25.0" tall, 7.3" wide, 4.0" sidewall
A 185/55R17 tire is 25.0 inches (635 mm) tall and 7.3 inches wide. The sidewall is 55% of the width, 4.0 inches, on a 17-inch wheel, and the tire turns about 806 times per mile.
In flotation terms that is about 25.0x7.3R17. People often call it a 25-inch tire.
The size most often compared with it is 205/60R17, which is 1.7" taller (+6.7%). At an indicated 60 mph you would be doing 64.0 mph on it, more than the 3% change many shops use as a limit.
| Current | New | Difference |
|---|
| Shows | Actual speed |
|---|
Same 17" wheel, within 20 mm of width and 10 points of aspect ratio.
Sizes within 2% of 25.0" on 18" or 15" or 16" wheels.
| Size | Diameter | Width | Sidewall | vs 185/55R17 | |
|---|---|---|---|---|---|
| 255/35R18 | 25.0" | 10.0" | 3.5" | +0.1% | |
| 295/30R18 | 25.0" | 11.6" | 3.5" | −0.2% | |
| 215/60R15 | 25.2" | 8.5" | 5.1" | +0.6% | |
| 225/50R16 | 24.9" | 8.9" | 4.4" | −0.6% | |
| 305/30R18 | 25.2" | 12.0" | 3.6" | +0.8% | |
| 285/30R18 | 24.7" | 11.2" | 3.4" | −1.1% |
Actual speed when the speedometer is calibrated for 185/55R17.
| Speedometer shows | on 205/60R17 | on 205/65R17 |
|---|---|---|
| 30 mph | 32.0 mph | 33.0 mph |
| 45 mph | 48.0 mph | 49.5 mph |
| 60 mph | 64.0 mph | 65.9 mph |
| 70 mph | 74.7 mph | 76.9 mph |
25.0 inches (635 mm). The sidewall is 4.0 inches.
7.3 inches (185 mm) section width, measured sidewall to sidewall.
About 25.0x7.3R17.
205/60R17 is +6.7% in diameter, more than the common 3% guideline, so expect a speedometer error and check clearance. It is 0.8" wider.