# 255/55 R18

## What size is 255/55 R18?

255/55 R18 has an overall diameter of about 29.04 in, a section width of 10.04 in and a sidewall height of 5.52 in. It turns roughly 694 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.

## Specification

| Specification | |
|---|---|
| Overall diameter | 29.04 in |
| Section width | 10.04 in |
| Sidewall height | 5.52 in |
| Circumference | 91.24 in |
| Revolutions | 431 /km · 694 /mi |

## In-tolerance sizes

| Size | Diameter | Speedo | Verdict |
|---|---|---|---|
| [255/50 R19](https://tirefitlab.com/255-50-r19.md) | -0.0% | -0.0% | ✓ OK |
| [255/45 R20](https://tirefitlab.com/255-45-r20.md) | -0.0% | -0.0% | ✓ OK |
| [235/65 R17](https://tirefitlab.com/235-65-r17.md) | -0.1% | -0.1% | ✓ OK |
| [285/45 R19](https://tirefitlab.com/285-45-r19.md) | +0.2% | +0.2% | ✓ OK |
| [235/60 R18](https://tirefitlab.com/235-60-r18.md) | +0.2% | +0.2% | ✓ OK |
| [295/35 R21](https://tirefitlab.com/295-35-r21.md) | +0.3% | +0.3% | ✓ OK |
| [235/55 R19](https://tirefitlab.com/235-55-r19.md) | +0.5% | +0.5% | ✓ OK |
| [295/40 R20](https://tirefitlab.com/295-40-r20.md) | +0.9% | +0.9% | ✓ OK |
| [275/45 R19](https://tirefitlab.com/275-45-r19.md) | -1.0% | -1.0% | ✓ OK |
| [265/45 R20](https://tirefitlab.com/265-45-r20.md) | +1.2% | +1.2% | ✓ OK |
| [245/45 R20](https://tirefitlab.com/245-45-r20.md) | -1.2% | -1.2% | ✓ OK |
| [275/40 R20](https://tirefitlab.com/275-40-r20.md) | -1.3% | -1.3% | ✓ OK |

---

Methodology: https://tirefitlab.com/methodology/ · Tire size calculator: https://tirefitlab.com/255-55-r18/

> Geometry is computed in canonical millimetres and is deterministic across the site. Always verify physical clearance before fitting.