315/70R18 tire size

A 315/70R18 tire is 35.36 in (898.2 mm) tall and 12.40 in (315.0 mm) wide, and turns 570 revolutions per mile.

• 35.36 inOverall diameter
• 8.68 inSidewall height
• 570Revolutions per mile
• 35.4x12.4R18Flotation equivalent

315/70R18 is a 18-inch tire with a 315 mm (12.40 in) section width and a 70% aspect ratio, giving a 8.68-inch sidewall and a flotation-style size of about 35.4x12.4R18.

Its overall diameter is 35.36 inches, so it rolls 111.1 inches per revolution and turns about 570 times per mile.

16 other sizes in this list are within 3% of that diameter.

Compare 315/70R18 with plausible swaps

• 315/75R16 vs 315/70R18 (−2.15%)
• 315/70R17 vs 315/70R18 (−2.83%)
• 35x11.50R17 vs 315/70R18 (−1.02%)
• 35x12.50R17 vs 315/70R18 (−1.02%)
• 315/75R17 vs 315/70R18 (+0.68%)
• 37x12.50R17 vs 315/70R18 (+4.63%)
• 37x13.50R17 vs 315/70R18 (+4.63%)
• 295/70R18 vs 315/70R18 (−3.12%)
• 305/70R18 vs 315/70R18 (−1.56%)
• 285/75R18 vs 315/70R18 (−1.50%)
• 35x12.50R18 vs 315/70R18 (−1.02%)
• 315/70R18 vs 37x12.50R18 (+4.63%)
• 315/70R18 vs 37x13.50R18 (+4.63%)
• 315/70R18 vs 275/65R20 (−3.64%)
• 315/70R18 vs 315/60R20 (−1.36%)
• 315/70R18 vs 35x12.50R20 (−1.02%)
• 315/70R18 vs 35x13.50R20 (−1.02%)
• 315/70R18 vs 325/60R20 (−0.02%)
• 315/70R18 vs 37x12.50R20 (+4.63%)
• 315/70R18 vs 37x13.50R20 (+4.63%)

Sizes within 3% of 35.36 in diameter

• 325/60R20 35.35 in (−0.02%)
• 315/75R17 35.60 in (+0.68%)
• 35x12.50R15 35.00 in (−1.02%)
• 35x12.50R17 35.00 in (−1.02%)
• 35x12.50R18 35.00 in (−1.02%)
• 35x12.50R20 35.00 in (−1.02%)
• 35x13.50R20 35.00 in (−1.02%)
• 35x12.50R22 35.00 in (−1.02%)
• 35x11.50R17 35.00 in (−1.02%)
• 35x12.50R24 35.00 in (−1.02%)
• 315/60R20 34.88 in (−1.36%)
• 285/75R18 34.83 in (−1.50%)
• 305/70R18 34.81 in (−1.56%)
• 325/50R22 34.80 in (−1.60%)
• 315/75R16 34.60 in (−2.15%)
• 315/70R17 34.36 in (−2.83%)

Open 315/70R18 in the tire size calculator

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.