235/45R19 vs 305/30R20 tire size
305/30R20 vs 235/45R19, diameter
-0.4% shorter
- Speedometer
- 60.3 mph
- At a true 60 mph
- Diameter
- 27.20 in
- Was 27.33 in
- Revs per mile
- 741
- Was 738
- 3% guideline
- Within
Car built for 235/45R19, now on 305/30R20.
235/45R19 and 305/30R20
| Measure | 235/45R19 | 305/30R20 | Difference |
|---|---|---|---|
| Width, mm | 235 | 305 | +70 |
| Sidewall, % of width | 45 | 30 | -15 |
| Rim, in | 19 | 20 | +1 |
| Section height, in | 4.16 | 3.60 | -0.56 |
| Diameter, in | 27.33 | 27.20 | -0.12 (-0.4%) |
| Circumference, in | 85.8 | 85.5 | -0.4 |
| Revs per mile | 738 | 741 | +3 (+0.4%) |
Fitting 305/30R20 instead of 235/45R19
Within the usual 3% diameter guideline.
- Needs 20 in wheels.
- 70 mm wider. Check rubbing at full lock.
- Shorter sidewall: 0.6 in less.
Cars with 235/45R19
Cars with 305/30R20
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