Changing Wheel and Tire Sizes, What Pressure Should I Run?

If you're going from 17" Original Equipment wheels to 18" aftermarket wheels, what tire pressure should you run with your new tires? Many times, the service description (e.g. 98H) is still the same on the tires when the size is adjusted, so the same pressure can be used. If the load index is higher on the new tires, then you still follow your vehicle's door placard specifications. If the load index is lower than the O.E. tire, you will want a slightly higher tire pressure. How much higher sometimes varies, so contact us to verify. However, if the tire size is a good fit for the vehicle, you're typically safe using the following pressures (all options will carry the max load listed on the tire):

  • 35 PSI for standard load tires with the "P" in front of the size (P-metric tires), e.g. P205/55R16 89T
  • 36 PSI for standard load tires without the "P" in front of the size (euro-metric tires), e.g. 205/55R16 91H
  • 41 PSI for extra load (XL) tires with the "P" in front of the size (P-metric tires), e.g. P205/55R16 92T
  • 42 PSI for extra load (XL) tires without the "P" in front of the size (euro-metric tires), e.g. 205/55R16 94H

If the service description on your new tires is higher than your stock tires, you're fine running the tire pressure listed on your vehicle's placard. 

For LT-metric tires, use the following list:

  • Load Range C (LRC) - 50 psi (350 kPa)*
  • Load Range D (LRD) - 65 psi (450 kPa)*
  • Load Range E (LRE) - 80 psi (550 kPa)*
  • Load Range F (LRF) - 95 psi (650 kPa)*

*Industry standards specify selected large LT tire sizes be designed with reduced maximum load pressures

To learn more about your tires' air pressure, take a look at "Checking Tire Inflation Pressure."

Comments

Thursday, April 2, 2015 by Ashlie Taylor

My cars original OE tires were P205/55R16 and I recently put 225/40ZR18 XL load tires on it. What is the recommended psi?
Friday, April 3, 2015 by Turk

What was the service description on your old tires, and what is the service description on your new tires? If the new tires have the same or higher number than your old ones, then the same pressure is used. If you need help, email me at turk@tirerack.com and I can go over the pressures with you!

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