2018 BMW 440i — Convertible Base Model
The 2018 BMW 440i Convertible Base Model shipped with 3 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.
225/50R17
| Section width | 225 mm |
|---|---|
| Aspect ratio (sidewall height) | 50% (112.5 mm) |
| Rim diameter | 17" |
| Overall tire diameter | ~25.9" |
| Revolutions per mile | ~780 |
Compare prices at:
225/45R18
| Section width | 225 mm |
|---|---|
| Aspect ratio (sidewall height) | 45% (101.3 mm) |
| Rim diameter | 18" |
| Overall tire diameter | ~26" |
| Revolutions per mile | ~777 |
Compare prices at:
225/40R19
| Section width | 225 mm |
|---|---|
| Aspect ratio (sidewall height) | 40% (90 mm) |
| Rim diameter | 19" |
| Overall tire diameter | ~26.1" |
| Revolutions per mile | ~773 |
Compare prices at:
What this size means for your BMW 440i
On the 2018 BMW 440i Convertible Base Model, the factory 225/50R17 measures about 25.9″ in overall diameter with a 112.5 mm (4.4″) sidewall, and completes roughly 780 revolutions per mile. Its 50-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.
The 225/50R17 and 225/45R18 roll within 0.1″ (0.4%) of each other in overall diameter, so they are interchangeable from a speedometer standpoint — the second size is an optional wheel package rather than a different rolling size.
Other 2018 BMW 440i trims
- Convertible Base Model Staggered Tires 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- Convertible M Sport 225/45R18 / 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- Convertible with M Sport Brakes 225/40R19 (Front) / 255/35R19 (Rear)
- Coupe Base Model 225/50R17 / 225/45R18 / 225/40R19
- Coupe Base Model Staggered Tires 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- Coupe M Sport 225/45R18 / 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- Coupe Track Handling Package 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- Gran Coupe Base Model 225/50R17 / 225/45R18 / 225/40R19
- Gran Coupe Base Model Staggered Tires 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- Gran Coupe M Sport 225/45R18 / 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- Gran Coupe Track Handling Package 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- xDrive Convertible Base Model 225/50R17 / 225/45R18 / 225/40R19
- xDrive Convertible Base Model Staggered Tires 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- xDrive Convertible M Sport 225/45R18 / 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- xDrive Convertible M Sport Brakes 225/40R19 (Front) / 255/35R19 (Rear)
- xDrive Coupe Base Model 225/45R18 / 225/40R19
- xDrive Coupe Base Model Staggered Tires 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- xDrive Coupe M Sport 225/45R18 / 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- xDrive Coupe Track Handling Package 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- xDrive Gran Coupe Base Model 225/50R17 / 225/45R18 / 225/40R19
- xDrive Gran Coupe Base Model Staggered Tires 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- xDrive Gran Coupe M Sport 225/45R18 / 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
- xDrive Gran Coupe Track Handling Package 225/45R18 (Front) / 255/40R18 (Rear) / 225/40R19 (Front) / 255/35R19 (Rear)
BMW 440i tire sizes by year
- 2020 BMW 440i 225/45R18 / 225/40R19 / 225/40R19 (Front) / 255/35R19 (Rear)
- 2019 BMW 440i 225/45R18 / 225/40R19 / 225/40R19 (Front) / 255/35R19 (Rear)
- 2017 BMW 440i 225/50R17 / 225/45R18 / 225/40R19
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.