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315/70 R18 Tires

Everything we know about the 315/70 R18 tire size: 1 owner reviews covering 24,500 miles of driving, and EU label data for the tires you can actually buy in it.

  • 1owner reviews
  • 24,500 milescovered on them
315/70 R18 To scale, mm
Ø 898 315 221 18" 221

What does 315/70 R18 mean?

A 315/70 R18 tire is 315 mm wide, its sidewall is 70% of that width (221 mm) tall, and it fits a 18 inch wheel. That gives an overall diameter of roughly 898 mm.

Section width315 mm
Sidewall height221 mm
Rim diameter18" (457 mm)
Overall diameter≈ 898 mm
Circumference≈ 2,822 mm
Revolutions per km≈ 354
Revolutions per mile≈ 570

Also written as

315/70R18 315/70 ZR18 315-70-18 315 70 18

Figures are calculated from the nominal size. A loaded, rolling tire runs a few percent smaller, and true widths vary slightly between makes.

Comparing two sizes? Use the tire size calculator →

What cars use 315/70 R18 tires?

The cars most often running this size in our owner reviews. Each links to the best rated tires for that exact car.

Dodge Ram 2500 1 reviews in this size

What drivers say about their 315/70 R18 tires

The most recent owner reviews fitted in this size, in their own words.

57%
Cooper Discoverer AT3 315/70 R18 Dodge Ram 2500 24,500 miles June 6, 2025
Purchase because of the 60k treadwear warranty.
Tires were TOAST after 24,500 miles and I am a passive driver.
Dealer said I would likely get NOTHING out of Cooper. After pressure, he sent in the treadwear and rotation information but the only way they would even consider it was if I SENT IN THE TIRES. How do you send in the tires??? What do I drive while they are deliberating? Only option was to by a (too expensive) set of tires to drive while Cooper decides my fate.
VERY DISAPPOINTED to say the least. Never again.

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Where this data comes from

Owner ratings are submitted through the review form on this site, naming the tire, the size and the distance covered, and are checked by hand before publication. Test results come from independent published tire tests indexed by size, and label values from the EU EPREL database.

About the TR Score

The Tire Reviews Score rates each tire out of 10 using independent test results and the full body of owner reviews, so you can check a car-specific ranking against the wider evidence.

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Who does the testing

Every test published as a Tire Reviews test is run by Jonathan Benson, who has been testing tires independently since 2007.

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