255/55R18 Tire Size Specifications & Compatible Vehicles
Overall Diameter
737.7 mm
Section Width
255 mm
Sidewall Height
140.3 mm
Circumference
2317.6 mm
Revs/Mile
694
Rim Diameter
18"
Inch Equivalent
29x10R18
Rim Width (ETRTO)
7.5" – 10.0"
Compatible Vehicles
The following vehicles use 255/55R18 tires from the factory:
Alternative Tire Sizes
These tire sizes are within 3% overall diameter of 255/55R18 and may be used as replacements:
Understanding 255/55R18
The tire size 255/55R18 means the tire has a section width of 255mm, an aspect ratio of 55% (the sidewall height is 55% of the width), and fits a 18-inch rim.
Sidewall Height = 255 x 0.55 = 140.3 mm
Overall Diameter = (140.3 x 2) + (18 x 25.4) = 737.7 mm
Circumference = 737.7 x π = 2317.6 mm
Overall Diameter = (140.3 x 2) + (18 x 25.4) = 737.7 mm
Circumference = 737.7 x π = 2317.6 mm
Frequently Asked Questions
The 255/55R18 tire size is used on 4 vehicle trims including the 2025 Infiniti QX60, 2024 Infiniti QX60, 2023 Infiniti QX60 and 1 more.
A 255/55R18 tire has an overall diameter of 737.7mm (29.0 inches). The sidewall height is 140.3mm, and the total circumference is 2318mm.
For 255/55R18 tires, the ETRTO recommended rim width is 8.5". The acceptable range is 7.5" minimum to 10.0" maximum. Using a rim outside this range can cause improper bead seating and unsafe handling.
Yes, as long as the replacement tire overall diameter is within 3% of the 255/55R18 737.7mm diameter. Compatible alternatives include 165/85R18, 255/60R17, 255/50R19. Use our Tire Size Calculator to compare any two sizes.