275/45R18 Tire Size Specifications & Compatible Vehicles
Overall Diameter
704.7 mm
Section Width
275 mm
Sidewall Height
123.8 mm
Circumference
2213.9 mm
Revs/Mile
727
Rim Diameter
18"
Inch Equivalent
27.7x10.8R18
Rim Width (ETRTO)
8.5" – 11.0"
Alternative Tire Sizes
These tire sizes are within 3% overall diameter of 275/45R18 and may be used as replacements:
Understanding 275/45R18
The tire size 275/45R18 means the tire has a section width of 275mm, an aspect ratio of 45% (the sidewall height is 45% of the width), and fits a 18-inch rim.
Sidewall Height = 275 x 0.45 = 123.8 mm
Overall Diameter = (123.8 x 2) + (18 x 25.4) = 704.7 mm
Circumference = 704.7 x π = 2213.9 mm
Overall Diameter = (123.8 x 2) + (18 x 25.4) = 704.7 mm
Circumference = 704.7 x π = 2213.9 mm
Frequently Asked Questions
The 275/45R18 is a standard tire size. Check your vehicle door jamb sticker or owner manual to confirm compatibility.
A 275/45R18 tire has an overall diameter of 704.7mm (27.7 inches). The sidewall height is 123.8mm, and the total circumference is 2214mm.
For 275/45R18 tires, the ETRTO recommended rim width is 9.5". The acceptable range is 8.5" minimum to 11.0" 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 275/45R18 704.7mm diameter. Compatible alternatives include 165/75R18, 225/55R18, 195/70R17. Use our Tire Size Calculator to compare any two sizes.