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Tire sizes

33x12.50R16 — the widest thing a 16-inch wheel takes

One wheel diameter, ten and a half inches of tire height, and the two extremes of what it can be asked to carry.

Flotation (imperial) notation · Flotation (imperial)

Overall diameter
33.00 in
838 mm
Section width
12.50 in
318 mm
Sidewall height
8.50 in
216 mm
Aspect ratio
68.0%
sidewall as a share of width
Wheel diameter
16 in
the hole in the middle
Circumference
103.7 in
2633 mm
Revolutions per mile
611.2
geometric, not measured
Revolutions per km
379.8
geometric, not measured
Typical load index
108–128
2205–3968 lb per tire

Flotation sizes are almost always LT construction, so they share the light-truck band. Speed symbols run low because the aggressive tread patterns these sizes are sold in are rated against heat build-up, not against sustained high speed.

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 metric notation, same wheel

  • 285/75R1632.83 in tall-0.17 in
  • 235/85R1631.73 in tall-1.27 in
  • 265/75R1631.65 in tall-1.35 in

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

The second-generation Toyota Tacoma and the Nissan Frontier D40 both list 33x12.50R16 among their common upgrades. No vehicle here ships it.

The two extremes of a 16-inch wheel

Set this size against 235/85R16, the tall-narrow code that occupies roughly the same part of the 16-inch range:

235/85R16 33x12.50R16
Overall diameter 31.73 in 33.00 in
Section width 9.25 in 12.50 in
Sidewall 7.86 in 8.50 in
Revolutions per mile 635.6 611.2

1.27 in of height separates them and 3.25 in of width does. That width gap is the largest between any two sizes on a 16-inch wheel that are within a foot of each other in circumference, and it is the clearest statement of how differently the same wheel can be used.

One of those tires is specified for ambulances and utility bodies that need to put weight on a narrow footprint. The other is bought to fill an arch.

Above and below on the same wheel

Seventeen sizes share the 16-inch wheel here, running from 195/55R16 at 24.44 in to 35x12.50R16 at 35.00 in — 10.56 in of range. This size sits second from the top.

Below it, 285/75R16 is 0.17 in shorter and 1.28 in narrower, which is as close as the metric range gets. Below that the drop is abrupt: 265/75R16 at 31.65 in is 1.35 in down, and the factory sizes these two trucks actually wear are between 2.53 in and 2.94 in down.

What the step costs the trucks that list it

From 245/75R16 at 30.47 in the change is 2.53 in. Divided by that starting diameter it is 8.31%, so 70 mph on the dial is 75.8 mph on the road and a hundred recorded miles are 108.3 travelled.

From 265/70R16 at 30.61 in it is 2.39 in and 7.82%: 75.5 mph and 107.8 miles. Both are large enough that every distance-derived figure the vehicle reports moves with them, and the speedometer calibration reference sets out which readings inherit the error.

Related

Class: Flotation (imperial). Every figure above is computed from the size code, not stored — see how these numbers are calculated.