What is the diameter difference between 225/35R19 and 225/40R19?

225/35R19 has an overall diameter of 25.2 inches (640 mm). 225/40R19 is 26.09 inches (663 mm). That's a 0.89 inch (23 mm) difference — 225/40R19 is taller.

Will 225/40R19 cause speedometer error on a car fitted with 225/35R19?

Swapping 225/35R19 for 225/40R19 produces a speedometer error of about 3.5%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 62.1 mph. Anything under 3% is usually acceptable without recalibration.

How many revolutions per mile does each size do?

225/35R19 turns 800 revs per mile. 225/40R19 turns 773 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.

What's the sidewall height difference?

225/35R19 has a sidewall of 79 mm (3.1 in). 225/40R19 sidewall is 90 mm (3.54 in). Lower-profile sidewalls give sharper steering response but less bump compliance.

Is 225/40R19 a safe plus-size upgrade from 225/35R19?

A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.5%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.

Tire size comparison

225/35R19 vs 225/40R19

Overall diameter, sidewall, revs per mile, and speedometer error — 225/40R19 is the taller tire, with a 3.5% speedo delta when swapping.

225/35R19

25.2in

640 mm overall diameter

225/40R19

26.09in

663 mm overall diameter

Diameter Δ

0.89 in

Speedo error

3.5%

225/35R19 revs/mi

800

225/40R19 revs/mi

773

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	225/35R19	225/40R19
Section width	225 mm	225 mm
Aspect ratio	35	40
Wheel diameter	19″	19″
Sidewall height	79 mm	90 mm
Overall diameter	25.2 in (640 mm)	26.09 in (663 mm)
Circumference	79.17 in	81.95 in
Revolutions / mile	800	773

Other comparisons for these sizes

205/50R17 vs 225/40R19 215/40R18 vs 225/35R19 225/40R18 vs 225/35R19 225/45R18 vs 225/40R19 225/35R19 vs 235/35R19 225/35R19 vs 245/35R19 225/40R19 vs 245/40R19 225/40R19 vs 235/35R19

FAQ

Frequently asked

What is the diameter difference between 225/35R19 and 225/40R19?: 225/35R19 has an overall diameter of 25.2 inches (640 mm). 225/40R19 is 26.09 inches (663 mm). That's a 0.89 inch (23 mm) difference — 225/40R19 is taller.
Will 225/40R19 cause speedometer error on a car fitted with 225/35R19?: Swapping 225/35R19 for 225/40R19 produces a speedometer error of about 3.5%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 62.1 mph. Anything under 3% is usually acceptable without recalibration.
How many revolutions per mile does each size do?: 225/35R19 turns 800 revs per mile. 225/40R19 turns 773 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.
What's the sidewall height difference?: 225/35R19 has a sidewall of 79 mm (3.1 in). 225/40R19 sidewall is 90 mm (3.54 in). Lower-profile sidewalls give sharper steering response but less bump compliance.
Is 225/40R19 a safe plus-size upgrade from 225/35R19?: A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.5%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.