235/55R19 vs 255/45R19Tire Size Comparison

Use Caution

The 3.9% diameter difference exceeds 3% and may affect speedometer accuracy.

235/55R19741mm dia255/45R19712mm dia-14.5mm

Comparison Details

Overall Diameter741.1 vs 712.1 mm (-29.0 mm)
Diameter Difference-3.91%
Section Width235 vs 255 mm (+20 mm)
Sidewall Height129.3 vs 114.8 mm (-14.5 mm)
Circumference2328.2 vs 2237.1 mm
Clearance Change-14.5 mm
Speedometer Error-3.91%
Revs/Mile691 vs 719

Speedometer Correction

When switching from 235/55R19 to 255/45R19, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h28.8 km/h-1.2 km/h
40 km/h38.4 km/h-1.6 km/h
50 km/h48.0 km/h-2.0 km/h
60 km/h57.7 km/h-2.3 km/h
70 km/h67.3 km/h-2.7 km/h
80 km/h76.9 km/h-3.1 km/h
90 km/h86.5 km/h-3.5 km/h
100 km/h96.1 km/h-3.9 km/h
110 km/h105.7 km/h-4.3 km/h
120 km/h115.3 km/h-4.7 km/h
130 km/h124.9 km/h-5.1 km/h

Vehicles Using These Sizes

Vehicles with 235/55R19

Vehicles with 255/45R19

Individual Tire Size Details

Practical Guidance

The 3.9% diameter difference between 235/55R19 and 255/45R19 exceeds the standard 3% tolerance. While physically possible, this change will cause noticeable speedometer error and may affect ABS and traction control calibration. Consult a tire professional before making this switch.

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

Use Caution. The overall diameter differs by -3.91%, width changes by 20mm.

Speedometer error will be -3.91%. At an indicated 100 km/h, actual speed is about 96.1 km/h.

Ground clearance changes by -14.5mm per side.