What is the diameter difference between 225/50R17 and 245/40R19?

225/50R17 has an overall diameter of 25.86 inches (657 mm). 245/40R19 is 26.72 inches (679 mm). That's a 0.86 inch (22 mm) difference — 245/40R19 is taller.

Will 245/40R19 cause speedometer error on a car fitted with 225/50R17?

Swapping 225/50R17 for 245/40R19 produces a speedometer error of about 3.3%. 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?

225/50R17 turns 780 revs per mile. 245/40R19 turns 755 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.

What's the sidewall height difference?

225/50R17 has a sidewall of 113 mm (4.43 in). 245/40R19 sidewall is 98 mm (3.86 in). Lower-profile sidewalls give sharper steering response but less bump compliance.

Is 245/40R19 a safe plus-size upgrade from 225/50R17?

A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.3%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.

Tire size comparison

225/50R17 vs 245/40R19

Overall diameter, sidewall, revs per mile, and speedometer error — 245/40R19 is the taller tire, with a 3.3% speedo delta when swapping.

225/50R17

25.86in

657 mm overall diameter

245/40R19

26.72in

679 mm overall diameter

Diameter Δ

0.86 in

Speedo error

3.3%

225/50R17 revs/mi

780

245/40R19 revs/mi

755

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	225/50R17	245/40R19
Section width	225 mm	245 mm
Aspect ratio	50	40
Wheel diameter	17″	19″
Sidewall height	113 mm	98 mm
Overall diameter	25.86 in (657 mm)	26.72 in (679 mm)
Circumference	81.24 in	83.93 in
Revolutions / mile	780	755

Other comparisons for these sizes

205/50R17 vs 225/50R17 215/55R17 vs 225/50R17 215/50R17 vs 225/50R17 225/50R17 vs 235/45R18 225/50R17 vs 225/45R18 225/50R17 vs 225/45R17 225/50R17 vs 235/45R17 235/45R18 vs 245/40R19 245/45R18 vs 245/40R19 225/40R19 vs 245/40R19

FAQ

Frequently asked

What is the diameter difference between 225/50R17 and 245/40R19?: 225/50R17 has an overall diameter of 25.86 inches (657 mm). 245/40R19 is 26.72 inches (679 mm). That's a 0.86 inch (22 mm) difference — 245/40R19 is taller.
Will 245/40R19 cause speedometer error on a car fitted with 225/50R17?: Swapping 225/50R17 for 245/40R19 produces a speedometer error of about 3.3%. 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?: 225/50R17 turns 780 revs per mile. 245/40R19 turns 755 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.
What's the sidewall height difference?: 225/50R17 has a sidewall of 113 mm (4.43 in). 245/40R19 sidewall is 98 mm (3.86 in). Lower-profile sidewalls give sharper steering response but less bump compliance.
Is 245/40R19 a safe plus-size upgrade from 225/50R17?: A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.3%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.