Don't the tires themselves have the proper rating on them? I can't remember. It's been a while since I've actually gotten down there and looked at my tires. Since July actually ... when one of them actually went flat. Stupid shard of metal.
I haven't looked at mine, but in many cases it's the "maximum" psi that's listed on the tire, not the "recommended" psi.
I voted for plural, "tires". No plans here to trade my Acadia in for a unicycle. ;D
PS I also got a report the other day from Onstar that my tires were low. Four tires - four different numbers. I got out my trusty old tire pressure gauge and checked. Onstar's numbers were spot on for all four.
The last report I got from OnStar indicated that I had no pressure in my tires at all. But did happen to be the day that my Acadia was at the dealership for an oil change and tire rotation. So I figured that must have had something to do with it since my tires all had air in them when I picked it up from the dealer.
I'm for recommendation of 34-37 lbs summer and 40-43 lbs snow season. You ask me why more in the snow season? Spreads out the tire tread for more snow bite. Do the same when put 4 Blizzak's on my Stang...40-43lbs. I only go by what my mechanical tire gauge reads every two weeks. I'm sure happy we still have a gas station in town that has FREE air, which is only 10 minutes from home. I overfill that evening and then let the right amount of air out in the morning. Now that is some kind of schedule, wouldn't you say??? :dancing:
I go by the chart/label on the driver side door jamb. It is usually a "happy" median between ride comfort and gas economy. On my Outlook, the 19's require 35 psi. I usually add .5 to 1 psi more. First thing in the morning is a great time to check tire pressure.
Adding too much air pressure will cause the center of the tread to wear prematurely. It will also reduce the amount of tread touching the road thereby giving a little better gas mileage. A trade off though.
Having too little air in the tires will cause the exterior sections of the tread to wear prematurely and raise the chance for a blowout. Although, driving in the sand is improved by reducing the amount of air in the tires. Some people forget to re-inflate their tires and end up with horrible handling and/or a flat down the road.
I pretty much leave my tires alone unless OnStar or the DIC informs me that something is wrong with them. I have them rotated every other oil change, and I glance at them when I fill up the tank to make sure they're not looking flat. But other than that, I depend on computers to keep me informed.