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Sidewall

235/50R18

235 mm across the tread, a sidewall 50% of that — 118 mm — on a 18-inch rim. That puts the whole wheel at 27.3 inches tall.

118 mm sidewall692 mm · 27.3"
Sidewall
4.63"
118 mm
Overall
27.3"
692.2 mm
Circumference
85.6"
2.175 m
Revs per mile
740
per minute at 60 mph

What it needs to sit on

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It mounts on a rim between 6.5" and 8.5" wide, and the tread follows the rim: roughly 5 mm of section width for every half-inch, so about 225 mm across at the narrow end and 245 mm at the wide one. Written the way lift kits and wheel wells are, it is a 27.3×9.3R18 — tall by wide, in inches.

What goes wrong on this size

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

20 of them name what let go, and it is most often tread separation. Dunlop is named more than any other brand.

What let goComplaints
tread separation11
blowout5
road hazard2
crack2
not stated5

Where the wheel is named, 15 of 19 were on the front — the end that steers.

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
215/55R1827.3" +0.2 %+0.8 mm60.1 mphside by side
255/45R1827.0" -0.8 %-2.8 mm59.5 mphside by side
225/50R1826.9" -1.4 %-5.0 mm59.1 mphside by side
245/50R1827.6" +1.4 %+5.0 mm60.9 mphside by side
225/55R1827.7" +1.8 %+6.3 mm61.1 mphside by side
245/45R1826.7" -2.1 %-7.3 mm58.7 mphside by side
215/50R1826.5" -2.9 %-10.0 mm58.3 mphside by side
255/50R1828.0" +2.9 %+10.0 mm61.7 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.


235/45R19106 mm sidewall — 10% less
235/55R17129 mm sidewall — 10% more
265/40R19106 mm sidewall — 10% less
215/60R17129 mm sidewall — 10% more
265/50R17133 mm sidewall — 13% more
205/50R19103 mm sidewall — 13% less

Tires graded in this size

Longest-lasting tread first. The grade is set by the maker and checked by regulators.


TireTreadwearWet grip
CONTINENTAL ContiProContact540AA
CONTINENTAL ProContact RX540A
CONTINENTAL ProContact TX540A
PARAGON SCORPION ZERO ASIMMETRICO520A
Goodride SA07460A
GENERAL TIRE G-MAX Justice440AA
Hankook Optimo H426440A
Sears Enhance L/X (V-Rated)440A
Sonar TOUR PLUS LSV440A
CONTINENTAL ContiSportContact 5420AA
Panther SCORPION STR400A
Vredestein ADVAN S.T.320AA

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
215/55R1830.1 mph50.1 mph70.2 mph10,022
255/45R1829.8 mph49.6 mph69.4 mph9,921
225/50R1829.6 mph49.3 mph69.0 mph9,856
245/50R1830.4 mph50.7 mph71.0 mph10,144
225/55R1830.5 mph50.9 mph71.3 mph10,181