265/50R20 tire size in inches
A 265/50R20 tire is 30.43 inches tall and 10.43 inches wide on a 20-inch rim. These are nominal dimensions from the official sizing formula.
| Dimension | 265/50R20 | This size vs yours | |
|---|---|---|---|
| Overall diameter UN R30 §6.1.2.1 | 30.43 in 773.0 mm | ||
| Section width UN R30 §6.1.2.1 | 10.43 in 265.0 mm | ||
| Sidewall height UN R30 §6.1.2.1 | 5.22 in 132.5 mm | ||
| Rim diameter Marked on the tire | 20 in | ||
| Circumference From diameter | 95.61 in | ||
| Revolutions per mile From diameter | 663 | ||
| Allowed real diameter UN R30 §6.1.5 | 30.12–30.85 in |
Is 265/50R20 a 30-inch tire?
Yes. At 30.43 inches tall, 265/50R20 is commonly called a 30-inch tire. Inch-class names round to the nearest inch; the true nominal height is 30.43 in, and a new tire may legally measure between 30.12 and 30.85 in.
Speedometer change
Example: if your speedometer is calibrated for 265/65R17 and you fit 265/50R20, the tire is −0.4% in diameter, so your true speed differs from the reading as shown below. Enter your current size above to see your own figures.
| Reading | True speed | Difference |
|---|---|---|
| 30 mph | 29.9 mph | −0.1 mph |
| 45 mph | 44.8 mph | −0.2 mph |
| 55 mph | 54.8 mph | −0.2 mph |
| 60 mph | 59.7 mph | −0.3 mph |
| 70 mph | 69.7 mph | −0.3 mph |
| 80 mph | 79.7 mph | −0.3 mph |
Sizes within 3% of 265/50R20
These sizes are within 3% of the diameter of 265/50R20. The 3% figure is a rule of thumb, not a regulation and not a fitment check: wheel width, offset, suspension and body clearance decide what fits. See changing tire size.
| Size | Diameter (in) | Width (in) | Change | ±3% | Ride height (in) |
|---|---|---|---|---|---|
| 245/65R17 | 29.54 | 9.65 | −2.9% | −0.45 | |
| 255/70R16 | 30.06 | 10.04 | −1.2% | −0.19 | |
| 265/50R20 | 30.43 | 10.43 | — | — | |
| 245/75R16 | 30.47 | 9.65 | +0.1% | +0.02 | |
| 245/70R17 | 30.50 | 9.65 | +0.2% | +0.04 | |
| 265/60R18 | 30.52 | 10.43 | +0.3% | +0.04 | |
| 265/65R17 | 30.56 | 10.43 | +0.4% | +0.06 | |
| 265/70R16 | 30.61 | 10.43 | +0.6% | +0.09 | |
| 265/75R15 | 30.65 | 10.43 | +0.7% | +0.11 | |
| 255/70R17 | 31.06 | 10.04 | +2.0% | +0.31 |
Inch equivalent of 265/50R20
In inch terms, 265/50R20 is about 30.4x10.4R20: 30.4 in tall and 10.4 in wide, a 30-inch tire.
| Inch size | Diameter (in) | Change | Width (in) | Dimensions from |
|---|---|---|---|---|
| 31x10.50R15 | 30.51 | +0.3% | 10.55 | UN R54 table |
| 31x11.50R15 | 30.51 | +0.3% | 11.42 | UN R54 table |
How 265/50R20 is calculated
265 mm section width × 50% aspect ratio = 132.5 mm sidewall (5.22 in).
Overall diameter = rim + 2 × sidewall = 20 in + 2 × 5.22 in = 30.43 in.
Formula: UN Regulation No. 30 §2.15 and §6.1.2.1 (passenger) and UN Regulation No. 54 §6.1.2.1 (light truck). Revolutions per mile = 63,360 ÷ circumference. Full sources are listed at the end of this page.
Questions about 265/50R20
- How tall is a 265/50R20 tire?
- 30.43 inches (773.0 mm) nominal. A new tire may measure from 30.12 to 30.85 in under the official tolerance; the maker's specification gives the figure for a specific tire.
- How wide is a 265/50R20 tire?
- 10.43 inches (265.0 mm) section width. Overall width can be slightly larger; for passenger tires, US rule FMVSS 139 allows 7% over the specified width (or 10 mm, if larger, for some pressure classes).
- How many revolutions per mile does 265/50R20 make?
- About 663 nominal, from a circumference of 95.61 in. Tire makers publish measured revolutions per mile for each tire.
- Will 265/50R20 fit my vehicle?
- This page can't tell you. Check the tire size on your door-jamb placard, then confirm wheel width, offset and clearance with the tire or vehicle maker.
Related
- All 20" sizes
- All 265 mm sizes
- Tire size chart
- Wheel offset calculator
- Re-gear calculator
- Plus-size calculator
Printed from https://tiresizecalc.net/size/265-50r20/. Figures as published on 2026-11-01. The full working and the official sources are on that page.
Sources
This size is listed by the manufacturer: Goodyear Assurance WeatherReady 2, checked on the manufacturer's site on 2026-11-01. The size page shows nominal figures, not that product's measurements.
- UN Regulation No. 30 - Uniform provisions concerning the approval of pneumatic tyres for motor vehicles and their trailers (Revision 3). United Nations Economic Commission for Europe (UNECE). E/ECE/324 E/ECE/TRANS/505 Rev.1/Add.29/Rev.3. 2007-03-29. Para 2.15 and 6.1.2.1: aspect ratio and outer diameter, D = d + 2H. Retrieved 2026-11-01.
- UN Regulation No. 54 - Uniform provisions concerning the approval of pneumatic tyres for commercial vehicles and their trailers (Revision 2). United Nations Economic Commission for Europe (UNECE). E/ECE/324 E/ECE/TRANS/505 Rev.1/Add.53/Rev.2. 2004-04-16. Para 6.1.2.1: the same formula for light truck tires. Retrieved 2026-11-01.
- UN Regulation No. 30 - Uniform provisions concerning the approval of pneumatic tyres for motor vehicles and their trailers (Revision 3). United Nations Economic Commission for Europe (UNECE). E/ECE/324 E/ECE/TRANS/505 Rev.1/Add.29/Rev.3. 2007-03-29. Para 6.1.5: allowed outer diameter, Dmin = d + 2H x 0.97, Dmax = d + 2H x 1.04. Retrieved 2026-11-01.
- Computed by tiresizecalc.net from the cited formula. Sri Murugan Systems. Circumference = pi x diameter; revolutions per mile = 63,360 / circumference; 1 in = 25.4 mm exactly. Retrieved 2026-11-01.
- 49 CFR 571.139 - Standard No. 139; New pneumatic radial tires for light vehicles. National Highway Traffic Safety Administration (NHTSA), Code of Federal Regulations (eCFR). 49 CFR 571.139. eCFR up to date as of 2026-10-15. S6.1.2: passenger tire width up to 7 percent (or 10 mm) over the specified width. Retrieved 2026-11-01.
- 49 CFR 571.110 - Standard No. 110; Tire selection and rims for motor vehicles with a GVWR of 4,536 kilograms (10,000 pounds) or less. National Highway Traffic Safety Administration (NHTSA), Code of Federal Regulations, annual edition (GovInfo). 2006-10-01. S4.3: the door placard shows the original tire size. Retrieved 2026-11-01.
Last reviewed 2026-11-01. The full source list, with dates and file checksums, is in How the numbers are calculated. To report an error, email contactus@tiresizecalc.net.