1999 BMW 540i — Base Model
The 1999 BMW 540i Base Model shipped with 2 different factory tire sizes, depending on the wheel package it left the factory with (this can also reflect a staggered front/rear setup). Check your tire sidewall or door placard to confirm which one applies to your vehicle.
This trim shipped with more than one tire size (staggered fitment, front/rear, or optional wheel package). Confirm which one matches your vehicle by checking your tire sidewall or door placard.
235/45R17 (Front)
| Section width | 235 mm |
|---|---|
| Aspect ratio (sidewall height) | 45% (105.8 mm) |
| Rim diameter | 17" |
| Overall tire diameter | ~25.3" |
| Revolutions per mile | ~796 |
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255/40R17 (Rear)
| Section width | 255 mm |
|---|---|
| Aspect ratio (sidewall height) | 40% (102 mm) |
| Rim diameter | 17" |
| Overall tire diameter | ~25" |
| Revolutions per mile | ~806 |
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What this size means for your BMW 540i
On the 1999 BMW 540i Base Model, the factory 235/45R17 measures about 25.3″ in overall diameter with a 105.8 mm (4.2″) sidewall, and completes roughly 796 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.
This is a staggered setup: the front axle runs 235/45R17 and the rear runs 255/40R17. The two sizes are not interchangeable, so order each for its correct axle and don't rotate front-to-rear.
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
- 6-Speed 235/45R17
- Wagon 225/55R16
- Wagon Sport Package 235/45R17
BMW 540i tire sizes by year
- 2026 BMW 540i 245/45R19 / 245/40R20 (Front) / 275/35R20 (Rear)
- 2025 BMW 540i 245/45R19 / 245/40R20 (Front) / 275/35R20 (Rear)
- 2024 BMW 540i 245/45R19 / 245/40R20 (Front) / 275/35R20 (Rear)
- 2022 BMW 540i 245/40R19 / 245/40R19 (Front) / 275/35R19 (Rear) / 245/35R20 (Front) / 275/30R20 (Rear)
- 2021 BMW 540i 245/45R18 / 245/40R19 / 245/40R19 (Front) / 275/35R19 (Rear)
- 2020 BMW 540i 245/45R18 / 245/40R19 / 245/40R19 (Front) / 275/35R19 (Rear)
- 2019 BMW 540i 245/45R18 / 245/40R19 / 245/40R19 (Front) / 275/35R19 (Rear)
- 2018 BMW 540i 245/45R18 / 245/40R19 / 245/40R19 (Front) / 275/35R19 (Rear)
- 2017 BMW 540i 245/45R18 / 245/40R19 / 245/40R19 (Front) / 275/35R19 (Rear)
- 2003 BMW 540i 235/40R18 (Front) / 265/35R18 (Rear)
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.