What is the diameter difference between 185/65R14 and 185/60R15?

185/65R14 has an overall diameter of 23.47 inches (596 mm). 185/60R15 is 23.74 inches (603 mm). That's a 0.27 inch (7 mm) difference — 185/60R15 is taller.

Will 185/60R15 cause speedometer error on a car fitted with 185/65R14?

Swapping 185/65R14 for 185/60R15 produces a speedometer error of about 1.2%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 60.7 mph. Anything under 3% is usually acceptable without recalibration.

How many revolutions per mile does each size do?

185/65R14 turns 859 revs per mile. 185/60R15 turns 850 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.

What's the sidewall height difference?

185/65R14 has a sidewall of 120 mm (4.73 in). 185/60R15 sidewall is 111 mm (4.37 in). Lower-profile sidewalls give sharper steering response but less bump compliance.

Is 185/60R15 a safe plus-size upgrade from 185/65R14?

A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 1.2%. This swap is within the typical safe range; speedometer and ABS calibration should remain close to factory.

Tire size comparison

185/65R14 vs 185/60R15

Overall diameter, sidewall, revs per mile, and speedometer error — 185/60R15 is the taller tire, with a 1.2% speedo delta when swapping.

185/65R14

23.47in

596 mm overall diameter

185/60R15

23.74in

603 mm overall diameter

Diameter Δ

0.27 in

Speedo error

1.2%

185/65R14 revs/mi

859

185/60R15 revs/mi

850

Within the ±3% overall-diameter band usually considered safe for plus-sizing — speedometer and ABS calibration should stay close to factory.

Full spec

Side by side

Metric	185/65R14	185/60R15
Section width	185 mm	185 mm
Aspect ratio	65	60
Wheel diameter	14″	15″
Sidewall height	120 mm	111 mm
Overall diameter	23.47 in (596 mm)	23.74 in (603 mm)
Circumference	73.73 in	74.58 in
Revolutions / mile	859	850

Other comparisons for these sizes

175/65R14 vs 185/60R15 175/65R14 vs 185/65R14 185/65R14 vs 195/60R15 185/65R14 vs 205/55R16 185/60R15 vs 205/50R17 185/60R15 vs 195/60R15

FAQ

Frequently asked

What is the diameter difference between 185/65R14 and 185/60R15?: 185/65R14 has an overall diameter of 23.47 inches (596 mm). 185/60R15 is 23.74 inches (603 mm). That's a 0.27 inch (7 mm) difference — 185/60R15 is taller.
Will 185/60R15 cause speedometer error on a car fitted with 185/65R14?: Swapping 185/65R14 for 185/60R15 produces a speedometer error of about 1.2%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 60.7 mph. Anything under 3% is usually acceptable without recalibration.
How many revolutions per mile does each size do?: 185/65R14 turns 859 revs per mile. 185/60R15 turns 850 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.
What's the sidewall height difference?: 185/65R14 has a sidewall of 120 mm (4.73 in). 185/60R15 sidewall is 111 mm (4.37 in). Lower-profile sidewalls give sharper steering response but less bump compliance.
Is 185/60R15 a safe plus-size upgrade from 185/65R14?: A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 1.2%. This swap is within the typical safe range; speedometer and ABS calibration should remain close to factory.