Ford Ranger (T6, North America): three factory sizes inside half an inch

Three sizes, half an inch apart

255/70R16 computes to 30.06 in, 265/60R18 to 30.52 in and 265/65R17 to 30.56 in. The whole factory range fits inside 0.51 in — 1.69% — with the 16-inch fitment the shortest of the three and the 17 and 18-inch fitments within 0.04 in of each other.

Ford held rolling diameter almost constant while the wheel grew two inches and the sidewall shrank to compensate. The consequence is that the trim you have barely affects your starting point, and every calculation below applies to all three within a rounding error.

Small tires make percentages large

This is the thing that separates a midsize truck's tire arithmetic from a full-size one's. The Ranger's starting diameter is around 30.5 in where a half-ton pickup's is around 32. Fit the same absolute increase and the percentage — which is what the speedometer, the odometer and the effective final drive all respond to — is bigger here.

33x10.50R17 at 33.00 in from 265/65R17 is +2.44 in, and that is a 7.97% change. An indicated 70 mph is 75.6 mph, and 100 miles on the odometer is 108.0 actually covered. Bolt a tire of the same nominal size onto a truck starting at 32 inches and the same 33 is a 3% change.

From the 16-inch 255/70R16 it is larger again: +2.94 in and 9.80%.

The narrow route and the wide route

The three sizes owners commonly step to on this platform separate cleanly by width:

• 265/70R17 at 31.61 in — +1.04 in from 265/65R17, and exactly zero change in section width. Same 265 mm casing, five more points of aspect ratio, nothing added across.
• 33x10.50R17 at 33.00 in — +2.44 in of height for 0.07 in of width. Nearly two and a half inches taller and, for practical purposes, no wider.
• 285/70R17 at 32.71 in — +2.15 in of height and +0.79 in of width, the conventional wider-and-taller move.

For a platform whose front-end packaging is tighter than a full-size truck's, that first option is the one that gets overlooked. It is a pure single-variable change: height moves, width does not, and the speedometer error is a manageable 3.41%.

The ratio column, and a sourcing trap specific to this truck

The ratio field is blank, and this platform is the one where filling it from a search would be easiest and worst. The same model name and the same generation code cover a truck sold on several continents with different engines, different gearboxes and different axles, so a ratio found for a Ranger is not necessarily a ratio for the North American one.

Where you can find it, the gear ratio calculator will take it along with the two sizes and return both the restoring ratio and the nearest ratio actually sold.

Same nameplate, different trucks

The T6 architecture underpins a Ranger sold in many markets, and the fitments recorded here are the North American ones for the 2019–2023 model years. A specification sheet found for another market's version of the same truck is not describing the same tire sizes, and neither is one for the generation that followed.

Your own door placard resolves that instantly, and it is the reason it exists.

What this does not settle

Whether any of these clears the Ranger's front end at full lock, with or without the suspension changes owners commonly make first. Contact happens at the widest point of the casing — which sits roughly at mid-sidewall height, not at the tread — against the liner and the control arm, and that point moves inboard and outboard with wheel offset, a number this page never sees.