The BMW 1 Series M135i xDrive Steptronic, produced from 2012 to 2015, represented a performance-focused variant within the F20 1 Series hatchback range. Positioned as the flagship model before the introduction of the M140i, the M135i aimed to deliver a compelling blend of everyday practicality and engaging driving dynamics. It was primarily marketed in Europe and other international markets, offering a more accessible entry point into the high-performance BMW lineup compared to larger M models. This specific configuration, pairing the potent N55 engine with the xDrive all-wheel-drive system and Steptronic automatic transmission, was a popular choice for buyers seeking all-weather capability and effortless performance.
Technical Specifications
| Brand | BMW |
| Model | 1 Series |
| Generation | 1 Series Hatchback 5dr (F20) |
| Type (Engine) | M135i (320 Hp) xDrive Steptronic |
| Start of production | 2012 |
| End of production | 2015 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Hatchback |
| Seats | 5 |
| Doors | 5 |
| Fuel consumption (economy) – urban | 10.8 l/100 km (21.8 US mpg, 26.2 UK mpg, 9.3 km/l) |
| Fuel consumption (economy) – extra urban | 6.1 l/100 km (38.6 US mpg, 46.3 UK mpg, 16.4 km/l) |
| Fuel consumption (economy) – combined | 7.8 l/100 km (30.2 US mpg, 36.2 UK mpg, 12.8 km/l) |
| CO2 emissions | 182 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 4.7 sec |
| Acceleration 0 – 62 mph | 4.7 sec |
| Acceleration 0 – 60 mph | 4.5 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 5 |
| Weight-to-power ratio | 4.8 kg/Hp, 210.5 Hp/tonne |
| Weight-to-torque ratio | 3.4 kg/Nm, 296.1 Nm/tonne |
| Power | 320 Hp @ 5800 rpm |
| Power per litre | 107.4 Hp/l |
| Torque | 450 Nm @ 1300-4500 rpm (331.9 lb.-ft. @ 1300-4500 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | N55B30A |
| Engine displacement | 2979 cm3 (181.79 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 84 mm (3.31 in.) |
| Piston Stroke | 89.6 mm (3.53 in.) |
| Compression ratio | 10.2:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Twin-power turbo, Intercooler |
| Engine oil capacity | 6.5 l (6.87 US qt | 5.72 UK qt) |
| Coolant | 6.7 l (7.08 US qt | 5.9 UK qt) |
| Kerb Weight | 1520 kg (3351.03 lbs.) |
| Max. weight | 2050 kg (4519.48 lbs.) |
| Max load | 530 kg (1168.45 lbs.) |
| Trunk (boot) space – minimum | 360 l (12.71 cu. ft.) |
| Trunk (boot) space – maximum | 1200 l (42.38 cu. ft.) |
| Fuel tank capacity | 52 l (13.74 US gal | 11.44 UK gal) |
| Max. roof load | 75 kg (165.35 lbs.) |
| Length | 4340 mm (170.87 in.) |
| Width | 1765 mm (69.49 in.) |
| Height | 1411 mm (55.55 in.) |
| Wheelbase | 2690 mm (105.91 in.) |
| Front track | 1512 mm (59.53 in.) |
| Rear (Back) track | 1532 mm (60.31 in.) |
| Ride height (ground clearance) | 130 mm (5.12 in.) |
| Drag coefficient (Cd) | 0.34 |
| Minimum turning circle | 11.3 m (37.07 ft.) |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 8 gears, automatic transmission Steptronic |
| Front suspension | Double wishbone |
| 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 |
| Tires size | 225/40 R18 88Y; 245/35 R18 92Y |
| Wheel rims size | 7.5J x 18; 8J x 18 |
INTRODUCTION
The BMW M135i xDrive Steptronic, launched in 2012, was a key model in revitalizing the 1 Series lineup. Built on the F20 chassis, the M135i aimed to bridge the gap between the standard 1 Series models and the full-fledged M cars. It was designed to appeal to enthusiasts who desired a practical, everyday hatchback with significant performance capabilities. The xDrive all-wheel-drive system and Steptronic automatic transmission were crucial components, enhancing both traction and driving ease, particularly in inclement weather conditions. This variant quickly gained popularity for its responsive handling, powerful engine, and relatively accessible price point within the premium hatchback segment.
