175/65R14 vs 185/65R15Tire Size Comparison

Not Recommended

The 6.6% diameter difference exceeds 5% and could affect ABS and traction control.

175/65R14583mm dia185/65R15622mm dia+19.2mm

Comparison Details

Overall Diameter583.1 vs 621.5 mm (+38.4 mm)
Diameter Difference+6.59%
Section Width175 vs 185 mm (+10 mm)
Sidewall Height113.8 vs 120.3 mm (+6.5 mm)
Circumference1831.9 vs 1952.5 mm
Clearance Change+19.2 mm
Speedometer Error+6.59%
Revs/Mile879 vs 824

Speedometer Correction

When switching from 175/65R14 to 185/65R15, your speedometer will differ from actual speed.

SpeedometerActual SpeedDifference
30 km/h32.0 km/h+2.0 km/h
40 km/h42.6 km/h+2.6 km/h
50 km/h53.3 km/h+3.3 km/h
60 km/h64.0 km/h+4.0 km/h
70 km/h74.6 km/h+4.6 km/h
80 km/h85.3 km/h+5.3 km/h
90 km/h95.9 km/h+5.9 km/h
100 km/h106.6 km/h+6.6 km/h
110 km/h117.2 km/h+7.2 km/h
120 km/h127.9 km/h+7.9 km/h
130 km/h138.6 km/h+8.6 km/h

Vehicles Using These Sizes

Vehicles with 175/65R14

Individual Tire Size Details

Practical Guidance

A 6.6% diameter difference is significantly outside the safe replacement range. Switching from 175/65R14 to 185/65R15 can cause dangerous speedometer inaccuracy, ABS/traction control malfunctions, and potential clearance issues. This change is not recommended without professional verification and possible ECU recalibration.

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

Not Recommended. The overall diameter differs by 6.59%, width changes by 10mm.

Speedometer error will be 6.59%. At an indicated 100 km/h, actual speed is about 106.6 km/h.

Ground clearance changes by +19.2mm per side.