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Super Moderator
Joined: Apr 2004
Posts: 34,512
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Sounds like you went from a P (passenger car) tire with your 265s to a LT (light truck) tire with the 285s.
Read the sidewalls and compare.
You can run your 285s at 70. They require 80 for the maximum load printed on the sidewall.
Same with your old tires--44 was max load, you vehicle probably spec'd 35 or 40.
Read the sidewalls and compare.
You can run your 285s at 70. They require 80 for the maximum load printed on the sidewall.
Same with your old tires--44 was max load, you vehicle probably spec'd 35 or 40.
Fleet Mechanic
Joined: Jul 2010
Posts: 1,753
Likes: 34
From: Los Angeles, Ca.
At 70psi you're probably still well over what you need. You ever notice how many pickup tires wear in the center of the tread? That's because they have too much air. Air down 'till you have good contact all the way across the tread. You'll likely find that it rides and handles better. If those tires are too wide for your wheels you may find that to get perfect complete contact you have to air down too far and your handling starts to degrade, at that point find a happy medium of pressure where your handling is good.
I generally won't use the max pressure unless I'm loaded heavy. All my vehicles get the amount of air they need to achieve the best tread contact. In some cases I've had to tweak it further to achieve the best ride/handling, but usually not. The manufacturer's suggested air pressure is for the factory tires and at maximum load. Generally speaking, the bigger the tire and the lighter the load, the less air you need. I run around 30 psi in my F-350 CC 4x4, it has 37" tires. At the tire's max of 50psi the ride will rattle your teeth loose and the tires would wear out in the middle because the edges won't touch the ground. When I put my extremely heavy boat trailer on I air up the rears to about 45.
I generally won't use the max pressure unless I'm loaded heavy. All my vehicles get the amount of air they need to achieve the best tread contact. In some cases I've had to tweak it further to achieve the best ride/handling, but usually not. The manufacturer's suggested air pressure is for the factory tires and at maximum load. Generally speaking, the bigger the tire and the lighter the load, the less air you need. I run around 30 psi in my F-350 CC 4x4, it has 37" tires. At the tire's max of 50psi the ride will rattle your teeth loose and the tires would wear out in the middle because the edges won't touch the ground. When I put my extremely heavy boat trailer on I air up the rears to about 45.
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