# 255/50R20 tire size in inches

- **Diameter:** 30.0 in
- **Width:** 10.0 in
- **Sidewall:** 5.02 in
- **Revs per mile:** 671

## Quick answer

A 255/50R20 tire is **30.0 inches** (763 mm) tall and **10.0 inches** (255 mm) wide, with a 5.02-inch sidewall, and fits a 20-inch wheel. In inch sizing that is roughly 30.0x10.0R20.

## 255/50R20 dimensions

| Measurement | Inches | Millimeters |
| --- | --- | --- |
| Overall diameter | 30.0 in | 763 mm |
| Section width | 10.0 in | 255 mm |
| Sidewall height | 5.02 in | 127.5 mm |
| Rim diameter | 20 in | 508 mm |
| Circumference | 94.4 in | 2397 mm |
| Revolutions per mile | 671 | -- |

## What does 255/50R20 mean?

| Part | Value | Meaning |
| --- | --- | --- |
| Width | 255 | The tire is 255 mm wide from sidewall to sidewall. |
| Aspect ratio | 50 | The sidewall is 50% as tall as the tire is wide (127.5 mm). |
| R | R | Radial construction (nearly every modern tire). |
| Rim | 20 | Fits a 20-inch wheel. |

The load index and speed rating that follow the size (for example "98H") are on the sidewall and in your door-jamb sticker. See the [load index chart](/tools/tire-load-index-chart) and [speed rating chart](/tools/tire-speed-rating-chart).

## What sizes can replace 255/50R20?

Sizes within 3% of the overall diameter, the usual limit for keeping the speedometer, ABS and stability control accurate. Check the width fits your wheel and fender, and match the load index.

| Size | Diameter | Difference | Speedometer at 60 mph |
| --- | --- | --- | --- |
| [255/55R19](/tools/tire-size/255-55r19) | 30.0 in | +0.0% | 60.0 mph actual |
| [265/50R20](/tools/tire-size/265-50r20) | 30.4 in | +1.3% | 60.8 mph actual |
| [245/75R16](/tools/tire-size/245-75r16) | 30.5 in | +1.4% | 60.9 mph actual |
| [245/70R17](/tools/tire-size/245-70r17) | 30.5 in | +1.5% | 60.9 mph actual |
| [245/60R18](/tools/tire-size/245-60r18) | 29.6 in | -1.5% | 59.1 mph actual |
| [265/60R18](/tools/tire-size/265-60r18) | 30.5 in | +1.6% | 61.0 mph actual |
| [245/65R17](/tools/tire-size/245-65r17) | 29.5 in | -1.7% | 59.0 mph actual |
| [265/65R17](/tools/tire-size/265-65r17) | 30.6 in | +1.7% | 61.0 mph actual |

## Frequently asked questions

### How tall is a 255/50R20 tire?

A 255/50R20 tire is 30.0 inches (763 mm) tall when new and correctly inflated. Real tires vary by a few tenths of an inch between brands and tread patterns.

### Can I put 255/50R20 tires on my car?

Only if your door-jamb placard or owner's manual lists 255/50R20, or a plus-size alternative within about 3% of the original diameter that clears the suspension. The wheel must be 20 inches in diameter and the right width for a 255 mm tire.

### How many revolutions per mile does a 255/50R20 tire make?

About 671 revolutions per mile, calculated from its 94.4-inch circumference. Manufacturers' published figures are usually slightly higher because a loaded tire squats a little.

## Other 20-inch sizes

- [265/50R20](https://diagxcar.com/tools/tire-size/265-50r20)
- [275/40R20](https://diagxcar.com/tools/tire-size/275-40r20)
- [275/55R20](https://diagxcar.com/tools/tire-size/275-55r20)
- [275/60R20](https://diagxcar.com/tools/tire-size/275-60r20)

## Tire tools

- [Tire size calculator](https://diagxcar.com/tools/tire-size-calculator)
- [Tire size decoder](https://diagxcar.com/tools/tire-size-decoder)
- [Load index chart](https://diagxcar.com/tools/tire-load-index-chart)
- [Speed rating chart](https://diagxcar.com/tools/tire-speed-rating-chart)

## Tire care

- [How long do tires last?](https://diagxcar.com/how-long/tires)
- [How often to rotate tires](https://diagxcar.com/how-often/rotate-tires)
- [Uneven tire wear](https://diagxcar.com/symptoms/uneven-tire-wear)

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Source page: https://diagxcar.com/tools/tire-size/255-50r20
General information, not a substitute for a qualified mechanic.