37-Inch Tires: Metric and Flotation Sizes That Measure 37″

Table 1

16 sizes that measure 36.5–37.5″

3 metric and 13 flotation sizes, by rim. Diameter by the formula; measured range from the makers’ size tables.

37-inch tire sizes
Size	Rim	Diameter	Width	Measured	Models
37x14.50R15 flotation	15″	37.00″	14.5″	36.70″	1 · 1 brand
385/70R16	16″	37.22″	15.2″	37.72″	1 · 1 brand
315/80R17	17″	36.84″	12.4″	36.85″	1 · 1 brand
37x11.50R17 flotation	17″	37.00″	11.5″	36.54″	1 · 1 brand
37x12.50R17 flotation	17″	37.00″	12.5″	36.50–36.85″	9 · 3 brands
37x13.50R17 flotation	17″	37.00″	13.5″	36.50–37.05″	5 · 2 brands
37x11.50R18 flotation	18″	37.00″	11.5″	36.77″	1 · 1 brand
37x12.50R18 flotation	18″	37.00″	12.5″	36.50–36.77″	6 · 2 brands
37x13.50R18 flotation	18″	37.00″	13.5″	36.77–37.05″	3 · 2 brands
37x11.50R20 flotation	20″	37.00″	11.5″	36.54–36.77″	3 · 1 brand
37x12.50R20 flotation	20″	37.00″	12.5″	36.50–36.80″	10 · 3 brands
37x13.50R20 flotation	20″	37.00″	13.5″	36.50–37.05″	9 · 3 brands
37x12.50R22 flotation	22″	37.00″	12.5″	36.50–36.80″	5 · 2 brands
37x13.50R22 flotation	22″	37.00″	13.5″	36.50–37.05″	8 · 3 brands
37x13.50R24 flotation	24″	37.00″	13.5″	36.50–37.00″	5 · 2 brands
375/45R24	24″	37.29″	14.8″	37.56″	1 · 1 brand

Models: tire models and brands in the makers’ size tables we read. Sizes with a sheet of their own are links. A size in this list is not a fit promise: clearance depends on the vehicle, wheels and suspension.

§ 1

What does 37-inch mean?

“37-inch” describes a nominal diameter group, not a single width or wheel diameter. A flotation size such as 37x12.50R17 names its nominal diameter, width and rim diameter in inches.

Metric sizes express section width in millimeters and sidewall height as a percentage of that width. Diameter by the formula combines those sidewalls with the rim diameter, so few metric sizes equal exactly 37 in.

§ 2

Which metric sizes are near 37 inches?

The metric sizes below fall within 0.5 in of 37 in by the formula. These are nominal, unloaded diameters rather than measurements of a particular tire model.

Use the linked size pages in the table to examine each size separately. The tire size converter also explains the relationship between metric labels and inch dimensions.

16 in rim: 385/70R16 — 37.2 in nominal diameter.
17 in rim: 315/80R17 — 36.8 in nominal diameter.
24 in rim: 375/45R24 — 37.3 in nominal diameter.

§ 3

Do maker-listed diameters equal the label?

The measured table draws from official size tables published by Nitto, Toyo, Kumho, Mickey Thompson and Firestone, checked on October 15, 2026. Across those tables, published diameters for 37x12.50R17 range from 36.5 in to 36.85 in, versus 37.00 in nominal.

For 37x12.50R20, the maker tables list diameters from 36.5 in to 36.8 in. Compare the specific model’s published dimensions rather than treating all tires with the same label as identical.

37x11.50R17: 37.0 in nominal diameter and 11.50 in nominal width.
37x12.50R17: 37.0 in nominal diameter and 12.50 in nominal width.
37x13.50R17: 37.0 in nominal diameter and 13.50 in nominal width.
37x14.50R15: 37.0 in nominal diameter and 14.50 in nominal width.

§ 4

What changes from 265/70R17?

Using 385/70R16 as the example, nominal diameter rises from 31.6 in (803 mm) to 37.2 in (945 mm). By the formula, that is a 17.8% increase, with axle ground clearance increasing by 2.81 in (71 mm).

Without speedometer correction, 60 mph indicated becomes 70.7 mph true; 100 km/h indicated becomes 117.8 km/h true by the formula. Use the speedometer calculator to compare indicated and true speed.

At 65 mph with a 3.73 axle ratio and a 1.00 transmission gear, calculated engine speed falls from 2,578 rpm to 2,190 rpm. The gear ratio calculator gives a theoretical restoring ratio of 4.39, not a recommendation for a particular vehicle.

The 17.8% diameter increase is outside the ±3% comparison window. That window is a tire-shop rule of thumb, not a law or a vehicle maker specification.

Q&A

Common questions

What size is a 37-inch tire in metric?

There is no single metric equivalent. By the formula, 315/80R17 measures 36.8 in, 385/70R16 measures 37.2 in and 375/45R24 measures 37.3 in.

Are 37-inch tires actually 37 inches tall?

Not necessarily. Across the maker tables from Nitto, Toyo, Kumho, Mickey Thompson and Firestone, 37x13.50R17 has published diameters from 36.5 in to 37.05 in.

How wide is a 37-inch tire?

Diameter does not determine width. Examples include 37x11.50R17, 37x12.50R17 and 37x13.50R17, with nominal widths of 11.50 in, 12.50 in and 13.50 in.

Will 37-inch tires lower engine rpm?

In the calculated change from 265/70R17 to 385/70R16, engine speed drops 15.1% at the same road speed, axle ratio and transmission gear. That calculation does not describe every tire sold as a 37-inch size.

33″22 metric and 11 flotation sizes measure 32.5–33.5″ by the formula305/70R16 · 285/75R16 · 295/75R16 · 305/65R17 · 285/70R17 35″15 metric and 16 flotation sizes measure 34.5–35.5″ by the formula315/75R16 · 325/65R18 · 305/70R18 · 285/75R18 · 285/65R20 37″3 metric and 13 flotation sizes measure 36.5–37.5″ by the formula385/70R16 · 315/80R17 · 375/45R24