265/40R18 tire size
A 265/40R18 tire is 26.35 inches (669.2 mm) tall, 10.43 in (265 mm) wide and fits a 18-inch wheel. In inch notation it is roughly a 26.3x10.4R18.
| Overall diameter | 26.35 in | 669.2 mm |
|---|---|---|
| Section width | 10.43 in | 265 mm |
| Sidewall height | 4.17 in | 106.0 mm |
| Circumference | 82.77 in | 2,102 mm |
| Revolutions | 765.5 per mile | 475.7 per km |
| Rim diameter | 18 in | 457.2 mm |
Compare 265/40R18 with another size
Alternative sizes on the same 18-inch wheel
Sizes in use within ±3 % of the overall diameter of 265/40R18:
Plus and minus sizes for 265/40R18
| Size | Wheel | Diameter | Difference |
|---|---|---|---|
| 245/55R16 | Minus 2 (16 in) | 26.61 in | +1.00% |
| 245/50R16 | Minus 2 (16 in) | 25.65 in | −2.66% |
| 235/60R16 | Minus 2 (16 in) | 27.10 in | +2.87% |
| 235/50R17 | Minus 1 (17 in) | 26.25 in | −0.36% |
| 245/50R17 | Minus 1 (17 in) | 26.65 in | +1.14% |
| 255/45R17 | Minus 1 (17 in) | 26.04 in | −1.18% |
| 285/40R17 | Minus 1 (17 in) | 25.98 in | −1.40% |
| 265/35R19 | Plus 1 (19 in) | 26.30 in | −0.16% |
| 235/40R19 | Plus 1 (19 in) | 26.40 in | +0.21% |
| 305/30R19 | Plus 1 (19 in) | 26.20 in | −0.54% |
| 275/35R19 | Plus 1 (19 in) | 26.58 in | +0.88% |
| 265/30R20 | Plus 2 (20 in) | 26.26 in | −0.33% |
| 235/35R20 | Plus 2 (20 in) | 26.48 in | +0.49% |
| 275/30R20 | Plus 2 (20 in) | 26.50 in | +0.57% |
| 255/30R20 | Plus 2 (20 in) | 26.02 in | −1.23% |
| 295/25R21 | Plus 3 (21 in) | 26.81 in | +1.75% |
Vehicles approved with 265/40R18 tires
Models whose Swiss type approval lists 265/40R18 as a standard or optional size (94 approvals in total). Always check your own vehicle's placard or papers.
- Mercedes-Benz C-Class
- Porsche Cayman
- BMW M3
- Porsche Boxster
- Alpina B3
- Porsche 911
- Mercedes-Benz S-Class
- Mercedes-Benz CL
- Ferrari F355
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
- 245/35R18 (−6.1%)
- 245/40R18 (−2.4%)
- 245/45R18 (+1.3%)
- 245/50R18 (+4.9%)
- 255/35R18 (−5.0%)
- 255/40R18 (−1.2%)
- 255/45R18 (+2.6%)
- 255/50R18 (+6.4%)
- 265/35R18 (−4.0%)
- 265/45R18 (+4.0%)
- 275/35R18 (−2.9%)
- 275/40R18 (+1.2%)
- 275/45R18 (+5.3%)
- 285/30R18 (−6.1%)
- 285/35R18 (−1.9%)
- 285/40R18 (+2.4%)
- 285/45R18 (+6.6%)
- 285/50R18 (+10.9%)
Reading the 265/40R18 size
- 265 — section width in millimetres (10.43 in).
- 40 — aspect ratio: the sidewall is 40 % of the width, 106.0 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.