235/45R17 vs 245/45R17Tire Size Comparison

Safe

The 1.4% diameter difference is within the accepted 3% tolerance.

235/45R17643mm dia245/45R17652mm dia+4.5mm

Comparison Details

Overall Diameter643.3 vs 652.3 mm (+9.0 mm)
Diameter Difference+1.40%
Section Width235 vs 245 mm (+10 mm)
Sidewall Height105.8 vs 110.3 mm (+4.5 mm)
Circumference2021.0 vs 2049.3 mm
Clearance Change+4.5 mm
Speedometer Error+1.40%
Revs/Mile796 vs 785

Speedometer Correction

When switching from 235/45R17 to 245/45R17, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h30.4 km/h+0.4 km/h
40 km/h40.6 km/h+0.6 km/h
50 km/h50.7 km/h+0.7 km/h
60 km/h60.8 km/h+0.8 km/h
70 km/h71.0 km/h+1.0 km/h
80 km/h81.1 km/h+1.1 km/h
90 km/h91.3 km/h+1.3 km/h
100 km/h101.4 km/h+1.4 km/h
110 km/h111.5 km/h+1.5 km/h
120 km/h121.7 km/h+1.7 km/h
130 km/h131.8 km/h+1.8 km/h

Individual Tire Size Details

235/45R17
Full specifications, compatible vehicles, and alternatives
245/45R17
Full specifications, compatible vehicles, and alternatives

Practical Guidance

Switching from 235/45R17 to 245/45R17 is within the industry-accepted 3% diameter tolerance. Your speedometer, ABS, and traction control should function normally. Both sizes fit the same 17-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 1.40%, width changes by 10mm.

Speedometer error will be 1.40%. At an indicated 100 km/h, actual speed is about 101.4 km/h.

Ground clearance changes by +4.5mm per side.