245/75R17 vs 305/65R17
305/65R17 is outside the ±3% rule as a replacement for 245/75R17: the diameter differs by +3.63%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 305/65R17 on a car calibrated for 245/75R17, 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 | 72.5 mph |
| 80 mph | 82.9 mph |
Other sizes close to 245/75R17
- 245/75R17 vs 265/70R17+0.44%
- 245/75R17 vs 265/75R16+0.58%
- 245/75R17 vs 245/70R17-3.07%
- 245/75R17 vs 285/70R17+3.94%
- 245/75R17 vs 265/65R18+0.30%
- 245/75R17 vs 265/65R17-2.88%
- 245/75R17 vs 235/85R16+0.83%
- 245/75R17 vs 235/80R17+1.06%
- 245/75R17 vs 255/65R17-4.50%
- 245/75R17 vs 255/70R17-1.31%
- 245/75R17 vs 255/75R17+1.88%
- 245/75R17 vs 235/75R17-1.88%
Questions
Can I replace 245/75R17 with 305/65R17?
305/65R17 is outside the ±3% rule as a replacement for 245/75R17: the diameter differs by +3.63%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 245/75R17 and 305/65R17?
305/65R17 is 1.14" taller and 60 mm wider; the sidewall is +0.57". At an indicated 60 mph you'd actually be doing 62.2 mph.
Will 305/65R17 fit on 245/75R17 wheels?
Both use a 17" rim, so the wheel diameter matches; check the wheel's width range for a 305 mm tire and the fender clearance.