What is the diameter difference between 195/65R15 and 205/65R15?

195/65R15 has an overall diameter of 24.98 inches (635 mm). 205/65R15 is 25.49 inches (648 mm). That's a 0.51 inch (13 mm) difference — 205/65R15 is taller.

Will 205/65R15 cause speedometer error on a car fitted with 195/65R15?

Swapping 195/65R15 for 205/65R15 produces a speedometer error of about 2%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 61.2 mph. Anything under 3% is usually acceptable without recalibration.

How many revolutions per mile does each size do?

195/65R15 turns 807 revs per mile. 205/65R15 turns 791 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.

What's the sidewall height difference?

195/65R15 has a sidewall of 127 mm (4.99 in). 205/65R15 sidewall is 133 mm (5.25 in). Lower-profile sidewalls give sharper steering response but less bump compliance.

Is 205/65R15 a safe plus-size upgrade from 195/65R15?

A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 2%. This swap is within the typical safe range; speedometer and ABS calibration should remain close to factory.

Tire size comparison

195/65R15 vs 205/65R15

Overall diameter, sidewall, revs per mile, and speedometer error — 205/65R15 is the taller tire, with a 2% speedo delta when swapping.

195/65R15

24.98in

635 mm overall diameter

205/65R15

25.49in

648 mm overall diameter

Diameter Δ

0.51 in

Speedo error

195/65R15 revs/mi

807

205/65R15 revs/mi

791

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	195/65R15	205/65R15
Section width	195 mm	205 mm
Aspect ratio	65	65
Wheel diameter	15″	15″
Sidewall height	127 mm	133 mm
Overall diameter	24.98 in (635 mm)	25.49 in (648 mm)
Circumference	78.48 in	80.09 in
Revolutions / mile	807	791

Other comparisons for these sizes

195/65R15 vs 205/60R16 195/65R15 vs 215/55R17 195/65R15 vs 195/60R15 205/65R15 vs 215/60R16 205/65R15 vs 205/60R16

FAQ

Frequently asked

What is the diameter difference between 195/65R15 and 205/65R15?: 195/65R15 has an overall diameter of 24.98 inches (635 mm). 205/65R15 is 25.49 inches (648 mm). That's a 0.51 inch (13 mm) difference — 205/65R15 is taller.
Will 205/65R15 cause speedometer error on a car fitted with 195/65R15?: Swapping 195/65R15 for 205/65R15 produces a speedometer error of about 2%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 61.2 mph. Anything under 3% is usually acceptable without recalibration.
How many revolutions per mile does each size do?: 195/65R15 turns 807 revs per mile. 205/65R15 turns 791 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.
What's the sidewall height difference?: 195/65R15 has a sidewall of 127 mm (4.99 in). 205/65R15 sidewall is 133 mm (5.25 in). Lower-profile sidewalls give sharper steering response but less bump compliance.
Is 205/65R15 a safe plus-size upgrade from 195/65R15?: A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 2%. This swap is within the typical safe range; speedometer and ABS calibration should remain close to factory.