31x10.50R16 — the same 31, half an inch less casing
Two codes that differ by one character and by nothing a speedometer can detect.
Flotation (imperial) notation · Flotation (imperial)
- Overall diameter
- 31.00 in
- 787 mm
- Section width
- 10.50 in
- 267 mm
- Sidewall height
- 7.50 in
- 191 mm
- Aspect ratio
- 71.4%
- sidewall as a share of width
- Wheel diameter
- 16 in
- the hole in the middle
- Circumference
- 97.4 in
- 2474 mm
- Revolutions per mile
- 650.6
- geometric, not measured
- Revolutions per km
- 404.3
- 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
- 265/70R1630.61 in tall-0.39 in
- 245/75R1630.47 in tall-0.53 in
- 265/75R1631.65 in tall+0.65 in
Compare any two sizes, including ones this site has no page for, in the comparison tool.
No vehicle in this catalogue is recorded on 31x10.50R16. It is a replacement size for 16-inch wheels on vehicles whose owners want the 31-inch height without going back to a 15.
One character apart
| 31x10.50R15 | 31x10.50R16 | |
|---|---|---|
| Overall diameter | 31.00 in | 31.00 in |
| Section width | 10.50 in | 10.50 in |
| Sidewall | 8.00 in | 7.50 in |
| Circumference | 97.4 in | 97.4 in |
| Revolutions per mile | 650.6 | 650.6 |
A flotation code states its outside diameter outright, so two members of the same family cannot disagree about height however different their wheels are. Circumference follows from diameter and revolutions per mile follows from circumference, which is why the bottom three rows are identical rather than merely close.
The half inch of casing is the whole difference between them, and it is entirely a consequence of the inch of wheel. Tread width does not move. Standing height does not move. Nothing a driver could measure from the outside moves except how much of the assembly is rubber.
Three flotation sizes share this wheel
The 16-inch wheel carries the sparsest imperial range in the catalogue: this size, 33x12.50R16 and 35x12.50R16. The steps between them are 2.00 in each, and the width jumps 2.00 in at the first step and not at all at the second.
That is a much coarser ladder than the 15-inch wheel offers, where five codes climb in single inches. The 16 was never the enthusiast wheel the 15 was, so the sizes built for it were the ones a factory truck market asked for.
Its metric shadow
265/70R16 measures 30.61 in on 10.43 in of section. Against this size that is 0.39 in shorter and seven hundredths of an inch narrower — as near as a metric code gets to this tread width on this wheel.
265/75R16 goes the other way at 31.65 in, 0.65 in taller on the same 10.43 in. So the metric options bracket this size within two thirds of an inch in either direction while matching its width almost exactly, which makes the choice between the three a decision about height alone. The metric versus imperial reference covers how the two notations describe the same tire differently.
Related
Class: Flotation (imperial). Every figure above is computed from the size code, not stored — see how these numbers are calculated.