Segment:
        
        
            Compact Premium Convertible / Sporty Compact Sedan
        
     
    
        
            Target Audience:
        
        
            Enthusiast drivers seeking performance, luxury, and open-air driving in a compact package.
        
     
    
    
        
            Key Competitors:
        
        
            Audi A3 Cabriolet, Mercedes-Benz C-Class Cabriolet (though generally a class above), Infiniti G37 Convertible, Ford Mustang Convertible.
        
     
    
    
        
            Powertrain:
        
        
            Renowned N55 3.0L TwinPower Turbo inline-6 engine.
        
     
    
        
            Driving Dynamics:
        
        
            Rear-wheel drive platform, balanced chassis, and sport-tuned suspension for engaging handling.
        
     
    
        
            Convertible Experience:
        
        
            Power-operated soft top providing a true open-air driving experience.
        
     
    
        
            Premium Interior:
        
        
            BMW's signature driver-focused interior with high-quality materials and iDrive infotainment.
        
     
 
    
    
    
        
            Engine Operation:
        
        
            Detailed explanation of the N55 TwinPower Turbo inline-6 engine, including lubrication, cooling, and ignition systems.
        
     
    
        
            Drivetrain:
        
        
            Information on the rear-wheel-drive system, including differential operation and proper usage.
        
     
    
        
            Suspension And Steering:
        
        
            Overview of the suspension components and the Servotronic power steering system.
        
     
    
        
            Brakes:
        
        
            Explanation of the braking system, including ABS (Anti-lock Braking System) and DSC (Dynamic Stability Control).
        
     
    
        
            Electrical System:
        
        
            Details on the vehicle's electrical components, battery, lighting, and fuses.
        
     
    
        
            Convertible Top Operation:
        
        
            Comprehensive instructions for operating and maintaining the power-operated convertible soft top.
        
     
    
        
            Infotainment And Controls:
        
        
            Guidance on the iDrive infotainment system, climate control, audio system, and other interior features.
        
     
    
        
            Safety Systems:
        
        
            Explanation of airbags, seatbelts, ISOFIX child seat anchors, and driver assistance features.
        
     
    
        
            Instrument Cluster And Indicators:
        
        
            Detailed description of all gauges, warning lights, and indicator symbols.
        
     
    
        
            Lighting Systems:
        
        
            Information on headlights, taillights, interior lighting, and adaptive headlight functions.
        
     
    
        
            Comfort Features:
        
        
            Coverage of heated seats, power adjustments, and climate control settings.
        
     
    
    
        
            Starting And Driving:
        
        
            Basic instructions for starting the engine, shifting gears, and operating the vehicle.
        
     
    
        
            Fluid Checks:
        
        
            Guidance on checking essential fluids such as engine oil, coolant, brake fluid, and windshield washer fluid.
        
     
    
        
            Tire Pressure Monitoring:
        
        
            Explanation of the tire pressure monitoring system (TPMS) and how to check tire pressures.
        
     
    
        
            Refueling:
        
        
            Instructions on the correct type of fuel to use and the refueling process.
        
     
    
        
            Emergency Procedures:
        
        
            Information on what to do in case of breakdowns, flat tires, or other emergency situations.
        
     
    
        
            Locking And Unlocking:
        
        
            Details on using the remote key, central locking, and individual door locks.
        
     
    
        
            Parking And Storage:
        
        
            Guidance on proper parking techniques, including the parking brake, and recommendations for long-term storage.
        
     
    
        
            Maintenance Checks:
        
        
            Instructions for basic user-level checks like wiper blade inspection and light bulb replacement (where applicable).
        
     
    
        
            Resetting Service Indicators:
        
        
            Information on how to reset service reminders within the vehicle's iDrive system.
        
     
    
    
        
            Depth:
        
        
            Comprehensive owner-level information covering all operational aspects, safety features, and basic maintenance guidance. Not a service or repair manual, but provides essential knowledge for ownership.
        
     
 
    
    
    
        
            Transmission Type:
        
        
            6-Speed Manual Transmission (Getrag GS6-37BZ)
        
     
    
    
        
            Transmission Type:
        
        
            6-Speed Steptronic Automatic Transmission with Paddle Shifters
        
     
    
    
        
            Clutch:
        
        
            Hydraulically operated, single-plate dry clutch (Manual)
        
     
    
        
            Gear Ratios Manual:
        
        
            1st: 4.06, 2nd: 2.40, 3rd: 1.58, 4th: 1.19, 5th: 1.00, 6th: 0.87, Reverse: 3.54
        
     
    
        
            Gear Ratios Automatic:
        
        
            1st: 4.17, 2nd: 2.34, 3rd: 1.52, 4th: 1.14, 5th: 0.87, 6th: 0.69, Reverse: 3.40
        
     
    
        
            Final Drive Ratio:
        
        
            3.08:1
        
     
 
    
    
    
        
            Length:
        
        
            172.2 inches (4374 mm)
        
     
    
        
            Width:
        
        
            69.9 inches (1775 mm)
        
     
    
        
            Height:
        
        
            54.6 inches (1387 mm)
        
     
    
        
            Wheelbase:
        
        
            104.7 inches (2657 mm)
        
     
    
        
            Front Track:
        
        
            59.7 inches (1516 mm)
        
     
    
        
            Rear Track:
        
        
            60.3 inches (1532 mm)
        
     
    
    
        
            Curb Weight Manual:
        
        
            Approx. 3770 lbs (1710 kg)
        
     
    
        
            Curb Weight Automatic:
        
        
            Approx. 3836 lbs (1740 kg)
        
     
    
        
            Gross Vehicle Weight Rating:
        
        
            Approx. 4795 lbs (2175 kg)
        
     
    
    
        
            Cargo Volume Top Up:
        
        
            Approx. 12.0 cubic feet (340 Liters)
        
     
    
        
            Cargo Volume Top Down:
        
        
            Approx. 8.0 cubic feet (225 Liters)
        
     
 
    
    
    
        
            NHTSA Front Impact:
        
        
            5-Star Rating (for Coupe model, Convertible ratings may vary)
        
     
    
        
            IIHS Top Safety Pick:
        
        
            Likely awarded Top Safety Pick for its structural integrity and safety features.
        
