215/70R15 vs 235/70R15
235/70R15 is outside the ±3% rule as a replacement for 215/70R15: the diameter differs by +4.11%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 235/70R15 on a car calibrated for 215/70R15, the speedometer reads 57.6 mph when you're really doing 60, and the odometer under-counts by 4.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.2 mph |
| 45 mph | 46.8 mph |
| 60 mph | 62.5 mph |
| 70 mph | 72.9 mph |
| 80 mph | 83.3 mph |
Other sizes close to 215/70R15
Questions
Can I replace 215/70R15 with 235/70R15?
235/70R15 is outside the ±3% rule as a replacement for 215/70R15: the diameter differs by +4.11%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 215/70R15 and 235/70R15?
235/70R15 is 1.10" taller and 20 mm wider; the sidewall is +0.55". At an indicated 60 mph you'd actually be doing 62.5 mph.
Will 235/70R15 fit on 215/70R15 wheels?
Both use a 15" rim, so the wheel diameter matches; check the wheel's width range for a 235 mm tire and the fender clearance.