205/55R18 tire size
A 205/55R18 tire is 26.88 inches (682.7 mm) tall, 8.07 in (205 mm) wide and fits a 18-inch wheel. In inch notation it is roughly a 26.9x8.1R18.
| Overall diameter | 26.88 in | 682.7 mm |
|---|---|---|
| Section width | 8.07 in | 205 mm |
| Sidewall height | 4.44 in | 112.8 mm |
| Circumference | 84.44 in | 2,145 mm |
| Revolutions | 750.4 per mile | 466.3 per km |
| Rim diameter | 18 in | 457.2 mm |
Compare 205/55R18 with another size
Alternative sizes on the same 18-inch wheel
Sizes in use within ±3 % of the overall diameter of 205/55R18:
Plus and minus sizes for 205/55R18
| Size | Wheel | Diameter | Difference |
|---|---|---|---|
| 185/75R16 | Minus 2 (16 in) | 26.93 in | +0.18% |
| 215/65R16 | Minus 2 (16 in) | 27.00 in | +0.47% |
| 195/70R16 | Minus 2 (16 in) | 26.75 in | −0.48% |
| 175/80R16 | Minus 2 (16 in) | 27.02 in | +0.54% |
| 225/55R17 | Minus 1 (17 in) | 26.74 in | −0.50% |
| 205/60R17 | Minus 1 (17 in) | 26.69 in | −0.72% |
| 245/50R17 | Minus 1 (17 in) | 26.65 in | −0.86% |
| 215/60R17 | Minus 1 (17 in) | 27.16 in | +1.04% |
| 225/45R19 | Plus 1 (19 in) | 26.97 in | +0.35% |
| 255/40R19 | Plus 1 (19 in) | 27.03 in | +0.57% |
| 245/40R19 | Plus 1 (19 in) | 26.72 in | −0.60% |
| 205/50R19 | Plus 1 (19 in) | 27.07 in | +0.72% |
| 245/35R20 | Plus 2 (20 in) | 26.75 in | −0.47% |
| 255/35R20 | Plus 2 (20 in) | 27.03 in | +0.56% |
| 225/40R20 | Plus 2 (20 in) | 27.09 in | +0.78% |
| 235/35R20 | Plus 2 (20 in) | 26.48 in | −1.49% |
Vehicles approved with 205/55R18 tires
Models whose Swiss type approval lists 205/55R18 as a standard or optional size (1,201 approvals in total). Always check your own vehicle's placard or papers.
Source: Swiss Federal Roads Office (FEDRO/ASTRA), open government data. Original data (downloaded 2026-09-29). Data processed by us; errors in processing are ours, not the publisher's.
Nearby 18-inch sizes
Reading the 205/55R18 size
- 205 — section width in millimetres (8.07 in).
- 55 — aspect ratio: the sidewall is 55 % of the width, 112.8 mm.
- R — radial construction (ZR on the sidewall means a high-speed rated radial; the dimensions are the same).
- 18 — fits a 18-inch diameter wheel.
The load index and speed rating (for example 91V) follow the size on the sidewall. They must meet at least the values on your vehicle's tire placard.