37x13.50 R20
What size is 37x13.50 R20?
37x13.50 R20 has an overall diameter of about 37.00 in, a section width of 13.50 in and a sidewall height of 8.50 in. It turns roughly 545 times per mile. Below are the exact figures plus plus/minus sizes that stay within the selected diameter tolerance.
- Overall diameter: 37.00 in.
- Section width: 13.50 in.
- Sidewall height: 8.50 in.
- Revolutions: 339 /km · 545 /mi.
Seasonal check
Planning a long summer drive?
Use the budget and running-cost tools before a trip, especially if the current tires are worn or the replacement size changes diameter.
What this geometry means
37x13.50 R20 has a taller-sidewall proportion. The marking directly specifies a 37.00 in nominal overall diameter, a 13.50 in section and a 20-inch rim. One sidewall is 8.50 in; both sidewalls make up 46% of the diameter, while the rim makes up 54%.
At the nominal 116.24 in circumference, 1,000 rotations cover 2.95 km (1.83 mi); the inverse rates are 339/km and 545/mi.
This is a nominal geometry comparison only. Vehicle clearance, wheel width and offset, load and speed ratings, and manufacturer approval still require separate checks.
Specification
| Overall diameter | 37.00 in |
|---|---|
| Section width | 13.50 in |
| Sidewall height | 8.50 in |
| Circumference | 116.24 in |
| Revolutions | 339 /km · 545 /mi |
Compare sizes
- Very close match · This rating covers tire geometry only, not vehicle compatibility.
- Diameter +0.0% · Ride-height change +0.00 in.
- Speedometer unchanged · 60 mph → 60.0 mph.
- Sidewall +0.00 in · Width +0.00 in.
How this result is calculated
Computed from nominal tire-size geometry: diameter, circumference and speedometer error. It does not check vehicle placard approval, load/speed rating, rim-width range, wheel-arch, suspension or brake clearance.
MethodologyBefore fitting
- Check the vehicle placard and owner’s manual first.
- Match or exceed the required load index and speed rating.
- Confirm rim-width range, bolt pattern, hub bore, offset and fasteners.
- Inspect wheel-arch, suspension and brake clearance under real vehicle load.
- Check TPMS, cold pressure and local roadworthiness rules.
- Diameter
- 37.00 in 37.00 in+0.00 in
- Sidewall
- 8.50 in 8.50 in+0.00 in
- Width
- 13.50 in 13.50 in+0.00 in
- Circumference
- 116.24 in 116.24 in+0.0%
- Revs / mile
- 545 545
- Speedo @ 60
- 60 mph 60.0 mph+0.0%
- Ride-height change
- 0.00 in +0.00 in
- True distance per 100 indicated
- 100 mi 100.0 mi+0.0%
- Current —
37x13.50 R20 - New —
37x13.50 R20 - Grounded to the road: the axle rises +0.00 in.
Result report
37x13.50 R20 37x13.50 R20 · Very close match · Within tolerance
Plan budget for this size: 37x13.50 R20
Copy/print uses this page state only; TireFitLab does not create an account or store a server-side report.
Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.
In-tolerance alternative sizes
| Size | Diameter | Speedo @ 100 | Use this |
|---|---|---|---|
−1″ 305/75R19 | +0.0% | +0.0% | |
OE 335/65R20 | +0.4% | +0.4% |
More tools
- How to read a tire size
- Plus sizing guide
- Speedometer error guide
- Section width guide
- Aspect ratio guide
- Rim diameter 20"
- Load index chart
- Speed rating chart
- Rim width and tire fitment guide
- Wheel offset guide
- Wheel spacers guide
- Tire pressure for heavy loads and towing
- Technical check
- 2026-07-22
- Content updated
- 2026-07-22
What changed
- Added a localized engine-derived geometry signature and matching Markdown narrative.