285/65R18 vs 275/70R18Tire Size Comparison

Safe

The 1.8% diameter difference is within the accepted 3% tolerance.

285/65R18828mm dia275/70R18842mm dia+7.3mm

Comparison Details

Overall Diameter827.7 vs 842.2 mm (+14.5 mm)
Diameter Difference+1.75%
Section Width285 vs 275 mm (-10 mm)
Sidewall Height185.3 vs 192.5 mm (+7.2 mm)
Circumference2600.3 vs 2645.8 mm
Clearance Change+7.3 mm
Speedometer Error+1.75%
Revs/Mile619 vs 608

Speedometer Correction

When switching from 285/65R18 to 275/70R18, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h30.5 km/h+0.5 km/h
40 km/h40.7 km/h+0.7 km/h
50 km/h50.9 km/h+0.9 km/h
60 km/h61.1 km/h+1.1 km/h
70 km/h71.2 km/h+1.2 km/h
80 km/h81.4 km/h+1.4 km/h
90 km/h91.6 km/h+1.6 km/h
100 km/h101.8 km/h+1.8 km/h
110 km/h111.9 km/h+1.9 km/h
120 km/h122.1 km/h+2.1 km/h
130 km/h132.3 km/h+2.3 km/h

Vehicles Using These Sizes

Vehicles with 285/65R18

2026 Toyota TundraTRD Pro hybrid (18")

Vehicles with 275/70R18

2026 Chevrolet SilveradoZR22026 Ford F-150Tremor

Individual Tire Size Details

285/65R18
Full specifications, compatible vehicles, and alternatives
275/70R18
Full specifications, compatible vehicles, and alternatives

Practical Guidance

Switching from 285/65R18 to 275/70R18 is within the industry-accepted 3% diameter tolerance. Your speedometer, ABS, and traction control should function normally. Both sizes fit the same 18-inch rim, so no wheel change is needed.

The 3% diameter tolerance is a widely accepted industry guideline referenced by the ETRTO and most vehicle manufacturers. When in doubt, consult your vehicle's owner's manual or a qualified tire professional. For U.S. tire safety standards and recalls, see the NHTSA Tire Safety page.

Frequently Asked Questions

Safe. The overall diameter differs by 1.75%, width changes by -10mm.

Speedometer error will be 1.75%. At an indicated 100 km/h, actual speed is about 101.8 km/h.

Ground clearance changes by +7.3mm per side.