     
    
    
        
            Dsc:
        
        
            Dynamic Stability Control (includes ABS, ASC, DTC, Cornering Brake Control)
        
     
    
        
            Traction Control:
        
        
            Automatic Stability Control and Traction (ASC+T)
        
     
    
        
            Brake Assist:
        
        
            Brake Assist (BA)
        
     
    
        
            Tire Pressure Monitoring:
        
        
            Tire Pressure Monitoring System (TPMS)
        
     
    
    
        
            Airbags:
        
        
            Front airbags, side-impact airbags (integrated into seats), head protection system (curtain airbags for front occupants).
        
     
    
        
            Seatbelts:
        
        
            Three-point inertia-reel seat belts with pretensioners and force limiters.
        
     
    
        
            Rollover Protection:
        
        
            Automatic pop-up rollover protection bars integrated behind the rear headrests.
        
     
    
        
            Child Seat Anchors:
        
        
            ISOFIX anchors for securing child safety seats.
        
     
 
    
    
    
    
        
            Display:
        
        
            Central LCD display with controller knob on the center console.
        
     
    
        
            Features:
        
        
            Navigation system (optional), Radio (AM/FM/HD), CD/DVD player, Bluetooth connectivity for hands-free calling and audio streaming, USB integration.
        
     
    
    
        
            Parking Assistance:
        
        
            Park Distance Control (PDC) - front and rear parking sensors (optional).
        
     
    
        
            Lighting Technology:
        
        
            Adaptive Headlights (optional) that pivot with steering.
        
     
    
    
        
            Bluetooth:
        
        
            Standard or optional depending on package, for phone and audio.
        
     
    
        
            Usb:
        
        
            Included in Premium Sound or Multimedia packages for audio playback and device charging/connectivity.
        
     
 
    
    
    
        
            Oil Change Interval:
        
        
            BMW Condition Based Service (CBS) system determines oil change intervals, typically around 10,000-15,000 miles or annually, whichever comes first.
        
     
    
        
            Brake Fluid Flush:
        
        
            Recommended every 2 years regardless of mileage.
        
     
    
        
            Coolant Change:
        
        
            Typically recommended at around 50,000-60,000 miles or 4-5 years for the initial change, then more frequently.
        
     
    
        
            Spark Plug Replacement:
        
        
            Recommended around 60,000 miles for the N55 engine.
        
     
    
    
        
            Engine Oil Spec:
        
        
            BMW Longlife-01 (LL-01) or BMW Longlife-01 FE (LL-01 FE) synthetic engine oil. Viscosity typically 5W-30 or 0W-40 depending on climate and specific LL rating.
        
     
    
        
            Coolant Spec:
        
        
            BMW Blue Antifreeze/Coolant (G48 ethylene glycol-based).
        
     
    
        
            Brake Fluid Spec:
        
        
            DOT 4 High Performance brake fluid.
        
     
    
        
            Transmission Fluid Manual:
        
        
            Typically a high-quality gear oil, such as Pentosin MTF LT-2 or equivalent, with specific viscosity requirements.
        
     
    
        
            Transmission Fluid Automatic:
        
        
            BMW ATF Dexron VI or approved equivalent.
        
     
    
        
            Differential Fluid Spec:
        
        
            BMW Hypoid Gear Oil G2 (SAF-XJ 75W-140 is common for M models, check for specific 135i requirements).
        
     
    
    
        
            N55 Engine Common Issues:
        
        
            Potential for water pump failure, ignition coil issues, and occasional turbocharger wastegate rattle. Early N55 models had a different fuel pump than later ones.
        
     
    
        
            Convertible Top Issues:
        
        
            Hydraulic pump or cylinder leaks for the convertible top, sensor failures affecting operation.
        
     
    
        
            Power Steering Issues:
        
        
            Leaks from the electric power steering assist system's hydraulic components.
        
     
    
        
            Valve Cover Gasket Leaks:
        
        
            Common on many BMW engines, including the N55, leading to oil leaks.
        
     
    
        
            Injectors:
        
        
            High-pressure fuel injectors can be a wear item on direct-injection engines.
        
     
 
    
    
    
        
            Brand Focus:
        
        
            BMW is renowned for its 'Ultimate Driving Machine' philosophy, emphasizing performance, handling, and driver engagement.
        
     
    
    
        
            1 Series Introduction:
        
        
            The BMW 1 Series was introduced globally in 2004 as a compact executive car, positioned as BMW's entry-level model. The E88 convertible variant was launched later.
        
     
    
        
            135I Positioning:
        
        
            The 135i represented the high-performance variant of the 1 Series convertible, offering a potent turbocharged engine and sport-tuned chassis.
        
     
    
        
            Generation:
        
        
            This 2010 model is part of the first generation 1 Series convertible (E88).
        
     
    
    
        
            Production Years:
        
        
            The E88 convertible was produced from 2008 to 2013.
        
     
    
        
            Manufacturing Location:
        
        
            Primarily manufactured in Germany.