The BMW 1 Series Sedan (F52) 125i, produced from October 2019 through 2024, marked BMW’s entry into the compact sedan market, primarily aimed at regions where sedan body styles are preferred – most notably China, Mexico, and other emerging markets. This variant, powered by a 2.0-liter turbocharged four-cylinder engine coupled with a 7-speed dual-clutch transmission (DCT), occupies a mid-range position within the F52 1 Series lineup. It offers a balance between performance and efficiency, sitting below the more powerful 135i models and above the base 118i, appealing to buyers desiring a sporty yet practical daily driver.
Technical Specifications
| Brand | BMW |
| Model | 1 Series |
| Generation | 1 Series Sedan (F52) |
| Type (Engine) | 125i (192 Hp) DCT |
| Start of production | October, 2019 |
| End of production | 2024 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (combined) | 5.8 l/100 km (40.6 US mpg, 48.7 UK mpg, 17.2 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 7.5 sec |
| Acceleration 0 – 62 mph | 7.5 sec |
| Acceleration 0 – 60 mph | 7.1 sec |
| Maximum speed | 235 km/h (146.02 mph) |
| Power | 192 Hp @ 5000-6000 rpm |
| Torque | 280 Nm @ 1350-4600 rpm (206.52 lb.-ft. @ 1350-4600 rpm) |
| Engine layout | Front, Transverse |
| Engine Model/Code | B48A20M0 |
| Engine displacement | 1998 cm3 (121.93 cu. in.) |
| Number of cylinders | 4 |
| Engine configuration | Inline |
| Cylinder Bore | 82 mm (3.23 in.) |
| Piston Stroke | 94.6 mm (3.72 in.) |
| Compression ratio | 11:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Twin-power turbo, Intercooler |
| Engine oil capacity | 5.25 l (5.55 US qt | 4.62 UK qt) |
| Fuel tank capacity | 50 l (13.21 US gal | 11 UK gal) |
| Length | 4462 mm (175.67 in.) |
| Width | 1803 mm (70.98 in.) |
| Height | 1448 mm (57.01 in.) |
| Wheelbase | 2670 mm (105.12 in.) |
| Drivetrain Architecture | Front wheel drive |
| Number of gears and type of gearbox | 7 gears, automatic transmission DCT |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
Powertrain & Engine Architecture
The 125i’s core is BMW’s B48A20M0 2.0-liter inline-four cylinder engine. This engine belongs to BMW’s modular engine family, renowned for its efficiency and performance. It employs direct fuel injection, delivering fuel directly into the combustion chamber for enhanced combustion efficiency and reduced emissions. The engine is turbocharged, utilizing a twin-scroll turbocharger to minimize turbo lag and provide a broad torque curve. An intercooler further boosts performance by cooling the intake air. The B48 engine incorporates variable valve timing (VANOS) and variable valve lift (Valvetronic) technologies, optimizing engine performance throughout the rev range.
The engine is paired with a 7-speed dual-clutch transmission (DCT). This transmission delivers rapid, seamless gear changes, contributing to both performance and fuel efficiency. The DCT operates with two separate clutches – one for odd-numbered gears and one for even-numbered gears – allowing for pre-selection of the next gear. This minimizes interruption in power delivery during shifts. The transmission features both automatic and manual shift modes, allowing the driver to select their preferred driving style.
Driving Characteristics
The 125i DCT provides a responsive and engaging driving experience. With 192 horsepower and 280 Nm (206 lb-ft) of torque, it offers brisk acceleration, reaching 0-60 mph in approximately 7.1 seconds. While not as overtly sporty as the higher-output 135i models, the 125i delivers ample power for everyday driving and confident highway merging. The DCT transmission contributes to smooth and quick gear changes, enhancing the overall driving experience. The front-wheel-drive configuration provides good traction in most conditions, although some torque steer may be noticeable under hard acceleration. The gear ratios are tuned for a balance between acceleration and fuel economy, with taller gears for efficient cruising.
Equipment & Trim Levels
The 125i typically came equipped with a respectable array of standard features. Interior appointments generally included cloth upholstery, though leather options were available. Standard features often included automatic climate control, a BMW iDrive infotainment system with a central display screen, and power windows and locks. Safety features such as ABS, stability control, and multiple airbags were standard. Optional extras included a sunroof, upgraded audio system, navigation system, parking sensors, and various driver-assistance features. Trim levels varied by market, but generally offered packages that bundled popular options together.
Chassis & Braking
The F52 1 Series Sedan utilizes a MacPherson strut front suspension and a multi-link rear suspension. This suspension setup provides a good balance between ride comfort and handling precision. The chassis is relatively lightweight, contributing to the car’s agility. The 125i is equipped with ventilated front disc brakes and solid rear disc brakes. ABS (Anti-lock Braking System) is standard, providing enhanced braking performance and stability. Electric power steering provides precise and responsive steering feel.
Market Reception & Comparison
The 125i DCT was generally well-received by automotive critics as a competent and enjoyable compact sedan. Reviewers praised its responsive engine, smooth-shifting transmission, and comfortable ride. Compared to the 118i, the 125i offered a significant performance upgrade. Compared to the 135i, it provided a more affordable entry point into the 1 Series range, albeit with less power. Fuel economy was considered competitive for its class, averaging around 40.6 US mpg in combined driving. Reliability reports have been generally positive, with the B48 engine proving to be a robust and dependable unit.
Legacy
The BMW 1 Series Sedan (F52) 125i DCT represents a significant offering in the compact sedan segment. The B48 engine and 7-speed DCT transmission have proven to be reliable and efficient powertrains. On the used car market, the 125i DCT holds its value reasonably well, appealing to buyers seeking a well-equipped, sporty, and reliable compact sedan. Its combination of performance, efficiency, and BMW’s reputation for build quality ensures its continued desirability for years to come. Regular maintenance, including oil changes and adherence to BMW’s recommended service intervals, is crucial for maintaining the long-term reliability of this powertrain.
