245/35R20 vs 255/35R20Tire Size Comparison

Safe

The 1.0% diameter difference is within the accepted 3% tolerance.

245/35R20680mm dia255/35R20687mm dia+3.5mm

Comparison Details

Overall Diameter679.5 vs 686.5 mm (+7.0 mm)
Diameter Difference+1.03%
Section Width245 vs 255 mm (+10 mm)
Sidewall Height85.8 vs 89.3 mm (+3.5 mm)
Circumference2134.7 vs 2156.7 mm
Clearance Change+3.5 mm
Speedometer Error+1.03%
Revs/Mile754 vs 746

Speedometer Correction

When switching from 245/35R20 to 255/35R20, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h30.3 km/h+0.3 km/h
40 km/h40.4 km/h+0.4 km/h
50 km/h50.5 km/h+0.5 km/h
60 km/h60.6 km/h+0.6 km/h
70 km/h70.7 km/h+0.7 km/h
80 km/h80.8 km/h+0.8 km/h
90 km/h90.9 km/h+0.9 km/h
100 km/h101.0 km/h+1.0 km/h
110 km/h111.1 km/h+1.1 km/h
120 km/h121.2 km/h+1.2 km/h
130 km/h131.3 km/h+1.3 km/h

Vehicles Using These Sizes

Vehicles with 255/35R20

2025 Acura TLXType S2024 Acura TLXType S2023 Acura TLXType S2022 Acura TLXType S

Individual Tire Size Details

245/35R20
Full specifications, compatible vehicles, and alternatives
255/35R20
Full specifications, compatible vehicles, and alternatives

Practical Guidance

Switching from 245/35R20 to 255/35R20 is within the industry-accepted 3% diameter tolerance. Your speedometer, ABS, and traction control should function normally. Both sizes fit the same 20-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 1.03%, width changes by 10mm.

Speedometer error will be 1.03%. At an indicated 100 km/h, actual speed is about 101.0 km/h.

Ground clearance changes by +3.5mm per side.