I recently realized that the dealer had set my tire pressure for my OEM 19's at 42+psi on all tires. I have been driving with those settings for the past 2+ months and really had no problems. I recently set the tire pressure to the reccomended setting of 35psi and noticed that the ride is a little bit smoother although I feel like I may have lost some traction to the road. What is the purpose of having a higher tire pressure? Does this increase handling but warp tire wear? Are there any advantages of having higher psi? What are the main disadvantages?

 

great question. I'd like to learn about this too.

 

Most people do not check their tire presssures so dealers tend to
pressure up the tires (especially through winter seasons) much higher than
recommended to last the 3months or so interval until the next oil change.

My dealer does that too...so i always tell them not to touch
my tires.

High tirepressure at lower speeds for auto-x, etc has better turn-in response
but typically tires do not respond well to street driving especially in the 40+psi
range. I would use 36-37psi on 19" tires when ambient temps are 65F and above.

 

Higher pressures make a tire harder and less likely to deform under stress like cornering, braking, accelerating. So cornering will be sharper, rolling resistance will be less so you'll get better gas mileage, but you will feel the road surface even more which makes it more uncomfortable.

Lower pressures are just the opposite. However, too low will cause the tire to overheat and more likely to fail while driving.

I always set it to manufacturer's specs and maybe a couple of psi higher than recommended. Seems to be a good balance.

 

The AREA of the tire contact patch is controlled by PSI.........say 900 pounds on a tire [including tire/wheel]/42 psi= 21.428 square inches.........900/35=25.7 sq. inches.

POUNDS PER SQUARE INCH.........35 psi is the usually test pressure in labs to determine tire parameters.

 

Higher tire pressure equates to faster tire wear, the centers will be bald and you'll have very little wear on the edges along with a very sh!tty ride. If the center of your tires are wearing faster you will have a smaller amount of rubber rolling down the street....logic? Just another reason NOT to take your car to the stealership!
Gary

 

Typically the higher pressure will help steering response and reduce roll over in corners. May also decrease ride and if inflated too much can cause irregular tire wear down the center.

 

+1 Saw this happen to a friend