SidewallerTire & wheel calculators

225/40R18 vs 215/45R18

215/45R18 is 2.1% taller (+0.53 in) and 0.39 in narrower than 225/40R18.

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Close match

215/45R18 is 2.1% taller than 225/40R18. That is inside the ±3% most shops treat as a straight swap.

225/40R18215/45R18Change
Diameter25.09″25.62″+0.53″+2.1%
Width8.86″8.46″−0.39″−4.4%
Sidewall3.54″3.81″+0.27″+7.5%
Circumference78.8″80.5″+1.7″+2.1%
Wheel18″18″Same
Revs per mile804787−17
SideTread
225/40R18215/45R18
Speedometer shows 60 mph61.3mph

Real speed on 215/45R18.

Ground clearance+0.27in

Change in height under the axle.

Width per side−0.20in

On the same wheel, split inboard and outboard.

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225/40R18 or 215/45R18?

Can I use 215/45R18 instead of 225/40R18?

215/45R18 is 2.1% taller than 225/40R18. That is inside the ±3% most shops treat as a straight swap. Also match or beat the original load index and speed rating, and check that the wheel width suits the new tire.

Will my speedometer be off?

At an indicated 60 mph on 215/45R18 you are really doing 61.3 mph if the speedometer was set up for 225/40R18. Going the other way, 225/40R18 would make it read 58.8 mph at a real 60.

How much ground clearance does it change?

Half the diameter difference: +0.27 in (+7 mm) under the axle.

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