The BMW 1 Series M135i xDrive Steptronic, produced from 2019 to 2020, represents the performance pinnacle of the F40 generation 1 Series hatchback. Positioned as the flagship model, it brought BMW’s M Performance tuning to the front-wheel-drive based (with xDrive all-wheel drive available) platform for the first time. This variant aimed to deliver a compelling blend of everyday practicality, engaging driving dynamics, and potent power, appealing to enthusiasts seeking a premium hot hatch experience. It served as a bridge between the standard 1 Series models and the more focused, track-oriented M cars.
Technical Specifications
| Brand | BMW |
| Model | 1 Series |
| Generation | 1 Series Hatchback (F40) |
| Type | M135i (306 Hp) xDrive Steptronic |
| Start of production | 2019 |
| End of production | 2020 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Hatchback |
| Seats | 5 |
| Doors | 5 |
| Fuel consumption (urban) | 8.2 l/100 km (28.7 US mpg, 34.4 UK mpg, 12.2 km/l) |
| Fuel consumption (extra urban) | 6 l/100 km (39.2 US mpg, 47.1 UK mpg, 16.7 km/l) |
| Fuel consumption (combined) | 6.8-7.1 l/100 km (34.6 – 33.1 US mpg, 41.5 – 39.8 UK mpg, 14.7 – 14.1 km/l) |
| CO2 emissions | 155-162 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 4.8 sec |
| Acceleration 0 – 62 mph | 4.8 sec |
| Acceleration 0 – 60 mph | 4.6 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 6d – TEMP |
| Weight-to-power ratio | 5 kg/Hp, 200.7 Hp/tonne |
| Weight-to-torque ratio | 3.4 kg/Nm, 295.1 Nm/tonne |
| Power | 306 Hp @ 4500-6250 rpm |
| Power per litre | 153.2 Hp/l |
| Torque | 450 Nm @ 1750-5000 rpm (331.9 lb.-ft. @ 1750-5000 rpm) |
| Engine layout | Front, Transverse |
| Engine Model/Code | B48A20E |
| 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 | 9.5:1 |
| 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) |
| Kerb Weight | 1525 kg (3362.05 lbs.) |
| Max. weight | 2085 kg (4596.64 lbs.) |
| Max load | 560 kg (1234.59 lbs.) |
| Trunk (boot) space – minimum | 380 l (13.42 cu. ft.) |
| Trunk (boot) space – maximum | 1200 l (42.38 cu. ft.) |
| Fuel tank capacity | 50 l (13.21 US gal | 11 UK gal) |
| Max. roof load | 75 kg (165.35 lbs.) |
| Permitted towbar download | 75 kg (165.35 lbs.) |
| Length | 4319 mm (170.04 in.) |
| Width | 1799 mm (70.83 in.) |
| Width including mirrors | 2081 mm (81.93 in.) |
| Height | 1434 mm (56.46 in.) |
| Wheelbase | 2670 mm (105.12 in.) |
| Front track | 1560 mm (61.42 in.) |
| Rear (Back) track | 1563 mm (61.54 in.) |
| Front overhang | 857 mm (33.74 in.) |
| Rear overhang | 792 mm (31.18 in.) |
| Ride height (ground clearance) | 153 mm (6.02 in.) |
| Drag coefficient (Cd) | 0.34 |
| Minimum turning circle | 11.4 m (37.4 ft.) |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 8 gears, automatic transmission Steptronic |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
| Tires size | 225/40 R18 92 Y XL |
| Wheel rims size | 8J x 18 |
Powertrain & Engine Architecture
At the heart of the M135i xDrive Steptronic lies the BMW B48A20E 2.0-liter inline-four cylinder engine. This engine is a member of BMW’s modular engine family, utilizing a single-scroll, twin-turbocharger configuration. Direct fuel injection, operating at a maximum pressure of 350 bar, ensures precise fuel delivery for optimal combustion. The engine boasts a compression ratio of 9.5:1. The B48 engine is known for its robust construction and ability to handle increased boost pressures, a key factor in achieving the M135i’s 306 horsepower output at 4500-6250 rpm and 450 Nm (331.9 lb-ft) of torque between 1750-5000 rpm. The engine also features an integrated exhaust manifold for improved turbocharger response. Paired with the engine is the 8-speed Steptronic automatic transmission, known for its smooth and quick shifts. This transmission features a torque converter and allows for both automatic and manual gear selection via steering wheel-mounted paddles. The xDrive all-wheel-drive system intelligently distributes power between the front and rear axles, enhancing traction and stability, particularly in adverse weather conditions.
Driving Characteristics
The M135i xDrive Steptronic delivers a noticeably brisk driving experience. The 4.8-second 0-60 mph acceleration time is indicative of its performance capabilities. The eight-speed automatic transmission is well-tuned, providing seamless gear changes and contributing to a refined driving experience. While not as raw or visceral as some dedicated performance cars, the M135i offers a good balance between comfort and sportiness. The xDrive system provides excellent grip, allowing for confident cornering and acceleration out of bends. Compared to the standard 1 Series variants, the M135i offers significantly more power and torque, resulting in a more engaging and responsive driving experience. The gear ratios are optimized for both acceleration and fuel efficiency, with a relatively short final drive to maximize responsiveness.
Equipment & Trim Levels
The M135i xDrive Steptronic came generously equipped as standard. Interior features included sport seats upholstered in a combination of cloth and Alcantara, a leather-wrapped M Sport steering wheel, and aluminum interior trim. Standard technology included BMW’s iDrive infotainment system with a central touchscreen display, navigation, and Apple CarPlay compatibility. Optional extras included a panoramic sunroof, upgraded Harman Kardon sound system, adaptive cruise control, and a head-up display. Exterior features included M Sport styling cues, such as aggressive front and rear bumpers, side skirts, and a rear spoiler. Available paint colors included metallic and non-metallic options, and buyers could choose from a range of alloy wheel designs.
Chassis & Braking
The F40 1 Series chassis was significantly improved over its predecessor, featuring a more rigid body structure and a refined suspension setup. The M135i benefited from M Sport suspension, which lowered the ride height and provided firmer damping for improved handling. The front suspension utilized MacPherson struts, while the rear featured a multi-link setup. Braking duties were handled by ventilated disc brakes on all four wheels, providing ample stopping power. The M135i also featured BMW’s Dynamic Stability Control (DSC) system, which helped to maintain stability during cornering and emergency maneuvers.
Market Reception & Comparison
The M135i xDrive Steptronic was generally well-received by automotive critics. It was praised for its strong performance, refined driving dynamics, and practical hatchback body style. Some critics noted that the front-wheel-drive based platform, even with xDrive, didn’t quite deliver the same level of driving engagement as rear-wheel-drive BMWs. Compared to other hot hatches in its class, such as the Volkswagen Golf R and the Mercedes-AMG A35, the M135i offered a competitive blend of performance, features, and price. Fuel economy was respectable for a performance car, with combined figures ranging from 33.1 to 34.6 US mpg. Reliability reports have been generally positive, with the B48 engine proving to be a durable and dependable unit.
Legacy
The F40 1 Series M135i xDrive Steptronic represents a significant step forward for BMW’s compact car lineup. It successfully brought M Performance tuning to the 1 Series, offering a compelling alternative to traditional hot hatches. The B48 engine has proven to be a reliable and tunable powerplant, and the 8-speed Steptronic transmission continues to be a popular choice in BMW models. On the used car market, the M135i holds its value well, appealing to enthusiasts seeking a practical and engaging performance car. Its combination of power, technology, and everyday usability ensures its continued desirability for years to come.
