2020 Audi A4 — Allroad Prestige

The 2020 Audi A4 Allroad Prestige came from the factory equipped with 245/45R18 tires. If your vehicle has since been fitted with aftermarket or upsized wheels, your actual tire size may no longer match this factory spec — always confirm against your door placard before buying.

245/45R18

Section width245 mm
Aspect ratio (sidewall height)45% (110.3 mm)
Rim diameter18"
Overall tire diameter~26.7"
Revolutions per mile~756

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What this size means for your Audi A4

On the 2020 Audi A4 Allroad Prestige, the factory 245/45R18 measures about 26.7″ in overall diameter with a 110.3 mm (4.3″) sidewall, and completes roughly 756 revolutions per mile. Its 45-series aspect ratio gives a low-profile sidewall tuned for sharper handling, common on sport trims and larger-wheel packages. In tire terms it is a passenger (P-metric / Euro-metric) size.

Other 2020 Audi A4 trims

Audi A4 tire sizes by year

See every Audi A4 year & trim →

How to read a tire size

A tire size like 225/45R17 breaks down into three parts: the first number is the section width in millimeters (the tire's width from sidewall to sidewall), the second is the aspect ratio — the sidewall's height as a percentage of that width — and the number after the "R" is the rim diameter in inches. A letter prefix (P or LT) indicates Passenger or Light Truck construction; its absence usually means Euro-metric sizing.

Some trucks and off-road tires instead use "flotation" sizing, like 37X12.50R17 — here the numbers are the tire's overall diameter and width in inches directly, with the rim diameter last.

Always verify against the tire information placard on your driver's-side door jamb or your owner's manual before purchasing — tire size can vary by factory option package even within the same trim.