35x12.50R18 — the middle rung of the tidiest imperial ladder
Three sizes, one width, even steps — and one metric code that very nearly joins them.
Flotation (imperial) notation · Flotation (imperial)
- Overall diameter
- 35.00 in
- 889 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
- 18 in
- the hole in the middle
- Circumference
- 110.0 in
- 2793 mm
- Revolutions per mile
- 576.2
- geometric, not measured
- Revolutions per km
- 358.1
- 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
- 285/75R1834.83 in tall-0.17 in
- 285/70R1833.71 in tall-1.29 in
- 275/70R1833.16 in tall-1.84 in
Compare any two sizes, including ones this site has no page for, in the comparison tool.
Platforms recorded with this size
The second-generation Toyota Tundra lists 35x12.50R18 among its common upgrades, and it is the only vehicle record here that does.
The ladder, and where this sits on it
33x12.50R18 at 33.00 in, this size at 35.00 in, 37x12.50R18 at 37.00 in. One width throughout, two-inch steps, and a sidewall that grows by exactly half an inch per side at each rung — 7.50 in, 8.50 in, 9.50 in.
As percentages the steps shrink as the ladder climbs: 6.06% from the 33 to here, 5.71% from here to the 37. Same two inches, larger denominator.
Of the three, only the bottom rung and this one appear on any vehicle's list in this catalogue. The 37 at the top of the ladder is recorded nowhere, which puts the practical ceiling of the 18-inch imperial range at this size rather than at the largest one built for the wheel.
What the 18-inch wheel offers instead
| Size | Diameter | Against 35x12.50R18 | Section width |
|---|---|---|---|
| 275/65R18 | 32.07 in | −2.93 in (8.36%) | 10.83 in |
| 285/65R18 | 32.59 in | −2.41 in | 11.22 in |
| 33x12.50R18 | 33.00 in | −2.00 in | 12.50 in |
| 275/70R18 | 33.16 in | −1.84 in | 10.83 in |
| 285/70R18 | 33.71 in | −1.29 in | 11.22 in |
| 285/75R18 | 34.83 in | −0.17 in (0.48%) | 11.22 in |
| 35x12.50R18 | 35.00 in | — | 12.50 in |
The bottom two rows are the pairing that matters. 285/75R18 comes within 0.17 in of this size — half a per cent — and does it on a casing 1.28 in narrower. A truck fitted with one and offered the other is being offered an inch and a quarter of stance and nothing else the arithmetic can see.
Coming from the Tundra's factory fitment
The second-generation Tundra is recorded on 275/65R18 among other sizes, so reaching this one is 2.93 in, which against that starting diameter is 9.12%. The dial reading 70 mph corresponds to 76.4 mph, and a hundred recorded miles to 109.1.
At that scale the driveline is as affected as the dial. The wheel now turns 576.2 times in a mile instead of 628.8, so at any given road speed everything upstream of it — driveshaft, transmission output, engine — is turning proportionally slower. The transmission gear ratios reference sets out where the tire sits in that chain.
Related
Class: Flotation (imperial). Every figure above is computed from the size code, not stored — see how these numbers are calculated.