SidewallerTire & wheel calculators

205/60R16 vs 245/40R18

245/40R18 is 0.1% taller (+0.03 in) and 1.57 in wider than 205/60R16.

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Close match

245/40R18 is 0.1% taller than 205/60R16. That is inside the ±3% most shops treat as a straight swap.

205/60R16245/40R18Change
Diameter25.69″25.72″+0.03″+0.1%
Width8.07″9.65″+1.57″+19.5%
Sidewall4.84″3.86″−0.98″−20.3%
Circumference80.7″80.8″+0.1″+0.1%
Wheel16″18″+2″
Revs per mile785784−1
SideTread
205/60R16245/40R18
Speedometer shows 60 mph60.1mph

Real speed on 245/40R18.

Ground clearance+0.02in

Change in height under the axle.

Width per side+0.79in

On the same wheel, split inboard and outboard.

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205/60R16 or 245/40R18?

Can I use 245/40R18 instead of 205/60R16?

245/40R18 is 0.1% taller than 205/60R16. 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 245/40R18 you are really doing 60.1 mph if the speedometer was set up for 205/60R16. Going the other way, 205/60R16 would make it read 59.9 mph at a real 60.

How much ground clearance does it change?

Half the diameter difference: +0.02 in (+0 mm) under the axle.

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