I was running 41 lbs for city and highway driving in my previous 255/35/19s, which seems high but its the pressure printed on the door jamb. I was gonna go with 39 and test. Any recommendations?
Stick to what’s on the doorjamb. The only time you should ever experiment with the pressure is if you are fine tuning handling for autocross, drag, etc.
More psi = more power right?
Oh sorry thought I was in the B5 section…
The Saki troll! love it 
I went with the 39 lbs (B6 S4 235/40 18) recommended on the door jamb and wore out the center of the tread. 95% interstate miles. Gonna try 36 when I get new shoes in the spring.
The door jamb placard is irrelevant because you have changed the stock tire size and brand.
I recommend asking the place you got the tires from to get the correct pressure. There are charts for that.
Generally, wider tires need less pressure, but shorter sidewalls need more, so it may end up being a wash, but this should still be researched properly.
Tire rack disagrees with you. Not saying I know any better, I’m saying it appears they disagree.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=8
“Therefore it is the vehicle manufacturers that ultimately determine the tire inflation pressures they believe best fine-tune the tires’ capabilities to their specific vehicle makes and models.”
“Therefore when checking and adjusting tire inflation pressures, the “right” inflation pressures are those provided by the vehicle manufacturer, not the “maximum” inflation pressure branded on the tire’s sidewall. The vehicle manufacturer’s pressure recommendation can be found on the vehicle’s tire information placard label, as well as in the vehicle owner’s manual.”
Then again, I suppose if you aren’t using the specific size assumed by the vehicle manufacturer I suppose it all goes out the window?
Yeah, I read that before I posted. There is definitely some conflicting info out there.
Tire Rack says nothing about different sized tires though, right? So they’re not really disagreeing with him. They’re talking about stock sized tires presumably.
Yea, although I’m not completely sure and it was a bit unclear to me as I was looking for information on the subject. It seemed like there is fodder on both sides of the fence.
Got me thinking though, because what musanoadsaba says makes sense in many ways if thinking about pressures and contact area vs load. It’s something I had never really given too much thought to before and I have always gone with the manufacturers recommendations for street tires but that could be one of those “rule of thumb” that is not actually universal, *and is meant for a specific tire.