295/35R18 vs 295/40R18
295/40R18 is outside the ±3% rule as a replacement for 295/35R18: the diameter differs by +4.44%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 295/40R18 on a car calibrated for 295/35R18, the speedometer reads 57.4 mph when you're really doing 60, and the odometer under-counts by 4.4%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.3 mph |
| 45 mph | 47.0 mph |
| 60 mph | 62.7 mph |
| 70 mph | 73.1 mph |
| 80 mph | 83.6 mph |
Other sizes close to 295/35R18
- 295/35R18 vs 225/45R18-0.60%
- 295/35R18 vs 245/40R18-1.58%
- 295/35R18 vs 225/40R18-3.99%
- 295/35R18 vs 245/45R18+2.11%
- 295/35R18 vs 235/50R18+4.29%
- 295/35R18 vs 235/45R18+0.75%
- 295/35R18 vs 215/55R17+0.69%
- 295/35R18 vs 235/40R18-2.79%
- 295/35R18 vs 225/50R18+2.79%
- 295/35R18 vs 255/35R19-0.39%
- 295/35R18 vs 255/35R18-4.22%
- 295/35R18 vs 255/40R18-0.38%
Questions
Can I replace 295/35R18 with 295/40R18?
295/40R18 is outside the ±3% rule as a replacement for 295/35R18: the diameter differs by +4.44%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 295/35R18 and 295/40R18?
295/40R18 is 1.16" taller and 0 mm wider; the sidewall is +0.58". At an indicated 60 mph you'd actually be doing 62.7 mph.
Will 295/40R18 fit on 295/35R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 295 mm tire and the fender clearance.