2020 BMW Alpina — B7 xDrive
The 2020 BMW Alpina B7 xDrive shipped with 4 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.
255/40R20 (Front)
| Section width | 255 mm |
|---|---|
| Aspect ratio (sidewall height) | 40% (102 mm) |
| Rim diameter | 20" |
| Overall tire diameter | ~28" |
| Revolutions per mile | ~719 |
Compare prices at:
295/35R20 (Rear)
| Section width | 295 mm |
|---|---|
| Aspect ratio (sidewall height) | 35% (103.3 mm) |
| Rim diameter | 20" |
| Overall tire diameter | ~28.1" |
| Revolutions per mile | ~717 |
Compare prices at:
245/35R21 (Front)
| Section width | 245 mm |
|---|---|
| Aspect ratio (sidewall height) | 35% (85.8 mm) |
| Rim diameter | 21" |
| Overall tire diameter | ~27.8" |
| Revolutions per mile | ~727 |
Compare prices at:
285/30R21 (Rear)
| Section width | 285 mm |
|---|---|
| Aspect ratio (sidewall height) | 30% (85.5 mm) |
| Rim diameter | 21" |
| Overall tire diameter | ~27.7" |
| Revolutions per mile | ~727 |
Compare prices at:
What this size means for your BMW Alpina
On the 2020 BMW Alpina B7 xDrive, the factory 255/40R20 measures about 28″ in overall diameter with a 102 mm (4″) sidewall, and completes roughly 719 revolutions per mile. Its 40-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 large-diameter fitment.
This is a staggered setup: the front axle runs 255/40R20 and the rear runs 295/35R20. The two sizes are not interchangeable, so order each for its correct axle and don't rotate front-to-rear.
BMW Alpina tire sizes by year
- 2025 BMW Alpina 245/40R20 (Front) / 275/35R20 (Rear) / 245/35R21 (Front) / 285/30R21 (Rear)
- 2024 BMW Alpina 245/40R20 (Front) / 275/35R20 (Rear) / 245/35R21 (Front) / 285/30R21 (Rear)
- 2023 BMW Alpina 245/40R20 (Front) / 275/35R20 (Rear) / 245/35R21 (Front) / 285/30R21 (Rear)
- 2022 BMW Alpina 255/40R20 (Front) / 295/35R20 (Rear) / 245/35R21 (Front) / 285/30R21 (Rear)
- 2021 BMW Alpina 255/40R20 (Front) / 295/35R20 (Rear) / 245/35R21 (Front) / 285/30R21 (Rear)
- 2019 BMW Alpina 255/35R20 (Front) / 295/30R20 (Rear) / 245/35R21 (Front) / 285/30R21 (Rear)
- 2018 BMW Alpina 255/35R20 (Front) / 295/30R20 (Rear) / 245/35R21 (Front) / 285/30R21 (Rear)
- 2017 BMW Alpina 255/35R20 (Front) / 295/30R20 (Rear) / 245/35R21 (Front) / 285/30R21 (Rear)
- 2016 BMW Alpina 255/35R20 (Front) / 295/30R20 (Rear) / 245/35R21 (Front) / 285/30R21 (Rear)
- 2013 BMW Alpina 245/35R21 (Front) / 285/30R21 (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.