SLegacy99

Check the pressure today, 34 PSI all four tires. The placard told me 30 PSI so not sure what to keep it at. Do the dealers over inflate the tires to increase mpg?

jim256

It seems the list consensus is about 32-34, your preference. Some like it even higher but you need to monitor wear in any case. Dealers set them when the car is prepped for delivery, it could just be temperature or gauge variations that caused a small change to 34. Sometimes you'll see 40+ when the dealer did not decrease the initial factory fill, which supposedly reduces flat spotting in shipping. Your dealer did what he should, but you should check them cold regularly, set them for your preference.

MadloR

Depending on the tires, the factory GoodYear's are horrible. Very poor tire wear especially the inside tread. Let us not forget, the 400H is a real porker on the weightscales, and I firmly believe the factory vehicle is undertired.

Many, including myself do run higher psi, and I have had so far great success at 36psi. You may experiment, but be careful and monitor the tire for uneven wear.

Cheers,

MadloR

Lexmex

I have run my Michelin CrossTerrains at about 39/44 max for a while. I use nitrogen now, but haven't seen any issues except for improved MPG and faster 1/4 mile times.

SLegacy99

Yeah, theyre Michellins. Thanks for the advice....I have no idea what I'll do.

Lexmex

what is the max on them?

jim256

The max pressure is embossed on the sidewall. 'Not recommended for normal use, it's a maximum per the tire manufacturer.

JimsGX

The OEM Michelin S8's show a maximum inflation pressure of 35psi on the sidewall. I've been running mine at 33psi and am pretty happy with that setting. On one occasion, I pushed the vehicle hard into a corner and could feel the sidewalls folding under.

joedaddy1

iTrader: (1)

oh god... now y would u do that!

Lexmex

I assume you are running them at 33 psi cold...have you ever measured them when hot?

I have ran my CrossTerrains at near the max when hot and I had issues off the line and downrange on my 1/4 mile strip here, where it felt like I was sliding backward a little as I couldn't get traction.

On a track day with my buddy Michael, he is the one with the RX7 on my car domain page, the organizers had everyone put their tire pressures near max, about 40 psi on my friend's car, to prevent beading. Now that is a race car and in that case, he was having terrible issues on the 3 turns that comprise the Autodromo Hermanos Rodriguez here in Mexico City. He had to drastically lower them to get any traction. This was a video of some of the cars that drove on that day, http://www.youtube.com/watch?v=WWr5GTJsKiE

JimsGX

No, I've never checked the pressures when hot... I looked at your video, was that an oval track?