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285/70R17 vs 315/70R17

The 315/70R17 is 34.36 in tall: 1.65 in (5.1%) taller than the 285/70R17 at 32.71 in. At an indicated 60 mph you'd be doing 63.0 mph.The 315/70R17 is 872.8 mm tall: 42.0 mm (5.1%) taller than the 285/70R17 at 830.8 mm. At an indicated 100 km/h you'd be doing 105.1 km/h.

By David Owen. Published 3 November 2026.

in, mphmm, km/h

Each figure is rounded separately, so related figures can differ in the last digit.

These are size-code figures only. Whether a size fits, clears and carries your load depends on your vehicle and the tire, so check with a tire shop.

What changes

Only the section width changes, from 11.22 in to 12.40 in. The aspect ratio is a percentage of the width, so each sidewall grows with it, by 0.83 in, and the 315/70R17 ends up 1.65 in taller overall.

Makers' own measured diameters run 32.76 to 33.15 in for the 285/70R17 and 34.4 to 34.65 in for the 315/70R17, against the calculated 32.71 in and 34.36 in. Real tires vary by brand and tread design; the figures in the table come from the size code alone.

Speedometer and odometer

A speedometer that read true on the 285/70R17 reads low on the 315/70R17: an indicated 60 mph is a true 63.0 mph.A speedometer that read true on the 285/70R17 reads low on the 315/70R17: an indicated 100 km/h is a true 105.1 km/h.

The odometer records about 9,520 miles for every 10,000 you drive.The odometer records about 9,520 km for every 10,000 you drive.

Ground clearance and size class

Ground clearance at the axle rises by 0.83 in: half the diameter change, unloaded.Ground clearance at the axle rises by 21.0 mm: half the diameter change, unloaded. By calculated diameter the 285/70R17 is a 33-inch tire and the 315/70R17 a 34-inch tire.

See every 33-inch and 34-inch size in metric.

Other comparisons with these sizes

• 265/70R17 vs 285/70R17
• 285/70R17 vs 285/75R17
• 285/70R17 vs 33x12.50R17
• 315/70R17 vs 35x12.50R17

285/70R17 in inches.

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