The 2014 GMC Sierra comes standard with P255/70R17 size tires on the truck. That number may look complexBut it is pretty easy to decipher when You know what each number means. The first number, 255, is the tire's tread width in millimeters. The second number, 70, is the tire's sidewall height in millimeters. The third number, 17, is the wheel diameter in inches. That means that Your truck comes standard witH17 inch wheels on it. GMC recommends that You inflate each tire on Your truck to 35psi. Keeping Your tires properly inflated helps with braking distance, and also helps Your tires last longer. Tires that are under or over inflated will wear unevenly and need to be replaced sooner.
I believe the second number, 70 is the percentage of the first number. So in this case, 255 ml wide, and 178.5 ml wide (70% of 255) on a 17 inch rim
Mara D.
January 2, 2020
The tire size for the 2014 GMC Sierra is Front Tire: P255/70R17 and Rear Tire P255/70R17. The recommended tire pressure for both front and rear tire is 35 psi. The standard wheel size is 17" silver aluminum wheels.
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