235/55R19 means a 235 mm section width, a 55% aspect ratio, radial construction and a 19-inch wheel. That works out to a 129.3 mm sidewall and an overall diameter of about 741.1 mm.
The aspect ratio is a proportion, not a measurement: the same 45 gives a different sidewall height on a different width, and that changes both ride and handling. A lower ratio holds a corner better and transmits more of the road surface.
A frequent fitment on mid-size SUVs like the Sorento and Santa Fe.
What each number means
| 235 | Section width 235 mm |
|---|---|
| 55 | Aspect ratio 129.3 mm (55% × 235 mm) |
| R | Construction Radial |
| 19 | Wheel diameter 482.6 mm |
| Overall diameter | 741.1 mm 29.2" |
Compatible alternatives
| Size | Overall diameter | Diameter difference |
|---|---|---|
| 235/60R18 | 739.2 mm | -0.3% |
| 245/50R19 | 727.6 mm | -1.8% |
| 255/50R19 | 737.6 mm | -0.5% |
Load index and speed rating
After the size itself, a tyre wall carries something like 91V. The number is the load index — the weight one tyre can carry, 91 meaning 615 kg — and the letter is the speed rating, V meaning 240 km/h.
Never drop below the load index the manufacturer specified, even if the size matches. The original specification is printed on the label inside the driver’s door.