Powertrain & Engine Architecture
At the heart of the M135i lies the N55B30A, a 3.0-liter inline-six cylinder engine. This engine is a significant departure from the four-cylinder engines found in lower trims of the F20 1 Series. The N55 utilizes direct fuel injection, a twin-scroll turbocharger, and Double-VANOS variable valve timing to deliver a potent 320 horsepower and 450 Nm (331.9 lb-ft) of torque. The turbocharger is strategically positioned to minimize turbo lag and provide a broad torque curve, peaking from 1300 to 4500 rpm. The engine’s longitudinal layout, a hallmark of BMW’s rear-wheel-drive-based platforms, contributes to balanced weight distribution. The Steptronic 8-speed automatic transmission is a crucial element, offering smooth and rapid gear changes. It features steering wheel-mounted paddle shifters for manual control, allowing drivers to engage more directly with the powertrain. The transmission is programmed for both efficient cruising and aggressive downshifts during spirited driving.
Driving Characteristics
The M135i xDrive Steptronic delivers a compelling driving experience. The combination of the powerful N55 engine, all-wheel drive, and the quick-shifting Steptronic transmission results in a 0-60 mph time of around 4.5 seconds. While not as raw or focused as a dedicated M car, the M135i offers a substantial performance upgrade over other 1 Series variants. The xDrive system provides excellent traction, particularly when accelerating out of corners or on slippery surfaces. The automatic transmission, while offering convenience, can sometimes feel slightly less engaging than a manual gearbox. However, the paddle shifters mitigate this, allowing for precise gear selection. The steering is precise and well-weighted, providing good feedback to the driver. Overall, the M135i strikes a balance between performance and usability, making it a rewarding daily driver.
Equipment & Trim Levels
The M135i xDrive Steptronic came generously equipped as standard. Key features included sport seats, a sport steering wheel, automatic climate control, and BMW’s iDrive infotainment system. Exterior styling cues included an aggressive front bumper, side skirts, and a rear diffuser. Optional extras were plentiful, allowing buyers to personalize their vehicles. Popular options included a sunroof, upgraded leather upholstery, a premium sound system, and parking assist features. The interior trim was typically finished in aluminum or high-gloss black accents, adding to the sporty ambiance. While not as lavishly appointed as some luxury hatchbacks, the M135i’s interior prioritized functionality and a driver-focused layout.
Chassis & Braking
The M135i’s chassis was specifically tuned to handle the increased power output. It featured a stiffer suspension setup compared to standard 1 Series models, with upgraded dampers and springs. The front suspension utilized a double wishbone design, while the rear employed an independent multi-link setup. This configuration provided excellent handling and stability. Braking duties were handled by ventilated discs on all four wheels, providing ample stopping power. The ABS (Anti-lock Braking System) and stability control systems were standard, enhancing safety and control. The xDrive all-wheel-drive system intelligently distributed torque between the front and rear axles, optimizing traction in various driving conditions.
Market Reception & Comparison
The M135i xDrive Steptronic was generally well-received by automotive critics. It was praised for its powerful engine, engaging handling, and all-weather capability. Compared to its rivals, such as the Audi S3 and Mercedes-Benz A45 AMG, the M135i offered a unique blend of performance and practicality. While the Audi S3 provided a more refined interior, and the A45 AMG boasted even more raw power, the M135i struck a compelling balance. Fuel economy was respectable for a performance hatchback, averaging around 30.2 US mpg in combined driving. Reliability was generally good, although some owners reported minor issues with the turbocharger and cooling system.
Legacy
The BMW M135i xDrive Steptronic has established itself as a desirable used car. The N55 engine is known for its durability and tunability, making it a popular choice for enthusiasts. While maintenance costs can be higher than those of four-cylinder models, the M135i’s performance and driving experience justify the expense for many owners. The xDrive system continues to provide confidence in all weather conditions. Today, the M135i represents a sweet spot in the BMW lineup, offering a compelling combination of performance, practicality, and value. It remains a popular choice for those seeking a high-performance hatchback that is both engaging to drive and capable of everyday use.
