CarSpecsHQ

185/60R15 vs 185/65R15

185/65R15 is outside the ±3% rule as a replacement for 185/60R15: the diameter differs by +3.07%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

15" rim
185/60R15 23.74" · 185/65R15 24.47" · drawn to scale

Side by side

185/60R15185/65R15Difference
Overall diameter23.74"24.47"+0.73" (+3.07%)
Section width185 mm185 mm0 mm
Sidewall4.37"4.73"+0.36"
Rim15"15"same
Circumference74.6"76.9"+2.3"
Revs per mile850824-25
Ride height——+0.36"
Speedometer reads 60 mph60.061.8+1.8 mph

Speedometer and odometer

020406080100120 reads 60 · actual 61.8 mph

With 185/65R15 on a car calibrated for 185/60R15, the speedometer reads 58.2 mph when you're really doing 60, and the odometer under-counts by 3.1%.

Speedo showsActual speed
30 mph30.9 mph
45 mph46.4 mph
60 mph61.8 mph
70 mph72.1 mph
80 mph82.5 mph

Other sizes close to 185/60R15

Questions

Can I replace 185/60R15 with 185/65R15?

185/65R15 is outside the ±3% rule as a replacement for 185/60R15: the diameter differs by +3.07%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.

What's the difference between 185/60R15 and 185/65R15?

185/65R15 is 0.73" taller and 0 mm wider; the sidewall is +0.36". At an indicated 60 mph you'd actually be doing 61.8 mph.

Will 185/65R15 fit on 185/60R15 wheels?

Both use a 15" rim, so the wheel diameter matches; check the wheel's width range for a 185 mm tire and the fender clearance.