What is the diameter difference between 215/55R17 and 215/50R17?

215/55R17 has an overall diameter of 26.31 inches (668 mm). 215/50R17 is 25.46 inches (647 mm). That's a 0.85 inch (22 mm) difference — 215/50R17 is shorter.

Will 215/50R17 cause speedometer error on a car fitted with 215/55R17?

Swapping 215/55R17 for 215/50R17 produces a speedometer error of about 3.2%. Your speedometer will read higher than your actual speed — a 60 mph indicated reading is really 58.1 mph. Anything under 3% is usually acceptable without recalibration.

How many revolutions per mile does each size do?

215/55R17 turns 767 revs per mile. 215/50R17 turns 792 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.

What's the sidewall height difference?

215/55R17 has a sidewall of 118 mm (4.66 in). 215/50R17 sidewall is 108 mm (4.23 in). Lower-profile sidewalls give sharper steering response but less bump compliance.

Is 215/50R17 a safe plus-size upgrade from 215/55R17?

A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.2%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.

Tire size comparison

215/55R17 vs 215/50R17

Overall diameter, sidewall, revs per mile, and speedometer error — 215/55R17 is the taller tire, with a 3.2% speedo delta when swapping.

215/55R17

26.31in

668 mm overall diameter

215/50R17

25.46in

647 mm overall diameter

Diameter Δ

0.85 in

Speedo error

3.2%

215/55R17 revs/mi

767

215/50R17 revs/mi

792

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	215/55R17	215/50R17
Section width	215 mm	215 mm
Aspect ratio	55	50
Wheel diameter	17″	17″
Sidewall height	118 mm	108 mm
Overall diameter	26.31 in (668 mm)	25.46 in (647 mm)
Circumference	82.66 in	80 in
Revolutions / mile	767	792

Other comparisons for these sizes

195/65R15 vs 215/55R17 195/60R15 vs 215/50R17 205/55R16 vs 215/50R17 205/60R16 vs 215/55R17 215/60R16 vs 215/55R17 205/50R17 vs 215/50R17 215/55R17 vs 235/55R17 215/55R17 vs 225/50R17 215/50R17 vs 225/45R18 215/50R17 vs 225/50R17

FAQ

Frequently asked

What is the diameter difference between 215/55R17 and 215/50R17?: 215/55R17 has an overall diameter of 26.31 inches (668 mm). 215/50R17 is 25.46 inches (647 mm). That's a 0.85 inch (22 mm) difference — 215/50R17 is shorter.
Will 215/50R17 cause speedometer error on a car fitted with 215/55R17?: Swapping 215/55R17 for 215/50R17 produces a speedometer error of about 3.2%. Your speedometer will read higher than your actual speed — a 60 mph indicated reading is really 58.1 mph. Anything under 3% is usually acceptable without recalibration.
How many revolutions per mile does each size do?: 215/55R17 turns 767 revs per mile. 215/50R17 turns 792 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.
What's the sidewall height difference?: 215/55R17 has a sidewall of 118 mm (4.66 in). 215/50R17 sidewall is 108 mm (4.23 in). Lower-profile sidewalls give sharper steering response but less bump compliance.
Is 215/50R17 a safe plus-size upgrade from 215/55R17?: A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.2%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.