255/45R17 tire size

A 255/45R17 tire is 26.04 inches (661.3 mm) tall, 10.04 in (255 mm) wide and fits a 17-inch wheel. In inch notation it is roughly a 26.0x10.0R17.

255/45R17 dimensions
Overall diameter	26.04 in	661.3 mm
Section width	10.04 in	255 mm
Sidewall height	4.52 in	114.8 mm
Circumference	81.79 in	2,078 mm
Revolutions	774.6 per mile	481.3 per km
Rim diameter	17 in	431.8 mm

Compare 255/45R17 with another size

Current size

New size

Speed in mphkm/h

Overall diameter difference

−0.23%

60 mph on the speedometer = 59.9 mph actual

Within the ±3 % diameter range most tire fitters accept.

Ground clearance: −0.8 mm (−0.03 in)
Revolutions: 775 → 776 per mile

255/45R17 285/40R17

Side-by-side dimensions

	Current	New	Difference	%
Diameter	26.04 in	25.98 in	−0.06 in	−0.23%
Diameter	661.3 mm	659.8 mm	−1.5 mm	−0.23%
Width	10.04 in	11.22 in	+1.18 in	+11.76%
Width	255.0 mm	285.0 mm	+30.0 mm	+11.76%
Sidewall	4.52 in	4.49 in	−0.03 in	−0.65%
Sidewall	114.8 mm	114.0 mm	−0.8 mm	−0.65%
Circumference	81.79 in	81.61 in	−0.19 in	−0.23%
Revs per mile	774.6	776.4	+1.8	+0.23%

Speedometer error

Speedometer shows	Actual speed	Difference
20 mph	20.0 mph	0.0 mph
30 mph	29.9 mph	−0.1 mph
40 mph	39.9 mph	−0.1 mph
50 mph	49.9 mph	−0.1 mph
60 mph	59.9 mph	−0.1 mph
70 mph	69.8 mph	−0.2 mph
80 mph	79.8 mph	−0.2 mph

Alternative sizes on the same 17-inch wheel

Sizes in use within ±3 % of the overall diameter of 255/45R17:

Plus and minus sizes for 255/45R17

Size	Wheel	Diameter	Difference
225/60R15	Minus 2 (15 in)	25.63 in	−1.56%
225/55R16	Minus 1 (16 in)	25.74 in	−1.12%
245/50R16	Minus 1 (16 in)	25.65 in	−1.50%
245/55R16	Minus 1 (16 in)	26.61 in	+2.21%
225/60R16	Minus 1 (16 in)	26.63 in	+2.28%
255/40R18	Plus 1 (18 in)	26.03 in	−0.02%
225/45R18	Plus 1 (18 in)	25.97 in	−0.24%
295/35R18	Plus 1 (18 in)	26.13 in	+0.36%
285/35R18	Plus 1 (18 in)	25.85 in	−0.70%
255/35R19	Plus 2 (19 in)	26.03 in	−0.03%
225/40R19	Plus 2 (19 in)	26.09 in	+0.20%
295/30R19	Plus 2 (19 in)	25.97 in	−0.26%
305/30R19	Plus 2 (19 in)	26.20 in	+0.65%
255/30R20	Plus 3 (20 in)	26.02 in	−0.05%
225/35R20	Plus 3 (20 in)	26.20 in	+0.64%
265/30R20	Plus 3 (20 in)	26.26 in	+0.86%
245/30R20	Plus 3 (20 in)	25.79 in	−0.95%

Vehicles approved with 255/45R17 tires

Models whose Swiss type approval lists 255/45R17 as a standard or optional size (187 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 17-inch sizes

Reading the 255/45R17 size

255 — section width in millimetres (10.04 in).
45 — aspect ratio: the sidewall is 45 % of the width, 114.8 mm.
R — radial construction (ZR on the sidewall means a high-speed rated radial; the dimensions are the same).
17 — fits a 17-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.