Air Pressure vs Tire Size

Wednesday, May 5, 2010 by Porter Pryde
As many of us know, one of the easiest ways to improve the looks of your vehicle is to select a new tire and wheel package.  "Inching up" your wheel diameter provides a lower profile tire with a larger contact patch affording greater traction and steering response. But what about the tire air pressure?

One of the most common questions I hear is "what is the proper air pressure for my low profile tires?" 

Your vehicle manufacturer recommends an optimum tire pressure found in your owner's manual or a sticker in your door jamb or gas filler door. What is surprising is that even if the tire size changes, the recommended air pressure remains the same. In other words, the air volume from one tire size to another may be different but the recommended air pressure is unaffected.

Tire Rack makes it easy to monitor your air pressure by offering a variety of air gauges and tire pressure monitors. For the ultimate in convenience, check out the Psiclops XPRS. The XPRS allows you to preselect your air pressure and ensures even pressure from tire to tire.

Psiclops XPRS 

Psiclops XPRS

Comments on Air Pressure vs Tire Size

Wednesday, May 5, 2010 by Mike:
Some of the newer passenger tires (standard size/profile) have significantly higher maximum inflation pressures than their predecessors, 44psi in this case verses 32psi for earlier models. The plaquard on the B-Pillar states to use 30 psi. It seems that inflating to only 30psi vs 44psi could lead to an underinflated tire. Should I still follow the auto makers plaquard even though the newer tires have such a higher maxium inflation pressure? At what pressure would tires rated for maximum pressure of 32psi or 44psi be considered 'underinflated'? Thanks, Mike
Saturday, May 8, 2010 by porter:
Although tire manufacturers indicate a maximum air pressure for their tires, there is no guideline for minimum air pressure. As long as the vehicle manufacturers recomendation is followed pertaining to tire pressure, you are not harming the tire, even if the tire has been designed to provide additional load capacity. As a precaution, however, you would always want to observe the tire wear, monitoring for uneven wear indicating improper tire pressure. A well recognized sign of too low air pressure is tread wear down the center section of the tread.
Sunday, October 31, 2010 by Joe :
My car recommends 30 psi. I purchased the Yokohama Avid Envigor 225/50R16. Is the 30 psi ok for this tire or should it be something else?
Monday, November 1, 2010 by porter:
Follow the vehicle manufacturers recommendation for proper tire pressure The air volume from one tire size to another may be different but the recommended air pressure is unaffected.
Friday, March 11, 2011 by RON:
Friday, March 11, 2011 by porter:
The maximum air pressure for the tire is identified on the tire's side wall. That is the air pressure that should not be exceeded as determined by the tire manufacturer. However, the optimal air pressure for your vehicle is determined by the vehicle's manufacturer. By concidering various factors including the weight of the vehicle the recommended tire pressure will be less than the maximum air pressure stated on the tires side wall. You can find the recommended tire air presure for your vehicle by consulting the owners manual or finding the tire plaquard usually located in the doorsill of your vehicle.
Wednesday, March 23, 2011 by Steve:
Toyota recommends 32 PSI for the 17-inch tires on my '07 RAV4. Is this really the optimal pressure for tread wear and MPG? It seems low to me.
Thursday, March 24, 2011 by porter:
The manufacturer sets the recommended tire pressure for optimal performance of the vehicle and takes many factors into concideration. By over inflating your tires beyond the recommended pressure you risk unusual tread wear and shortening the service life of the tire. The manufacturer recommended tire pressure is your optimal pressure that allows your vehicle economical and safe operation.
Tuesday, November 8, 2011 by Rob :
I have 235/75/15 on my 1998 Chevy Blazer, What is the reccommended tire pressure.
Tuesday, April 10, 2012 by bryan:
i have an 09 ford explorer it had origionally 235/75/15 tires with a pressure of 30 suggested now i plus sized to a 265/40/22 lowprofile extra load tire every tire shop i call here in ohio says something diffrent for suggested pressure 30 seems real low i have 40 in them right now they are 49 max and seem to shake out like flat spotting every morning any suggestions ive herd 35-40 34 45 38. i even tried jacking truck up overnite to see if helpd flatspotting effect but nothing changed maybe front tires i only jacked up rears. center console shakes hard till tires warm up then fine.?

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