I have a 1999 Ram 4x2. I just put new tires on it and went from 245/75R16 to 285/75R16. Since the tire change and keeping the air pressure full to keep fuel economy up the truck rides horrible. I have rattles where it didnt and its just riding bad. If the road is rough the truck shimmies and slides around. What is the problem? Did the bigger tires just screw the whole thing up? I dont thing its the shocks as it dosent bounch and there is no vibration through the stearing wheel like its a suspession component. I just have no idea. Hope you have some ideas. I would hate to go to smaller tires as the bigger ones look great.
Thanks for any help.

 

Air pressure is most likely the difference a taller tire should help smooth the ride but if you changed the air pressure with change of tires thats the difference

 

Just how much is "full" air pressure?

 

if you just put on a new set of 285 load range D or E and have them at "full" pressure of 65 or 80 psi, then yes - it'll ride like a buckboard.

reduce air pressure to about 40-45 but don't exceed the max air pressure stamped on the side of the tire. if that helps, you can play with your pressures to decide how much you can stand.

 

I have it at the 65 PSI that it says on the tire. If I reduce it how much will it effect the MPG or will it at all?

 

If you just drop it 10 to 15 pounds, you won't notice the difference. Keep in mind though, that the heavier tires will probably drop ya a point or so.

 

Will drop it to 55psi and see what happens.

 

That much pressure in those tires will wipe out the tread in the center of them much faster than the rest of the tire.
You should try running about 48ish in the rear and 52ish in the front.

 

i only run 35 psi. maybe seem low to most but im also running TSLs there heavier then a dead priest but 35 is what the door says so i stay with that. seem to get the best mpg too

 

You went to bigger tires....90% of the time your gonna lose mpg's, 65psi unloaded will cause most tires to wear more in the center, I love the ride of tires around 35psi, but some tires cant wear right at that psi, somewhere around 45 to 55 seems to the lucky ticket as far as ride and wear pattern on D or E load range tires