Tire Pressure and Low Profile Tires?

[BimmerM3]

So I was talking to someone at work today with a 2007 IS350. He said a low pressure light came on, so he checked his pressure, and it was 26psi, which is, admittedly, pretty low. So he checks his sticker, and notices that the recommended pressure is 35 up front and 37 in the rear. I'm not doubting Lexus's recommendation, but it seemed awfully high. Is it normal for low profile tires to have such high tire pressure, or is it just his car?

[Pancor]

Normal.

[The Pirate]

My car recommends 34 psi.

[BimmerM3]

My car recommends 34 psi.

What profiles are your tires?

[The Pirate]

What profiles are your tires?

195/50/16

It's an odd size (factory though), and I'm going to go up to a 205 with a shorter aspect ratio next time.

[JYODER240]

normal, I run 35(cold) all around for normal driving.

[Champ]

I run 35-40 (usually 40) in my low profiles.  Saves on the cost of rim repair.

[TheIntrepid]

Ehh..I'm too lazy to fill up my air so I'm usually running 28-29 on my fronts and 34-35 on my rears.

[MX793]

I run 34-35 psi in my tires, which are relatively low profile.  IIRC, the sticker in the glove box recommends 33.  I ran 34-ish psi in my last car, which did not have low profile tires.

[565]

Apparently my car came with 20psi all around when I got it from the dealer, which was probably dangerously low, but I didn't notice for a good 4 months  .

The recommended PSI is 30PSI all around, when I inflated my tires to the proper PSI, the only real difference I noticed was a stiffer ride.  I'm surprised it is that high for other low profile tires.

[Raghavan]

That seems normal...
You'd want the PSI to be higher for a stiffer sidewall so you don't go bending your wheels over every bump and pothole.

[BimmerM3]

Thanks for the replies. My car recommends 29s all around and his previous car was 30 I think, so it seemed odd to us.

[MX793]

Something else to watch out for is tire wear.  In ordinary driving, the tread should wear evenly across the tire.  When you check your tread depth, you should check it across the width of the tire.  If you find that the center of the tire has less tread than the shoulders, then you are running too much air pressure.  If the shoulders are wearing faster than the center, then you are running too little pressure.

[BartsSVO]

I usually run about 40 psi all the way around. Once you get below a 50 series tire, the difference in ride quality and tire wear is minimal because the sidewall is so inflexible anyway. If a car specifies a pressure in the low 30s, it is primarily about ride quality, not performance or tire wear.

[Lebowski]

The recommended PSI is 30PSI all around, when I inflated my tires to the proper PSI, the only real difference I noticed was a stiffer ride.  I'm surprised it is that high for other low profile tires.

Me too, mine is 30psi all around and I thought that was pretty normal for low profile tires.

[FordSVT]

Ehh..I'm too lazy to fill up my air so I'm usually running 28-29 on my fronts and 34-35 on my rears.

I don't suppose we need to get into why that's a stupid thing to do, eh? It takes, what.... 1-5 minutes ever two weeks of your life?

I've got 215/50-17s on my car and the spec is for 32 lbs all around which is what I keep them at.

[The Pirate]

Err, I happened to check my doorjamb today, and my car calls for 32 psi as well.  I run 35 psi though.  No odd tire wear thus far.

[Lazerous]

My car does 30 all around. I got some nifty little tire pressure monitors on there too, so I know that they are always on 30 :)