How Big Are 265/70R18 Tires? | True Dimensions & Fit Guide

Knowing the exact dimensions of a 265/70R18 tire matters when you’re checking clearance, lifting a truck, or comparing options side-by-side. The numbers in the size tell a story: 265 millimeters of section width, a 70 percent sidewall height, radial construction, and an 18-inch rim diameter. But the published specs aren’t always the whole picture.

The Short Breakdown: What The Numbers Mean

The size designation decodes like this: 265 refers to the tire’s section width in millimeters (roughly 10.4 inches), and 70 is the aspect ratio, meaning the sidewall height equals 70 percent of the width. The R stands for radial construction, and 18 is the wheel diameter in inches.

Those two numbers combine to produce the overall height.

Published Specs: How The Brands Stated Their Numbers

Here’s the detail that surprises most buyers: the dimensions printed on the sidewall and in the spec sheets vary by manufacturer, and sometimes by compound.

None of them are exactly identical in weight, tread depth, or revolutions per mile, because each brand engineers its own construction.

Fitment Caveats: What The Size Doesn’t Tell You

An 18-inch rim is the anchor, and a 7.0 to 9.0 inch rim width is the safe mounting range. But fitment goes beyond rim match. Some versions come as LT tires with heavier construction and different load capacities.

The load index and speed rating matter more than the height for safety. A standard load (SL) tire and an LT tire in the same size will have different max pressures, carrying capacities, and sometimes different overall diameters when mounted. Matching the tire’s ratings to your vehicle’s requirements is non-negotiable.

Published dimensions are nominal. Actual mounted size can shift slightly based on the rim width used and the tire’s design.

If you’re comparing options and want to see tested models side-by-side, our roundup of the best 265/70R18 tires breaks down the top performers by load rating, tread depth, and value.

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