/40 series tire aspect ratio
What does /40 mean in a tire size?
A /40 aspect ratio means the tire sidewall height is 40% of the section width. For a 205/40R16 tire, the sidewall is 82mm tall. Common 40-series sizes span multiple rim diameters.
Popular sizes
- 225/40 R18
- 235/40 R18
- 245/40 R18
- 245/40 R19
- 255/40 R19
- 275/40 R19
- 275/40 R20
- 295/40 R20
- 305/40 R20
- 265/40 R22
- 285/40 R22
- 305/40 R22
Full aspect ratio guide · Tire section width guide · Tire size calculator
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.
- Technical check
- 2026-06-28
- Content updated
- 2026-06-21
What changed
- Checked generated routes, metadata, sitemap inclusion and localized page rendering.