335/30R18 vs 225/50R18
225/50R18 is outside the ±3% rule as a replacement for 335/30R18: the diameter differs by +3.65%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 225/50R18 on a car calibrated for 335/30R18, the speedometer reads 57.9 mph when you're really doing 60, and the odometer under-counts by 3.6%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.1 mph |
| 45 mph | 46.6 mph |
| 60 mph | 62.2 mph |
| 70 mph | 72.6 mph |
| 80 mph | 82.9 mph |
Other sizes close to 335/30R18
- 335/30R18 vs 225/45R18+0.23%
- 335/30R18 vs 245/40R18-0.76%
- 335/30R18 vs 225/40R18-3.19%
- 335/30R18 vs 225/50R17-0.21%
- 335/30R18 vs 245/45R18+2.96%
- 335/30R18 vs 235/45R18+1.60%
- 335/30R18 vs 235/40R18-1.98%
- 335/30R18 vs 245/45R17-0.90%
- 335/30R18 vs 255/35R19+0.44%
- 335/30R18 vs 255/35R18-3.42%
- 335/30R18 vs 255/40R18+0.46%
- 335/30R18 vs 245/35R19-0.62%
Questions
Can I replace 335/30R18 with 225/50R18?
225/50R18 is outside the ±3% rule as a replacement for 335/30R18: the diameter differs by +3.65%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 335/30R18 and 225/50R18?
225/50R18 is 0.94" taller and 110 mm narrower; the sidewall is +0.47". At an indicated 60 mph you'd actually be doing 62.2 mph.
Will 225/50R18 fit on 335/30R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 225 mm tire and the fender clearance.