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Sidewall

225/40R18

225 mm across the tread, a sidewall 40% of that — 90 mm — on a 18-inch rim. That puts the whole wheel at 25.1 inches tall.

90.0 mm sidewall637 mm · 25.1"
Sidewall
3.54"
90 mm
Overall
25.1"
637.2 mm
Circumference
78.8"
2.002 m
Revs per mile
804
per minute at 60 mph

What it needs to sit on

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It mounts on a rim between 6" and 8.5" wide, and the tread follows the rim: roughly 5 mm of section width for every half-inch, so about 213 mm across at the narrow end and 238 mm at the wide one. Written the way lift kits and wheel wells are, it is a 25.1×8.9R18 — tall by wide, in inches.

What goes wrong on this size

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39 drivers have filed a complaint. 1 of them ended in a crash, hurting 2 people. Nobody died.

36 of them name what let go, and it is most often crack. Bridgestone is named more than any other brand.

What let goComplaints
crack9
blowout8
blister7
road hazard6
tread separation4
puncture2
not stated3

Where the wheel is named, 31 of 33 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
205/45R1825.3" +0.7 %+2.3 mm60.4 mphside by side
215/40R1824.8" -1.3 %-4.0 mm59.2 mphside by side
235/40R1825.4" +1.3 %+4.0 mm60.8 mphside by side
245/35R1824.8" -1.3 %-4.3 mm59.2 mphside by side
215/45R1825.6" +2.1 %+6.8 mm61.3 mphside by side
235/35R1824.5" -2.4 %-7.8 mm58.5 mphside by side
205/40R1824.5" -2.5 %-8.0 mm58.5 mphside by side
245/40R1825.7" +2.5 %+8.0 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.


205/50R17103 mm sidewall — 14% more
195/40R1978 mm sidewall — 13% less
255/40R17102 mm sidewall — 13% more
255/30R1977 mm sidewall — 15% less
225/35R1979 mm sidewall — 13% less
225/45R17101 mm sidewall — 13% more

Tires graded in this size

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


TireTreadwearWet grip
Hankook KInERGy GT (OE)740A
Hankook veNtus S1 noble2 (OE)700A
JK TYRE UX ROYALE MAXX580A
CONTINENTAL ContiProContact540AA
CONTINENTAL ProContact GX540A
CONTINENTAL ProContact TX540A
Hankook KInERGy 4s (OE)540A
Granada GRANADA Touring HP520A
Americus Sport HP500A
Firestone AFFINITY AS500AA
Hankook Roadhandler UHP500A
Hankook veNtus S1 Noble2500AA

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
205/45R1830.2 mph50.4 mph70.5 mph10,071
215/40R1829.6 mph49.4 mph69.1 mph9,874
235/40R1830.4 mph50.6 mph70.9 mph10,126
245/35R1829.6 mph49.3 mph69.1 mph9,867
215/45R1830.6 mph51.1 mph71.5 mph10,212