275/65R20 vs 325/60R20
325/60R20 is outside the ±3% rule as a replacement for 275/65R20: the diameter differs by +3.76%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 325/60R20 on a car calibrated for 275/65R20, the speedometer reads 57.8 mph when you're really doing 60, and the odometer under-counts by 3.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.1 mph |
| 45 mph | 46.7 mph |
| 60 mph | 62.3 mph |
| 70 mph | 72.6 mph |
| 80 mph | 83.0 mph |
Other sizes close to 275/65R20
- 275/65R20 vs 275/60R20-3.18%
- 275/65R20 vs 35x12.50R20+2.72%
- 275/65R20 vs 265/60R20-4.56%
- 275/65R20 vs 305/55R20-2.54%
- 275/65R20 vs 285/60R20-1.79%
- 275/65R20 vs 33x12.50R20-3.15%
- 275/65R20 vs 295/60R20-0.40%
- 275/65R20 vs 295/55R20-3.81%
- 275/65R20 vs 295/65R20+3.00%
- 275/65R20 vs 285/65R20+1.50%
- 275/65R20 vs 35x11.50R20+2.72%
- 275/65R20 vs 35x13.50R20+2.72%
Questions
Can I replace 275/65R20 with 325/60R20?
325/60R20 is outside the ±3% rule as a replacement for 275/65R20: the diameter differs by +3.76%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 275/65R20 and 325/60R20?
325/60R20 is 1.28" taller and 50 mm wider; the sidewall is +0.64". At an indicated 60 mph you'd actually be doing 62.3 mph.
Will 325/60R20 fit on 275/65R20 wheels?
Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 325 mm tire and the fender clearance.