225/45R18 vs 305/30R19 tire size
305/30R19 vs 225/45R18, diameter
+0.9% taller
- Speedometer
- 59.5 mph
- At a true 60 mph
- Diameter
- 26.20 in
- Was 25.97 in
- Revs per mile
- 770
- Was 777
- 3% guideline
- Within
Car built for 225/45R18, now on 305/30R19.
225/45R18 and 305/30R19
| Measure | 225/45R18 | 305/30R19 | Difference |
|---|---|---|---|
| Width, mm | 225 | 305 | +80 |
| Sidewall, % of width | 45 | 30 | -15 |
| Rim, in | 18 | 19 | +1 |
| Section height, in | 3.99 | 3.60 | -0.38 |
| Diameter, in | 25.97 | 26.20 | +0.23 (+0.9%) |
| Circumference, in | 81.6 | 82.3 | +0.7 |
| Revs per mile | 777 | 770 | -7 (-0.9%) |
Fitting 305/30R19 instead of 225/45R18
Within the usual 3% diameter guideline.
- Needs 19 in wheels.
- 80 mm wider. Check rubbing at full lock.
Cars with 225/45R18
Cars with 305/30R19
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