam, the pressures I listed are cold pressures. Usually, my hot tire pressures are more like 35 psi.

 

Bah... I think I have made a conversion error
1bar = 14.7psi, right ?

I'm running 2.2bar so that is about 32psi or there about, right ?

I know about the tyre wall issue, but just wanted to know if there is any good level to start from.

Last time I ran 2.8/2.4bar on hot tyres and I think the rear tires pressure was too low.

 

Mid thirties is a good place to start. If you are using bars, you shouldn't be driving

 

Hey adam, did you ever got to dyno your car ? I have similar setup as you sans IC and am wondering what hp numbers to expect (I also have midpipe with restrictor inthere) ?

 

I have not dyno'd it. I would expect around 300 rwhp at 13psi. That's just a guess.

 

Long, long ago is SCCA showroom stock class racing, we used tire crayon on the edge/sidewall of the tire to measure rollover in cornering. What we strived for was the minimal tire pressure to avoid rolling onto the sidewall.

 

you can use shoe polish to see if you need to increase your tire pressure, well, that's what i read, but don't really know exactly how to do it...anybody wanna explain to clueless me? :p

 

depends on the tire and the compound....this is my track setup:

I run my track tires (kumo victo racers) at a very low psi because they purposly have very stiff sidewalls, so I can go down tot he 30-28 range for max grip.

I run my street tires much higher (at the track), like 38-40 and get better grip, but if I go over that then I start ice skating since it bows the tire out in teh middle and I dont get the edge of teh tire for cournering grip.

On the stree I run them at their rated pressure.

Im no expert, but just my experience.

 

1 Bar = 14.5 psi, thus 2.2 bar = 31.9 psi ~ 32 psi. I also run 32 psi cold tire pressures, street or track. I have 255/40-17 tires on 9 x 17 wheels, though.

Note that Bar and kg/cm^2 are different psi:

1 kg/cm^2 = 14.22 psi

 

Anyway I ran 2.4bar on hot tyres in the back and 2.6bar on hot tyres on the front at the track. I think I could even go lower as the car felt as it was a bit tip-toeing through the corners - I didn't have full confidence in it. Only ran 1sec faster then in my CRX delSol (160hp). But then again, I only have it for like 1500miles so far. Need to get used to it (to have confidence to do trail-braking and sooner acceleration).

 

I like to use chalk. Take a piece of chalk and mark the tires. Make 3 marks on each tire about 1/2 to one inch wide. Mark them on the outer part of the tread, and going about an inch up the sidewall of each tire. Make note of your tire pressures before your run on the track. After your run, check the chalk marks to see how much has been scrubbed off during the run. If the chalk is scrubbed off too high on the sidewall, then you are rolling over too far, and need more air pressure. If the chalk is not rubbed off at all on the side, your pressure is too high. You want your pressure to be set so the tire gets to the point where it just rolls over a little.

Keep in mind that some race tires are constructed with squared shoulders, so that they can't roll over.