1999 BMW 540i — Wagon

The 1999 BMW 540i Wagon came from the factory equipped with 225/55R16 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.

225/55R16

Section width225 mm
Aspect ratio (sidewall height)55% (123.8 mm)
Rim diameter16"
Overall tire diameter~25.7"
Revolutions per mile~783

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What this size means for your BMW 540i

On the 1999 BMW 540i Wagon, the factory 225/55R16 measures about 25.7″ in overall diameter with a 123.8 mm (4.9″) sidewall, and completes roughly 783 revolutions per mile. Its 55-series aspect ratio gives a balanced everyday-passenger profile — enough sidewall to soak up road shock while keeping steering response crisp. In tire terms it is a passenger (P-metric / Euro-metric) size.

On a vehicle of this age, the BMW 540i may have been refitted with a slightly different replacement size somewhere in its life, so check the current sidewall — not just the factory spec — before buying.

Other 1999 BMW 540i trims

BMW 540i tire sizes by year

See every BMW 540i 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.