215/55R16 vs 225/50R16
Diameter -1.79% · Speedo at 60 mph reads 58.9 mph actual · Ground clearance -5.8 mm
Generally safe — within the 3% tolerance
The diameter difference is ≤3%, which is the widely-accepted fitment tolerance for speedometer accuracy and ABS/traction-control calibration. Verify clearance and load rating with a tire professional before installing.
Speedometer effect
When the vehicle's speedometer (calibrated to 215/55R16) reads 60 mph, the actual speed with 225/50R16 mounted is:
Speedometer error: -1.78% · Odometer reads low by 1.78%
Full comparison
| Measurement | 215/55R16 | 225/50R16 | Delta |
|---|---|---|---|
| Overall diameter | 25.31" | 24.86" | -1.79% |
| Section width | 215 mm | 225 mm | +10 mm |
| Sidewall height | 118.25 mm | 112.5 mm | -5.75 mm |
| Rim diameter | 16" | 16" | +0" |
| Circumference | 2020 mm | 1984 mm | -36 mm |
| Revs / mile | 797 | 811 | 15 |
| Ground clearance change | -5.8 mm | ||
Questions about this swap
What is the diameter difference between 215/55R16 and 225/50R16?
225/50R16 is 1.79% smaller in overall diameter than 215/55R16 — a difference of 11.5 mm (0.45 inches).
How does 225/50R16 affect the speedometer if the car was calibrated for 215/55R16?
When the speedometer reads 60 mph (calibrated for 215/55R16), the actual speed with 225/50R16 is 58.9 mph — an error of -1.78%.
Is it safe to replace 215/55R16 with 225/50R16?
Generally safe — within the 3% tolerance. The diameter difference is ≤3%, which is the widely-accepted fitment tolerance for speedometer accuracy and ABS/traction-control calibration. Verify clearance and load rating with a tire professional before installing.
All calculations use standard ETRTO formulas. Confirm fitment with a qualified tire professional and your vehicle's door-placard before purchasing.