TruckTally

325/60R18 tire size

325mm wide with a 60% aspect ratio on a 18-inch wheel — 33.4 inches tall overall. Below: what it measures, what it swaps with, and which trucks run it from the factory.

Overall diameter
33.35"
Section width
12.80"
325mm
Sidewall height
7.68"
Revs per mile
605
104.8" circumference

Sizes that swap with 325/60R18

Within 3% of the original diameter — close enough to fit without a recalibration or clearance work on most trucks.

SizeDiameterDifferenceWidth
295/70R1733.26"-0.09" (-0.3%)11.6"
285/60R2033.46"+0.11" (+0.3%)11.2"
285/50R2233.22"-0.13" (-0.4%)11.2"
305/55R2033.21"-0.15" (-0.4%)12.0"
275/70R1833.16"-0.20" (-0.6%)10.8"
295/65R1833.10"-0.26" (-0.8%)11.6"
305/65R1833.61"+0.26" (+0.8%)12.0"
275/65R1933.07"-0.28" (-0.8%)10.8"

Plus and minus sizing

Same overall height on a different wheel. Going down a wheel size buys sidewall for off-road; going up is usually about looks. Gearing and speedometer stay put either way.

Compare 325/60R18 against your current size

Tire size comparison

Diameter change, speedometer error, and whether it will rub.

Current / stock size

33.4" tall · 12.8" wide ·

New size

33.3" tall · 11.6" wide ·

Direct fit

Diameter and width are close enough to stock that this is a bolt-on swap on an unmodified truck.

18"33.4" tall325/60R1817"33.3" tall295/70R1712.8" wide11.6" wide
Drawn to scale from the calculated sizes. Circles compare overall height and wheel diameter; the bars underneath compare section width.
Diameter change
-0.09"
-0.3% — 33.35" to 33.26"
Speedometer at 70
69.8mph actual
Reads 0.3% fast — you are going slower than it says.
Ride height
-0.05"
Change at the axle, before any lift or leveling kit.
Section width
-1.18"
12.80" to 11.61"
Revs per mile
606
+2 vs. stock (605)
Odometer drift
997real miles
Actual distance covered per 1,000 miles shown on the odometer.
  • Sits 0.05" lower at the axle.
  • Within the range normally treated as a direct swap — no clearance work expected.

Reading this size

325/60R18 breaks down as 325mm section width, an aspect ratio of 60 (the sidewall is 60% of the width, so 7.68 inches), and a 18-inch wheel. Overall diameter is the wheel plus two sidewalls: 18 + 7.68 + 7.68 = 33.35 inches.

That last figure is the one that matters when you change size. The speedometer, odometer, transmission shift points and stability control all assume the factory diameter, so staying within a few percent keeps everything calibrated. Width matters for clearance rather than gearing — it decides whether the tire touches the suspension at full lock.

Common questions

How tall is a 325/60R18 tire?

33.35 inches in overall diameter, with a 7.68-inch sidewall on a 18-inch wheel. Section width is 12.80 inches (325mm), and it turns about 605 times per mile. Real tires vary from the nominal figure by up to half an inch depending on brand and tread.

What is equivalent to a 325/60R18?

The closest common size is 295/70R17 at 33.26 inches — -0.3% different. Anything within about 3% of the original diameter swaps on without upsetting the speedometer badly or needing a tune.

Will 325/60R18 fit my truck?

We do not have it listed as a factory size on the trucks we cover, so treat it as an upgrade size. Put your current size into the calculator on this page to see the diameter change and whether it is likely to rub.

Does going to 325/60R18 affect my speedometer?

Only if the overall diameter changes. The speedometer counts wheel rotations and multiplies by the factory tire circumference, so a larger tire makes the truck travel further per rotation than the gauge assumes and the display reads low. Around 3% is where transmission shift points and stability control calibration start to matter, and most modern trucks can be recalibrated for the new size.

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