245/40R18 tire size
A 245/40R18 tire is 25.72 inches (653.2 mm) tall, 9.65 in (245 mm) wide and fits a 18-inch wheel. In inch notation it is roughly a 25.7x9.6R18.
| Overall diameter | 25.72 in | 653.2 mm |
|---|---|---|
| Section width | 9.65 in | 245 mm |
| Sidewall height | 3.86 in | 98.0 mm |
| Circumference | 80.79 in | 2,052 mm |
| Revolutions | 784.2 per mile | 487.3 per km |
| Rim diameter | 18 in | 457.2 mm |
Compare 245/40R18 with another size
Alternative sizes on the same 18-inch wheel
Sizes in use within ±3 % of the overall diameter of 245/40R18:
Plus and minus sizes for 245/40R18
| Size | Wheel | Diameter | Difference |
|---|---|---|---|
| 225/55R16 | Minus 2 (16 in) | 25.74 in | +0.11% |
| 245/50R16 | Minus 2 (16 in) | 25.65 in | −0.28% |
| 215/55R16 | Minus 2 (16 in) | 25.31 in | −1.58% |
| 215/60R16 | Minus 2 (16 in) | 26.16 in | +1.71% |
| 245/45R17 | Minus 1 (17 in) | 25.68 in | −0.14% |
| 275/40R17 | Minus 1 (17 in) | 25.66 in | −0.21% |
| 225/50R17 | Minus 1 (17 in) | 25.86 in | +0.55% |
| 215/50R17 | Minus 1 (17 in) | 25.46 in | −0.98% |
| 285/30R19 | Plus 1 (19 in) | 25.73 in | +0.06% |
| 245/35R19 | Plus 1 (19 in) | 25.75 in | +0.14% |
| 275/30R19 | Plus 1 (19 in) | 25.50 in | −0.86% |
| 235/35R19 | Plus 1 (19 in) | 25.48 in | −0.93% |
| 245/30R20 | Plus 2 (20 in) | 25.79 in | +0.28% |
| 255/30R20 | Plus 2 (20 in) | 26.02 in | +1.19% |
| 225/35R20 | Plus 2 (20 in) | 26.20 in | +1.88% |
| 265/30R20 | Plus 2 (20 in) | 26.26 in | +2.11% |
Vehicles approved with 245/40R18 tires
Models whose Swiss type approval lists 245/40R18 as a standard or optional size (4,592 approvals in total). Always check your own vehicle's placard or papers.
- Audi A4
- Audi A5
- Mercedes-Benz C-Class
- Mercedes-Benz E-Class
- Audi TT
- Volvo S80
- Audi S5
- BMW 5 Series
- Volvo V70
- Audi A6
- Audi S4
- Jaguar XE
- Audi TTS
- Mercedes-Benz CLS
- Alpine A110
- Saab 9-5
- Chevrolet Corvette
- Mercedes-Benz CLA
- Aston Martin DB7
- Jaguar S-Type
- Mercedes-Benz SL
- Alpina B3
- Cadillac CTS
- Mitsubishi Lancer
- Mercedes-Benz A-Class
- BMW M3
- Lexus GS
- Mercedes-Benz SLR
- Subaru Impreza
- Subaru WRX
- Lexus GS450H
- Mercedes-Benz CL
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
- 225/35R18 (−5.9%)
- 225/40R18 (−2.4%)
- 225/45R18 (+1.0%)
- 225/50R18 (+4.4%)
- 235/35R18 (−4.8%)
- 235/40R18 (−1.2%)
- 235/45R18 (+2.4%)
- 235/50R18 (+6.0%)
- 245/35R18 (−3.8%)
- 245/45R18 (+3.8%)
- 245/50R18 (+7.5%)
- 255/35R18 (−2.7%)
- 255/40R18 (+1.2%)
- 255/45R18 (+5.1%)
- 255/50R18 (+9.0%)
- 265/35R18 (−1.6%)
- 265/40R18 (+2.4%)
- 265/45R18 (+6.5%)
Reading the 245/40R18 size
- 245 — section width in millimetres (9.65 in).
- 40 — aspect ratio: the sidewall is 40 % of the width, 98.0 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.