Metric to Inch Tire Size Converter

Flotation names are nominal: the unloaded design diameter rounds to friendly numbers, and the tire then sags under load (loaded radius runs 2–4% less), wears up to half an inch of tread away, and varies by manufacturer mold. A 285/75R16 computes to 32.8″ and typically stands 32.3–32.5″ mounted and loaded. Diameter math is for comparing sizes — measure the actual tire when clearance is tight.

Common equivalences: 33″ ≈ 285/75R16, 285/70R17 or 275/70R18; 35″ ≈ 315/75R16, 315/70R17 or 295/70R18; 37″ ≈ 355/70R17 or 37×12.50R17 sold directly in flotation. Note how the same nominal height spreads across rim sizes by trading sidewall — pick by the wheel you run, then verify the computed diameter here, because '35s' span 34.5 to 35.2 real inches across brands.

Flotation-size tires are usually built as LT (light truck) with tougher casings, higher load ranges, deeper tread and more weight; the metric 'equivalent' may be a P-metric or Euro-metric passenger construction. Same diameter, different animal: LT versions need higher pressures for the same load, ride stiffer, cost fuel economy, and shrug off rock damage their P-metric twins won't. The number on this page only settles geometry.

Yes — each tire has an approved rim-width range roughly centred on section width ÷ 25.4 minus 25%: a 285 (11.2″) tire wants about an 8–9.5″ rim. Too narrow a rim pinches the tread crown; too wide stretches the bead and exposes the rim lip. The flotation second number (the 11.50 in 33×11.50) is section width on the measuring rim, so it maps straight onto rim-width tables.