what should i set the tire pressure at? the tire says maximum psi of 51. if this is the case should i set it to 51? 49? 47? 31?

i have dunlop 5000 s or something like that.

 

somewhere in the neighborhood of 5-10 psi less than the max. So around 41-45 psi. This is prob. on the hi side. 35-38 psi is prob. ideal for road comfort.

 

I'm on the 17" OEM with run-flats and tire pressure is set at 32 on mine....

 

32 psi .................................

 

Whatever the suggested psi is on your door jam is where your tire pressure should be (don't rely on the sidewall).

FWIW...a few weeks ago before taking a 375 mile trip (L.A. - Phoenix), I set my pressure 'cold' to 30 psi and departed at 8AM. Once I reached Phoenix, psi increased to 37 (average speed was 72 MPH). Didn't drive my car for 26 hours. Before heading back home, tires were at 32 psi (Phoenix heat???). Set them back to 30 psi, Upon my return, tires were at 35 psi.

I conclude the drop of 2 psi coming home could be due to a late afternoon departure and averaging 61 MPH.

 

The side wall don't have a suggested psi, it only have the max.

Bush, was that filled with Nitrogen gas or regular air?

 

Regular air (if you consider L.A. smog 'regular' air).

 

My mechanic suggested +2 for the front to cancal out our 52:48 weight difference.

Also I remembered seen it somewhere in the news that you could improve the gas mileage by putting additional 5 PSI to the tires; so I am running at 40 FRONT 38 REAR.

 

The ideal tire pressure is written on the inside of your door jam along with tire size and maximum weight suggestions.

It is to be noted that whether or not the tire if filled with nitrogen, the pressure will remain the same as that which is noted within the door jam. The only advantage to nitrogen is that the pressure remains constant in a wider temperature range, whilst air expands or contracts under hotter or colder temperatures. Nitrogen remains relatively constant pressure-wise. This promotes even tire-wear, among other things.

 

I have my tires set to 44 psi for bent dent protection and wear characteristics. It does affect the ride a bit