Hello,

I've searched for reccomended tire pressure for the stock potenzas and have seen from 30-40psi cold. I have an 06' with 18 inch wheels and the stock potenzas. I did a day at Thunderhill and set them at 34psi and they climbed to 41psi once they got hot. What is most reccomended, as 30-40psi is a big strech?

I searched here on the autox/road section and as I said the diferrence is so big that not sure where to set them.

Thank you.

 

Thunderhill is open road racing? 35PSI cold. Don't worry about hot.


For autocross I run 45PSI all around. I put paint on the tires. At 45PSI the tires run flat on the treads as they should.

 

Dave, How does that tail end feel... I usually run the rears at 32... The fronts on streets is usually good to start around 40 and see what kind of rollover onto the sidewalls you have and maybe increase it. I ran mine at 44 on street tires...

 

Thanks guys. I'll try 35 at thill on the 20th.

Kirkster, asre those pressures for autocross?

 

When I ran, I did about 32-34 psi in the rear and 40-42 in the fronts.

 

This is what I'm talking about.

Is talking about tire pressures the same as talking about oil/politics/religion? hehehe

 

I've been running 36 up front and 32 in the rear, seems to be about the best grip I can get out of the stock tires without scuffing up the sidewalls too much.

On the street I run 33/34 front and 31/32 rear

 

Are these autoX or Road course pressures?

I'm interested in Road course pressures. looks like I'll be doing 35/35 f/r

Thanks again.

 

How can you not worry about hot ! That's what's important !!

 

+1.

Determining a cold pressure is just a starting point for getting to the hot PSI that you want to run. And depending on track/weather/etc, the cold PSI to start at in order to reach the desired hot pressure will differ (sometimes dramatically).

 

LOL.

Weekend racers, like myself, should keep things simple. Pro racers are concerned with tire temperature. Surface temperature is measured with a Infrared Temp Thermometer Laser Gun such as the one above.

 

To be accurate you want to use a tire pyrometer probe to check below the surface of the tire. For me, the infrared is good enough and can be used for brake and engine components...

 

When I mention 'hot' pressure, I'm basically just talking about the pressure when the car comes off the track, and the tires are hot. This is the most basic tuning option available, and it's one that pretty much anyone can use.

I agree that taking specific temps with a pyrometer across the face of the tire is somewhat more advanced, but anyone can set pressures when the tires are hot (i.e. just after a run).

 

So for the stock potenzas, what is a good hot pressure coming off the track? 41psi all around?

Not trying to beat a dead horse, just trying to get good info.

Thanks again.

 

I found that 40 hot was the highest I could go on the stock tires without them starting to get really greasy and beginning to lose grip dramatically.

 

just did a track day with a z i borrowed from my sister and also found 40 psi was too high for the stock tires. i lowered them to 38 hot all around. they felt better but would try 36 or 37 if i were to track her car again.

 

I ended up seting them at 35 cold and then i set them to 40 hot after the first session. Worked fine.

Thanks to everyone that replied.

 

I agree with Julian, I have found that 38 psi hot is the best grip I can get with street tires or R-compounds for a Road Track.
Take your cold pressures and after 20 minutes, see what hot tempertures they become.
Also, a pyrometer is a great tool at a very low cost and will help you determine your ideal tire pressure. It will also tell you how to set up your alignment to get more grip!