265/75R16 vs 305/70R16
305/70R16 is outside the ±3% rule as a replacement for 265/75R16: the diameter differs by +3.67%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 305/70R16 on a car calibrated for 265/75R16, the speedometer reads 57.9 mph when you're really doing 60, and the odometer under-counts by 3.7%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.1 mph |
| 45 mph | 46.7 mph |
| 60 mph | 62.2 mph |
| 70 mph | 72.6 mph |
| 80 mph | 82.9 mph |
Other sizes close to 265/75R16
Questions
Can I replace 265/75R16 with 305/70R16?
305/70R16 is outside the ±3% rule as a replacement for 265/75R16: the diameter differs by +3.67%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 265/75R16 and 305/70R16?
305/70R16 is 1.16" taller and 40 mm wider; the sidewall is +0.58". At an indicated 60 mph you'd actually be doing 62.2 mph.
Will 305/70R16 fit on 265/75R16 wheels?
Both use a 16" rim, so the wheel diameter matches; check the wheel's width range for a 305 mm tire and the fender clearance.