Sosodef79

iTrader: (1)

Just got my wheels put on and I'm not sure what the PSI is supposed to be.

My Specs are

245/35/20
275/30/20

My wheels are 20x9 in front 20x10.5 rear.

I have Sumitiomo HTR Z III. The tires themselves say 50PSI MAX. The guy at the tire shop said he put it in the computer and it told him to put:

31 in front, 33 in rear. When i went to get my alignment today they put it to 40PSI before alignment. How do i verify what is the correct pressure?

Thanks for any help!

yardie876

I asked my shop about this and they said to fill them up with the same manufacturer psi specs listed on the door jam.

SNiiP3R

iTrader: (3)

You are running low profile tires now, so the more pressure you put the more protection you will have. 38 - 39 psi is good enough. With your specs, I personally would not run anything below that.

Sosodef79

iTrader: (1)

Aren't the door jam specs based on the stock rims and tires?

Sosodef79

iTrader: (1)

What's up man thanks for your input. Weren't you running the same wheels? Vssx step lip wheels?

yardie876

That's what I asked them too and they told me to maintaining that pressure is fine. I'm running 37 in the front and 38-39 in the rear cold.

Sosodef79

iTrader: (1)

Cool thanks for your help, Looks like most peeps are running about 38 here.

KB350

I'm running the same size tires you are except they are Hankooks and Discount Tire Direct told me 37 front and 36 rear and have had no problems and a smooth ride.

JEFFOS69

iTrader: (1)

You're fine with 40 - personally I would probably run in the 43-45 if your max is 50. Better mpg and better handling than having softer tires due to lower psi

LexRuger

I'd do low 40s. Make sure you air them when the car is cold.

Schmexus

I run 30-32. The ride is too rough any higher. Mid 40's is crazy. I couldn't imagine how rough that must ride on these cars?? Especially with low-pro tires.

LexRuger

With plus sized wheels, the tire's sidewall is shorter so the rim is closer to the ground. Higher PSI makes the sidewall stiffer which can reduce damage from potholes.

Schmexus

Making an already stiff sidewall even stiffer makes a rough ride. We don't have potholes out here so I guess I'm more worried about ride comfort than wheel damage.

LexRuger

Nothing wrong with that