How Tall Are 255/75R17 Tires? | Diameter, Width & Specs

255/75R17 tires measure 32.1 inches tall (about 32 inches) with a 10.0-inch section width, fitted to a 17-inch wheel.

The answer to how tall 255/75R17 tires are comes down to the metric sizing system: the 255 is the section width in millimeters, the 75 is the aspect ratio (sidewall height as a percentage of width), and the R17 tells you it fits a 17-inch rim. That combination lands at a 32.1-inch overall diameter, which is why these tires are often referred to as 32-inch tires in the off-road community.

Full 255/75R17 Spec Breakdown

These figures are consistent across tire-size databases, though individual brands can vary slightly by tenths of an inch. The table below gives you the complete dimensional picture so you can check fitment against your truck or SUV before you buy.

The sidewall height matters almost as much as the overall diameter. Because the 75-series aspect ratio means the sidewall is 75% of 255 mm, you get a tall, flexible sidewall that absorbs trail impacts well—a key reason this size is popular on trucks and SUVs that see dirt duty.

Real Tires vs. The Math

No two tire models measure exactly the same even when the size label matches. The tire-size database shows that a BFGoodrich Mud-Terrain T/A KM in LT255/75R17 comes in at 32.1 inches tall, while a Goodyear Wrangler SR-A in P255/75R17 also measures 32.1 inches—but those two tires differ substantially in weight, load range, tread depth, and intended use.

That distinction matters: the LT (light truck) construction uses a stronger casing, carries a higher load rating, and typically weighs more, while the P (passenger) version rides smoother and lighter. The 255/75R17 tire-size reference from TireSize.com lists both construction types and confirms that overall diameter can shift by a few tenths of an inch between brands.

You should also check your vehicle’s owner’s manual or door jamb sticker for the exact rim width your truck was designed for. A tire’s measured rim is usually 7.0 inches for this size, but the safe mounting range goes from 6.5 to 8.5 inches, so wheels at either end of that range can work depending on the tire model.

Why 32 Inches?

The 32.1-inch overall diameter is exactly why this tire size is so common. It fits many half-ton trucks and SUVs without a lift kit, clears fenders without rubbing at stock ride height, and still gives you enough ground clearance for moderate off-road use. The 629 revolutions per mile also keeps speedometer readings accurate on vehicles that came from the factory with similar-diameter tires.

The circumference of roughly 100.5 inches is the number to use when calculating gearing changes or when comparing this size against taller 33-inch or 34-inch options. If you are shopping for replacements, our tested roundup of the best 255/75R17 tire options compares the leading models on the market today.

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