155/70R19 vs 245/40R20 tire size
245/40R20 vs 155/70R19, diameter
+0.6% taller
- Speedometer
- 59.6 mph
- At a true 60 mph
- Diameter
- 27.72 in
- Was 27.54 in
- Revs per mile
- 728
- Was 732
- 3% guideline
- Within
Car built for 155/70R19, now on 245/40R20.
155/70R19 and 245/40R20
| Measure | 155/70R19 | 245/40R20 | Difference |
|---|---|---|---|
| Width, mm | 155 | 245 | +90 |
| Sidewall, % of width | 70 | 40 | -30 |
| Rim, in | 19 | 20 | +1 |
| Section height, in | 4.27 | 3.86 | -0.41 |
| Diameter, in | 27.54 | 27.72 | +0.17 (+0.6%) |
| Circumference, in | 86.5 | 87.1 | +0.5 |
| Revs per mile | 732 | 728 | -5 (-0.6%) |
Fitting 245/40R20 instead of 155/70R19
Within the usual 3% diameter guideline.
- Needs 20 in wheels.
- 90 mm wider. Check rubbing at full lock.
Cars with 155/70R19
Cars with 245/40R20
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