255/45R18 tire size
A 255/45R18 tire stands 27.0 inches tall and 10.0 inches wide, with a 4.5-inch sidewall on an 18-inch rim.
- Overall height
- 27.0 in687 mm
- Section width
- 10.0 in255 mm
- Sidewall height
- 4.5 in115 mm
- Rim diameter
- 18 in457 mm
- Circumference
- 84.9 in2157 mm
- Revolutions per mile
- 746464 per km
- Inch size
- 27.0x10.0R18
Compare it with any other size in the tire size calculator.
Sizes you can swap to
These 18-inch sizes are within two width steps and 3% of a 255/45R18's overall height, the usual limit before the speedometer, ABS and transmission notice. The closest is 235/50R18, 0.8% taller (0.22 in). Wider sizes also need room in the wheel well and a rim width that suits them.
Plus and minus sizes
Changing rim size means changing the sidewall to keep the same overall height. On 16-inch or 17-inch or 19-inch or 20-inch rims, these are the closest matches to a 255/45R18.
Other 18-inch sizes near 255/45R18
255 mm wide, other sidewalls
45 series, other widths
See the other sizes for this rim on 18-inch tire sizes.
Shop 255/45R18 tires
These open each store's own list of 255/45R18 tires, where you can filter by type, load and speed rating.
255/45R18 questions
How tall is a 255/45R18 tire?
About 27.0 inches (687 mm) from the ground to the top of the tread, unloaded. On the vehicle, carrying weight, it sits a little lower.
What does 255/45R18 mean?
255 is the section width in millimetres (10.0 in). 45 means the sidewall is 45% of that width: 115 mm, or 4.5 in. R means radial construction, and 18 is the rim diameter in inches.
Can I use 235/50R18 instead of 255/45R18?
235/50R18 is 0.8% taller (0.22 in) and 20 mm narrower, which is inside the usual 3% rule. With it fitted, the speedometer shows 60 mph when you are doing 60.5 mph.
What is 255/45R18 in inches?
In inch terms it is 27.0x10.0R18: 27.0 inches tall, 10.0 inches wide, for an 18-inch rim.
How many revolutions per mile does a 255/45R18 make?
About 746 turns per mile, worked out from its unloaded circumference of 84.9 inches. Makers list slightly higher numbers for their own tires, because a loaded tire rolls on a smaller radius.