What is the diameter difference between 175/65R14 and 185/60R15?

175/65R14 has an overall diameter of 22.96 inches (583 mm). 185/60R15 is 23.74 inches (603 mm). That's a 0.78 inch (20 mm) difference — 185/60R15 is taller.

Will 185/60R15 cause speedometer error on a car fitted with 175/65R14?

Swapping 175/65R14 for 185/60R15 produces a speedometer error of about 3.4%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 62 mph. Anything under 3% is usually acceptable without recalibration.

How many revolutions per mile does each size do?

175/65R14 turns 879 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?

175/65R14 has a sidewall of 114 mm (4.48 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 175/65R14?

A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.4%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.

Tire size comparison

175/65R14 vs 185/60R15

Overall diameter, sidewall, revs per mile, and speedometer error — 185/60R15 is the taller tire, with a 3.4% speedo delta when swapping.

175/65R14

22.96in

583 mm overall diameter

185/60R15

23.74in

603 mm overall diameter

Diameter Δ

0.78 in

Speedo error

3.4%

175/65R14 revs/mi

879

185/60R15 revs/mi

850

Outside the typical ±3% safe plus-size band — you may want speedometer recalibration, and this change can affect ABS or traction control behaviour.

Full spec

Side by side

Metric	175/65R14	185/60R15
Section width	175 mm	185 mm
Aspect ratio	65	60
Wheel diameter	14″	15″
Sidewall height	114 mm	111 mm
Overall diameter	22.96 in (583 mm)	23.74 in (603 mm)
Circumference	72.12 in	74.58 in
Revolutions / mile	879	850

Other comparisons for these sizes

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

FAQ

Frequently asked

What is the diameter difference between 175/65R14 and 185/60R15?: 175/65R14 has an overall diameter of 22.96 inches (583 mm). 185/60R15 is 23.74 inches (603 mm). That's a 0.78 inch (20 mm) difference — 185/60R15 is taller.
Will 185/60R15 cause speedometer error on a car fitted with 175/65R14?: Swapping 175/65R14 for 185/60R15 produces a speedometer error of about 3.4%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 62 mph. Anything under 3% is usually acceptable without recalibration.
How many revolutions per mile does each size do?: 175/65R14 turns 879 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?: 175/65R14 has a sidewall of 114 mm (4.48 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 175/65R14?: A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.4%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.