# 225/40 R18

## What size is 225/40 R18?

225/40 R18 has an overall diameter of about 25.09 in, a section width of 8.86 in and a sidewall height of 3.54 in. It turns roughly 804 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.

## Specification

| Specification | |
|---|---|
| Overall diameter | 25.09 in |
| Section width | 8.86 in |
| Sidewall height | 3.54 in |
| Circumference | 78.81 in |
| Revolutions | 500 /km · 804 /mi |

## In-tolerance sizes

| Size | Diameter | Speedo | Verdict |
|---|---|---|---|
| [255/35 R18](https://tirefitlab.com/255-35-r18.md) | -0.2% | -0.2% | ✓ OK |
| [195/65 R15](https://tirefitlab.com/195-65-r15.md) | -0.4% | -0.4% | ✓ OK |
| [225/35 R19](https://tirefitlab.com/225-35-r19.md) | +0.5% | +0.5% | ✓ OK |
| [225/45 R17](https://tirefitlab.com/225-45-r17.md) | -0.5% | -0.5% | ✓ OK |
| [195/60 R16](https://tirefitlab.com/195-60-r16.md) | +0.5% | +0.5% | ✓ OK |
| [205/55 R16](https://tirefitlab.com/205-55-r16.md) | -0.8% | -0.8% | ✓ OK |
| [215/55 R16](https://tirefitlab.com/215-55-r16.md) | +0.9% | +0.9% | ✓ OK |
| [225/50 R16](https://tirefitlab.com/225-50-r16.md) | -0.9% | -0.9% | ✓ OK |
| [235/45 R17](https://tirefitlab.com/235-45-r17.md) | +1.0% | +1.0% | ✓ OK |
| [235/40 R18](https://tirefitlab.com/235-40-r18.md) | +1.3% | +1.3% | ✓ OK |
| [195/70 R14](https://tirefitlab.com/195-70-r14.md) | -1.3% | -1.3% | ✓ OK |
| [215/50 R17](https://tirefitlab.com/215-50-r17.md) | +1.5% | +1.5% | ✓ OK |

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Methodology: https://tirefitlab.com/methodology/ · Tire size calculator: https://tirefitlab.com/225-40-r18/

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