285/50R18 dimensions
| Measure | Inches | Millimetres |
|---|---|---|
| Overall height | 29.22 in | 742 mm |
| Section width | 11.22 in | 285 mm |
| Sidewall height | 5.61 in | 142.5 mm |
| Wheel diameter | 18 in | 457 mm |
| Circumference | 91.8 in | 2,332 mm |
| Revolutions per mile | 690.2 |
The math
| Step | Math | Result |
|---|---|---|
| Sidewall | 285 × 50% = 142.5 mm ÷ 25.4 | 5.61 in |
| Overall height | 18 + 2 × 5.61 | 29.22 in |
| Width | 285 mm ÷ 25.4 | 11.22 in |
| Circumference | π × 29.22 | 91.8 in |
| Revs per mile | 63,360 ÷ 91.8 | 690.2 |
With a 5.6 in sidewall this is a tall sidewall with more cushion and flex. Real tires vary by brand and model, and the loaded radius under the vehicle is a bit smaller than this unloaded figure.
One step either way on a 18 in wheel
Each row changes one thing and shows the height change against 285/50R18, plus what 60 mph on the speedometer would really be if you swapped to that size.
| Change | Size | Height | Height change | 60 mph shows as | Verdict |
|---|---|---|---|---|---|
| Wider | 295/50R18 (compare) | 29.6 in | +1.3% | 60.8 mph | Close match |
| Narrower | 275/50R18 (compare) | 28.8 in | -1.3% | 59.2 mph | Close match |
| Taller sidewall | 285/55R18 (compare) | 30.3 in | +3.8% | 62.3 mph | Check clearance |
| Shorter sidewall | 285/45R18 (compare) | 28.1 in | -3.8% | 57.7 mph | Check clearance |
| Wider, shorter sidewall | 295/45R18 (compare) | 28.5 in | -2.6% | 58.4 mph | Close match |
| Narrower, taller sidewall | 275/55R18 (compare) | 29.9 in | +2.4% | 61.4 mph | Close match |
Calculated sizes within ±3% on other wheels
Plus and minus sizes that keep the overall height within about 3% (a rule of thumb from Discount Tire and 1010tires), widths within 30 mm. Calculated, not a list of tires on sale: check that a tire exists in that size.
17 in wheels (one wheel size smaller)
| Size | Height | Height change | Width change |
|---|---|---|---|
| 285/55R17 (compare) | 29.3 in | +0.4% | +0 mm |
| 255/60R17 (compare) | 29.0 in | -0.6% | -30 mm |
| 315/50R17 (compare) | 29.4 in | +0.6% | +30 mm |
| 305/50R17 (compare) | 29.0 in | -0.7% | +20 mm |
19 in wheels (one wheel size larger)
| Size | Height | Height change | Width change |
|---|---|---|---|
| 285/45R19 (compare) | 29.1 in | -0.4% | +0 mm |
| 255/50R19 (compare) | 29.0 in | -0.6% | -30 mm |
| 265/50R19 (compare) | 29.4 in | +0.7% | -20 mm |
| 295/45R19 (compare) | 29.5 in | +0.8% | +10 mm |
20 in wheels (two wheel sizes larger)
| Size | Height | Height change | Width change |
|---|---|---|---|
| 295/40R20 (compare) | 29.3 in | +0.2% | +10 mm |
| 265/45R20 (compare) | 29.4 in | +0.6% | -20 mm |
| 255/45R20 (compare) | 29.0 in | -0.6% | -30 mm |
| 285/40R20 (compare) | 29.0 in | -0.8% | +0 mm |
Try it with your numbers
Compare 285/50R18 with another size · Convert to metric or find a 33 in size · Sizes that fit my wheel
Calculated from the size alone. Real tires vary a little by brand and model, and the loaded radius is a bit smaller. Confirm the wheel width range, clearance, load index and speed rating for your vehicle. See how to read a tire size, the load index chart and the speed rating chart.
Browse: all sizes in inches · 275/70R18 · 285/60R18.