255/60R20 vs 305/50R20 tire size
305/50R20 vs 255/60R20, diameter
-0.1% shorter
- Speedometer
- 60.1 mph
- At a true 60 mph
- Diameter
- 32.01 in
- Was 32.05 in
- Revs per mile
- 630
- Was 629
- 3% guideline
- Within
Car built for 255/60R20, now on 305/50R20.
255/60R20 and 305/50R20
| Measure | 255/60R20 | 305/50R20 | Difference |
|---|---|---|---|
| Width, mm | 255 | 305 | +50 |
| Sidewall, % of width | 60 | 50 | -10 |
| Rim, in | 20 | 20 | 0 |
| Section height, in | 6.02 | 6.00 | -0.02 |
| Diameter, in | 32.05 | 32.01 | -0.04 (-0.1%) |
| Circumference, in | 100.7 | 100.6 | -0.1 |
| Revs per mile | 629 | 630 | +1 (+0.1%) |
Fitting 305/50R20 instead of 255/60R20
Within the usual 3% diameter guideline.
- 50 mm wider. Check rubbing at full lock.
Cars with 255/60R20
What this cannot tell you
Diameter within 3% is a common shop guideline, not a maker spec.
Load index, offset and clearance are not in this data.
- Two or more sources agree
- One source
- Model-level or estimate
- Sources differ