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Sidewall

205/50R18

205 mm across the tread, a sidewall 50% of that — 103 mm — on a 18-inch rim. That puts the whole wheel at 26.1 inches tall.

103 mm sidewall662 mm · 26.1"
Sidewall
4.04"
103 mm
Overall
26.1"
662.2 mm
Circumference
81.9"
2.080 m
Revs per mile
774
per minute at 60 mph

What it needs to sit on

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It mounts on a rim between 5.5" and 7.5" wide, and the tread follows the rim: roughly 5 mm of section width for every half-inch, so about 195 mm across at the narrow end and 215 mm at the wide one. Written the way lift kits and wheel wells are, it is a 26.1×8.1R18 — tall by wide, in inches.

What goes wrong on this size

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2 drivers have filed a complaint. 0 of them ended in a crash, and nobody was hurt. Nobody died.

2 of them name what let go, and it is most often crack.

What let goComplaints
crack2

Where the wheel is named, 2 of 2 were on the rear, and 0 on the front.

What fits instead

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Same 18-inch rim, height within 3%. Past that the speedometer starts lying and things begin to rub.


SizeHeightRide heightSpeedo reads 60, you doCompare
185/55R1826.0" -0.2 %-0.8 mm59.9 mphside by side
225/45R1826.0" -0.4 %-1.3 mm59.8 mphside by side
195/55R1826.4" +1.4 %+4.8 mm60.9 mphside by side
195/50R1825.7" -1.5 %-5.0 mm59.1 mphside by side
215/50R1826.5" +1.5 %+5.0 mm60.9 mphside by side
215/45R1825.6" -1.7 %-5.8 mm59.0 mphside by side
185/60R1826.7" +2.6 %+8.5 mm61.5 mphside by side

Same height, different rim

Bigger rim, same overall height. Sharper steering, harsher ride, and far less rubber between your wheel and the next pothole.


225/40R1990 mm sidewall — 12% less
175/65R17114 mm sidewall — 11% more
195/60R17117 mm sidewall — 14% more
195/45R1988 mm sidewall — 14% less
235/50R17118 mm sidewall — 15% more
205/45R1992 mm sidewall — 10% less

If you fit something taller

A taller tire covers more ground per turn, so the needle reads low and the odometer counts short. Over ten thousand miles on the dial, the last column is what you really drove.


Fitted insteadReads 30Reads 50Reads 70Real miles per 10,000 shown
185/55R1829.9 mph49.9 mph69.8 mph9,977
225/45R1829.9 mph49.8 mph69.7 mph9,962
195/55R1830.4 mph50.7 mph71.0 mph10,143
195/50R1829.5 mph49.2 mph68.9 mph9,849
215/50R1830.5 mph50.8 mph71.1 mph10,151