Correct Tire Pressure

[die s-klasse]

Originally Posted by Jayhawk

I went from OEM 16" 225's to 245/45WR-18 Goodyear Eagle F1 GS-D3 XL front and 275/40YR-18 Goodyear Eagle F1 GS-D3 back, and Luke recommend 36 psi front and 32-34 psi back. You probably need to go a good bit higher w/ 20"s.

thanks jay as well.
i think max rating is at 40psi.
so i shouldn't go too close to 40?

[Mercedes Benz of Florida]

Originally Posted by ivyknoll

I recently bought new tires for my 2002 E320. The tire dealer set the pressure at 40psi as the max rated psi for the tire is 44. He said they will run cooler and therefore last longer. However, the car rode like a truck and the handling seemed almost unstable at interstate highway speeds. So, I lowered it to MB's recommended full load pressure of 28 front and 34 rear and the ride and handeling are now as they should be.

My question, who's really right? Seems that tire dealers and auto manufactures have never agreed on the correct psi.

The correct one is the Manufacturer.
They are the sole authority in these matters.
And the 28 Front/34 Rear is right.
I agree your PSI was way too high.
( now in my case, I bump up the PSI +5PSI in front and rear )
That's a personal choice and there is no degradation in handling or
responsiveness.

[Luke@tirerack]

Originally Posted by Mercedes Benz of Florida

The correct one is the Manufacturer.
They are the sole authority in these matters.
And the 28 Front/34 Rear is right.
I agree your PSI was way too high.
( now in my case, I bump up the PSI +5PSI in front and rear )
That's a personal choice and there is no degradation in handling or
responsiveness.

a couple of things

there is no sole authority ... the Mercedes OE recommendations are a compromise between handling and ride quality which they feel will be best suited to a majority of drivers while maintaining proper load capacity.

and your personal +5 psi would not only NOT degrade the handing and responsiveness it would improve both