Took my 2011 GT in for routine maintenance. I noticed that the dealership inflated my OEM tires to 35lbs vs. the manufacturer's recommended 32lbs. They even wrote "35lbs" in the paperwork. The ride is a bit stiffer and road noise is a bit louder. Any idea why they would choose 35lbs over 32lbs? Thanks.

 

I keep 42psi in mine. Been my experience over the years that I get a LOT more mileage (life) from tires with higher pressure. Only time I notice any difference in 'feel' is when I can't get around a speed hump in parking lots.

 

and better handling... 40 in mine too

 

Whoa...I'm inexperienced, but 40-42 definitely sounds like the wheels are rock hard (I'm thinking Fred Flintsone)...I can see the slight increase in mileage...but what about wear? Wouldn't the middle of the tire wear out faster than the outer parts?

 

My door jamb says 35 psi for my tires?

 

40+ is a bit extreme as they are so hard that handling corners is not as easy as when down around the 32 mark. I can tell a huge difference at road course events when the tires get hot and overinflated.

 

Whao is right, some bad info here.

Over inflating your tires gives you LESS traction, wet or icy roads will make it even worse! It also makes the ride rougher and increases vibration. It will also increase your chance for a blow out and increase the chance to damage your tire on a pot hole, curb, etc.

Like Magnido45 siad, it will cause the center of your tires to wear out faster. The faster wear will negate any extra gas mileage(which is almost 0), not to mention the dangers.

Whie 40 PSI is not extremely dangerous, keep it around 32 PSI.

 

Yeah, 40psi is a little extreme. They don't put the recommended pressures on the door label just to take up space.

 

I keep 32-25 psi in my tires. Anything over that makes the middle wear out faster.

 

I agree with Joe, Planeswalkerand Timless. Over inflated tires makes the center wear out. There is no way tires gonna last longer that way. Flat all the way across the contact patch is the only way tire is gonna last longer. I run 30lbs and my tires are wearing great.

 

32. Anything more feels like I'm on ice, wandering about. Nasty.

 

I deflated my tires to 33lbs for now...at 35lbs, it's not a comfortable ride for me...

 

If you running 42 on a good hot day you're probably around 45+

 

I went up just 1# to 33 (cold) to experiment and I could feel a bit more slide on my favorite 2 lane twisty that I know well. I was surprised. It never broke free or anything but I could tell. Actually I liked it with the B's balance.
But I don't think I'd want to go to 35#.

 

Tires have two published values. Max load and Max tire pressure. Use max presure at max load. For lesser loads reduce pressure accordingly.

 

Get a tread depth gauge. Check you tires in 3 spots regularly. I ran my stock tire at 35 all the time.

 

27 lbs in rear helped my traction issues immensely.

 

If anyone remembers the Explorer that Ford had 25PSI on think about what the pressure is on the side wall and not the door jam. I ran 37 Front and 34 Rear in my Mazda 3, played around with it till I found a pressure that handled good.
I am at 41 Front and 40 rear right now on the Mustang, at 35 the car felt like a boat in corners and the front looked low. Ran my Stock Perellis at 32 to 35 and the outsides of the tires were starting to show wear and cupping at less than 20000 miles. Ran the pressure up and replaced them at 36000 miles

 

Probably just misguided practical experiece. Alot of people dont realize that the inflation pressure listed on the decal is a cold inflation pressure, when you drive someplace the tire heats up obviously and if you adjust the hot tire to the pressure on the decal it will be under inflated.

The Rubber Manufacturers Association reccomends adding 4 psi to the cold inflation pressure if you drive more than a mile before checking the air pressure and then checking the pressure again after the vehicle has sat for 8 or more hours and then adjust accordingly.

In my expereice, adding 2-3 psi to the cold inflation pressure does the trick in most cases when a tire hasn't been driven extensively or in extreme weather.

Also on the matter of increased air pressure, the contact patch on your tire is dicated by the vehicle weight and air pressure. Increasing the air pressure will decrease the contact patch relative to the load imposed on the tire and in an odd twist of fate with a radial tire at least, in the rain, running a low tire pressure (as low as 3-4 psi) will allow the tire to deform when traveling through standing water reducing the contact patch as well.

 

Dont adjust the air pressure in a radial tire until it "looks right", I've seen people unwittingly increase the pressure to as much as 80 psi in the absence of a tire pressure gauge and feeling comfortable with the appearence of the tire and predictably suffering catastrophic results when they hit some pocked asphalt or concrete or a hard bump in the road.

Radial tires naturally bulge when a load is placed on them often leading people to beleive they are under inflated when nothing is farther from the truth.