What does everyone usually run in thier stock tires cold ?

Currently I run about 33 cold which gives me about 36 hot

Would be interested to see what the average is

 

41-43 atm
thats after auto-x and i didnt let tire pressure out
auto-x was like 47ish hot lol

 

35 psi cold

 

more psi = better gas milage?

 

I keep mine at 36 psi when tires are cold. I believe the tire pressure for stock 17's should not be inflated over 40 psi...correct me if I am wrong.(that is what is stated on the tire side wall.

 

In general yes as that will mean that less of the outside of the tread blocks is touching the ground. That means less tire contact patch and less friction but also less traction which is where the trade off comes in.

 

For 18s, recommended is 35 (cold) which is what I run.

 

+1

 

I am going to 35 cold

Thanks for the input

 

Yup, what he said... which also basically means you're tire is "rounded" in the middle so your middle tread gets worn but your outside tread doesn't... causes uneven tread wear in the long term if you always keep it like this. Hmm, with the Z's negative camber tho... guess you'd still get half a tire's worth of wear being from the inside edge all the way to the middle. Just a thought.

 

the reason gas mileage is better when there is more air is because the circumfrance of the tire is larger so it rotates less

 

I run 40oz cold, Mickeys.

 

The reason the gas mileage is better at higher tire pressure is because of less rolling resistance. The tire is harder and does not flex as much, thus it rolls easier.

 

Just inflate your tires to 35psi (cold), and you will be fine. Ambient summer/fall temperatures where I live are above 90 degrees in August/September, and my tire pressure sensors show maximum pressures of 40psi after a few miles. That's good.

The biggest issue in the front tire feathering problem (other than mass hysteria) is that tire preasures are not kept correct. The low profile tires on the 350Z need to be checked AT LEAST once a week. If the pressure falls below 30 psi, you will have tire wear problems, even though your sensors don't give you a "low pressure" warning.

Driving a 350Z means never having to say you didn't pay attention.

 

what psi would i run on 20's?

 

Size doesnt matter. The car matters. When I went from 18-19 the psi didnt change. So on the Z I think no matter what size your using you need 35 cold.

 

+2

Pump up to near 40psi for track use.

 

I'm running 28 in the rears cold right now (dropped from 33 last night, haha) and about 30 in the fronts. I get really good traction though, . ANd my tires are already bald. Gotta get new ones after the winter so I like the traction.

 

Oh, I bought it used so the tires were already getting there wear wise, I don't spin them very often. Plus I have 27K on the stock potenzas in the rear.

 

Not to start arguments, but this is wrong. There is neglible difference in the circumference of the tire with different pressures in relation to distance/rev. It's the contact area as mentioned previously, leading to less friction force applied to the tires by the ground, and hence, less force the engine has to overcome.