38 psi too much for Hankook Dynapros?

Got my Dynapros installed on Friday. They left the shop with 31 psi in them, and they looked way low. I pumped them up to 34 front/32 rear and they still looked low. I pumped the fronts up to 36 and they looked OK, but they still have full tread-width contact and show a little bulge at the bottom. I'd like to go up to 38 front/35 rear, I think that will make the contact just about right. Question is - will 38 psi hurt anything? Ride quality at 36 is still just fine, and I'm doing 99% highway travel. Max pressure is 44, so still well below max. I'm just confused because I see guys running 32 or so in these tires and there's definitely too much sidewall flex at that pressure in my DC 4x4.

Tires are 265/75R16 Dynapro ATM passenger tires.

 

Chalk Line Test...

 

I ran 42psi for a while. Never did anything to the fronts but wore down the middle tread a little prematurely on the rears.

EDIT: Not even bad at that either. Just the small line that crosses the middle tread in a horizontal zig-zag. Rotated them before it was over the top

 

What does it say on the sidewall of your tires?

 

I chalk tested mine and settled on about 34 psi

 

X2

every rig is diff, more weight and such. you need to set it up for your rig

over inflate you kill the center of the tread
under inflateyou kill the outside of the tread

 

A helpful piece of info- but only as info. The inflation value on the tire is usually a MAX...NOT a recommended. Recommended values are based on a specific truck with a specific set up...

 

Dirt wears off evenly across the treads, but I don't think the chalk line test will tell you your tires are too low until they're low enough to cup. I have nice even contact on the ground but just more sidewall flex than I'd like. Obviously if I bumped it up to 38 and then lost contact at the side lugs, I'd drop back down to 36. I'll probably still chalk them and see.

 

It says max pressure is 44 psi, as noted.

 

The chalk line test is NOT a final answer. It's the starting point...The amount of sidewall flex you like won't be testable any way other than you looking/feeling it.
And you can look at heavier weight tires...More plys = stiffer.

 

Great input - thanks. If I had realized the P-rated tires would be so flexible, I might have opted for LTs. At $610 all in including mounting and balancing though, I couldn't resist trying. The ride is really nice, even at 36 psi, so I definitely can't complain there.

 

Oh I agree 1000x. In order to give him sound advice this is crucial information to start with, than depending on his driving style, hobbies, and setup on his truck we can go from there. I would never max out my tires under any circumstances.

 

Look on the inside of your driver's door and it will tell you what the factory recommends to run also that is what the sensors are set at.

 

Right - but 30 PSI as noted in the doors is obviously not the right pressure for these tires. Different tires obviously have different optimal pressures. I doubt they'd last 15K miles with as much flex as they had at 31.

Sensors are going in an air chamber, but that is a good tip - some people would have sensor pressure to consider with their setup.

 

And (at least in mine) you can reset the sensor pressures with the button under the steering column...to any pressure you want.

 

Same

 

I set mine anywhere from 36-38psi each and the wear is even, the ride is nice too.

 

Thanks - I'm still at 36 front and bumped the rear to 34. I'll keep a close eye on the wear.

 

IMO you are right where you should be 36-38. Don't forget the air is part of the tire's construction. Also IMO you shoud run all 4 the same because your weight distribution on that truck is pretty even right? I am thinking from my own truck but then again I have a 200lb shell back there too.

 

No, at least on my truck the rear tires have less sidewall bulge at 34 PSI than the fronts do at 36.