225/35R18 Tire Size Specifications & Compatible Vehicles

Overall Diameter

614.7 mm

Section Width

225 mm

Sidewall Height

78.8 mm

Circumference

1931.1 mm

Revs/Mile

833

Rim Diameter

18"

Alternative Tire Sizes

These tire sizes are within 3% overall diameter of 225/35R18 and may be used as replacements:

225/40R17 Safe 0.5% · same width · -1" rim 235/45R16 Safe 0.5% · +10mm · -2" rim 205/50R16 Safe 0.5% · -20mm · -2" rim 235/40R17 Safe 0.8% · +10mm · -1" rim 225/45R16 Safe 0.9% · same width · -2" rim 215/50R16 Safe 1.1% · -10mm · -2" rim 235/35R18 Safe 1.1% · +10mm · same rim 215/45R17 Caution 1.7% · -10mm · -1" rim 215/40R17 Caution 1.8% · -10mm · -1" rim 245/35R17 Caution 1.9% · +20mm · -1" rim 245/40R17 Caution 2.1% · +20mm · -1" rim 245/35R18 Caution 2.3% · +20mm · same rim

Understanding 225/35R18

The tire size 225/35R18 means the tire has a section width of 225mm, an aspect ratio of 35% (the sidewall height is 35% of the width), and fits a 18-inch rim.

Sidewall Height = 225 x 0.35 = 78.8 mm
Overall Diameter = (78.8 x 2) + (18 x 25.4) = 614.7 mm
Circumference = 614.7 x π = 1931.1 mm

With an aspect ratio of 35%, this is a low-profile tire. Low-profile tires offer sharper steering response and better cornering stability, but provide a firmer ride and are more susceptible to pothole damage. They are commonly found on sport sedans and performance vehicles.

Choosing Replacement Tires

When replacing 225/35R18 tires, verify the size matches your vehicle's tire placard (typically found on the driver's door jamb or in the owner's manual). The NHTSA Tire Ratings Search tool lets you look up manufacturer load and speed ratings for specific tires.

Key factors beyond size: load index (must meet or exceed the vehicle's requirement), speed rating (must match or exceed the original specification), and seasonal type (all-season, summer, or winter) based on your driving conditions. The U.S. Tire Manufacturers Association recommends replacing all four tires at once, or at minimum in pairs on the same axle.