265/65R18 vs 255/70R17 tire size comparison

Change either size and everything below updates.

Start from your car make, model, year

Make Model Year

Width/AspectRRim

DiameterxWidthRRim

Width/AspectRRim

DiameterxWidthRRim

Width in mm · aspect = sidewall height as a % of width · rim in inches

Flotation (LT) sizes, all in inches: overall diameter × section width, then rim

Within the usual 3% rule

−1.61% diameter

Most fitment guides accept up to 3%. Check clearance at full lock and full suspension compression before committing.

Needs 17″ wheels: this tire does not fit your 18″ rims.
10 mm narrower: check the tire is approved for your rim width.

Tires in 255/70R17

Check price on Amazon · 255/70R17 Best-rated 255/70R17 tires

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Measurement	265/65R18	255/70R17	Diff	%
Overall diameter	31.56″802 mm	31.06″789 mm	−0.51″	−1.6%
Section width	265.0 mm	255.0 mm	−10.0 mm	−3.8%
Sidewall height	172.3 mm	178.5 mm	+6.3 mm	+3.6%
Rim diameter	18″	17″	−1″	−5.6%
Circumference	99.16″2519 mm	97.56″2478 mm	−1.60″	−1.6%
Revolutions per mileturns per distance; drives the odometer	639397 /km	649404 /km	+10	+1.6%
Ride height change	—	—	−0.25″ −6.4 mm

Speedometer reading

Speedo shows

60mph

97 km/h

Actual speed

59.0mph

95 km/h

Overlay

265/65R18255/70R17

How to use the tire size calculator

Put your current tire size — width, aspect ratio and rim diameter — into the first form, then your desired size into the second. You’ll get the difference between the new and the old size, plus the speedometer reading difference and your actual speed on the new set. Both metric and flotation (LT inch) sizes are supported.

The calculator helps you decide whether a set of tires and wheels will fit your car. To compare tires by brand and model instead, use our tire comparison tool; to look up factory sizes, browse by car make.