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Tire sizes

265/65R18 — General Motors' half-ton 18, and the Tacoma's

Four platforms, two of them from the same manufacturer, and a near-twin one wheel size down.

Metric notation · Crossover and SUV

Overall diameter
31.56 in
802 mm
Section width
10.43 in
265 mm
Sidewall height
6.78 in
172 mm
Aspect ratio
65%
sidewall as a share of width
Wheel diameter
18 in
the hole in the middle
Circumference
99.2 in
2519 mm
Revolutions per mile
639.0
geometric, not measured
Revolutions per km
397.0
geometric, not measured
Typical load index
98–116
1653–2756 lb per tire

Crossovers are heavier than the cars they share size families with, so the same nominal size is produced at a higher index for SUV fitment than for passenger fitment. Two tires wearing the same size code can carry materially different loads.

The load-index range shown is the band this CLASS of size is typically produced in — not a list of what is in stock for this exact size today. Load index and speed symbol are printed on the sidewall of the specific tire you are holding, and the required minimum is on the placard of the specific vehicle you are fitting. Read both.

Nearest real sizes in imperial notation, same wheel

  • 33x12.50R1833.00 in tall+1.44 in
  • 35x12.50R1835.00 in tall+3.44 in
  • 37x12.50R1837.00 in tall+5.44 in

Compare any two sizes, including ones this site has no page for, in the comparison tool.

Platforms recorded with this size

Four vehicles here ship 265/65R18 — two consecutive generations of one full-size pickup, its badge-engineered sibling, and a mid-size import. A three-row crossover lists it as an upgrade instead. The panel above names all five.

Four hundredths from a 17-inch size

265/70R17 measures 31.61 in. The difference is 0.04 in, or 0.14%. Section width is identical at 10.43 in, because the first number in the code is the same and nothing else touches it.

What differs is where the height comes from: 6.78 in of sidewall here against 7.30 in on the 17-inch version, with the missing half inch per side accounted for by the larger wheel. Both are factory sizes on the fourth-generation Silverado, which offers 265/70R17 and 265/65R18 on adjacent trim levels.

The 18-inch band around it

Size Diameter Difference Section width
265/60R18 30.52 in −1.04 in 10.43 in
255/65R18 31.05 in −0.51 in 10.04 in
285/60R18 31.46 in −0.10 in 11.22 in
265/65R18 31.56 in — 10.43 in
255/70R18 32.06 in +0.49 in 10.04 in
275/65R18 32.07 in +0.51 in 10.83 in
285/65R18 32.59 in +1.02 in 11.22 in

285/60R18 is the row to notice: a tenth of an inch shorter and 0.79 in wider, which is as close to a pure width change as this wheel offers. 255/70R18 and 275/65R18 are the mirror image of each other around it — one 0.49 in taller and 0.39 in narrower, the other 0.51 in taller and 0.39 in wider, and the two of them 0.02 in apart.

What it replaces on the trucks that ship it

The fourth-generation Tacoma's other factory sizes are 245/75R17 at 31.47 in and 265/70R17 at 31.61 in, so on that vehicle this size sits between them with 0.14 in of total spread across all three. On the third-generation Silverado the comparison is wider: its 275/55R20 stands 31.91 in and its 255/70R17 stands 31.06 in.

Going to imperial notation means 33x12.50R18 at 33.00 in — a step of 1.44 in and 4.55%, taking an indicated 70 mph to an actual 73.2 mph. What the two notations measure, and why they are not directly comparable number for number, is covered in the metric versus imperial reference.

Related

Class: Crossover and SUV. Every figure above is computed from the size code, not stored — see how these numbers are calculated.