40x13.50R17 — the largest size in this catalogue
Forty inches of tire, seventeen inches of wheel, and the highest proportion of casing on the site.
Flotation (imperial) notation · Flotation (imperial)
- Overall diameter
- 40.00 in
- 1016 mm
- Section width
- 13.50 in
- 343 mm
- Sidewall height
- 11.50 in
- 292 mm
- Aspect ratio
- 85.2%
- sidewall as a share of width
- Wheel diameter
- 17 in
- the hole in the middle
- Circumference
- 125.7 in
- 3192 mm
- Revolutions per mile
- 504.2
- geometric, not measured
- Revolutions per km
- 313.3
- 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
- 315/70R1734.36 in tall-5.64 in
- 305/70R1733.81 in tall-6.19 in
- 295/70R1733.26 in tall-6.74 in
Compare any two sizes, including ones this site has no page for, in the comparison tool.
No vehicle record here lists 40x13.50R17. It is the biggest tire in the catalogue by every dimension: tallest, joint widest, deepest casing, and the fewest revolutions per mile at 504.2.
More sidewall than wheel
11.50 in above the rim on each side, against a 17-inch wheel. Twenty-three of this tire's forty inches of diameter are rubber.
Work the proportion the way a metric code would and it comes to 85 — the same number that 235/85R16 prints on its sidewall and the highest aspect ratio anywhere on this site. The difference is that the metric size announces it and this one does not, because flotation codes carry no aspect field at all.
That is the quiet consequence of the notation. The tallest-profile tire in the catalogue and the narrowest-looking one are shaped alike in proportion, and only one of them says so.
The 17-inch wheel, from the top
| Size | Diameter | Against 40x13.50R17 | Section width |
|---|---|---|---|
| 40x13.50R17 | 40.00 in | — | 13.50 in |
| 37x12.50R17 | 37.00 in | −3.00 in (7.50%) | 12.50 in |
| 37x13.50R17 | 37.00 in | −3.00 in (7.50%) | 13.50 in |
| 35x11.50R17 | 35.00 in | −5.00 in (12.50%) | 11.50 in |
| 35x12.50R17 | 35.00 in | −5.00 in (12.50%) | 12.50 in |
| 315/70R17 | 34.36 in | −5.64 in (14.09%) | 12.40 in |
Three inches to the nearest thing below it, and that is the smallest gap available. Everything else on the wheel is at least five inches down.
What the numbers do at this scale
Against a 37x12.50R17, an indicated 70 mph on the smaller tire's calibration is an actual 75.7 mph once these are fitted, and a hundred indicated miles is 108.1. Against 315/70R17 the same figures are 81.5 mph and 116.4 miles. The two sizes are set side by side in a direct comparison.
Percentages that large stop being an instrument problem and become a driveline one. A wheel turning 504.2 times in a mile instead of 586.9 asks the whole drivetrain to spin proportionally slower at any road speed, and what a ratio change would have to do about it is worked through in the axle ratio basics reference.
Related
- 37x12.50R17 vs 40x13.50R17
- 315/70R1734.36 in tall
- 305/70R1733.81 in tall
- 295/70R1733.26 in tall
Class: Flotation (imperial). Every figure above is computed from the size code, not stored — see how these numbers are calculated.