2018 BMW 6 Series Convertible

in Compact convertibles
2018 MODEL

$86,700 - $101,300


Overall Rating




Ever since the time the BMW 6 series returned back from its sabbatical about a decade ago, the 640i convertible has enjoyed a top position in the market and at the price point there aren't many others competing with it. The direct competitors, the Porsche drop top 911 Carrera and the Mercedes-Benz S-class convertible are significantly expensive.

Even with a price of around $90,000, the BMW 6 series gives it's much more expensive counterparts a run for their money in all the major department. Powered with a 3.0L I6 twin-turbocharged engine, it generates about 315 hp at 5800 rpm and 330 lb-ftof torque at 1400 rpm, figures which easily match its rivals.

See detailed review »


Lovely interiors

Fantastic Powertrain

Strategic pricing

Fuel economy


Harsh ride quality

Unresponsive Steering

Low Headroom

What's New?

2018 BMW 6-Series convertible doesn't offer anything extraordinary from the previous versions


vehicle bio

base price



2dr Convertible

passenger capacity


top speed

130 mph



engine type


182 cu. in.


315 hp @ 5800 rpm


330 lb.-ft. @ 1400 rpm


8-speed automatic


brake rotors (f/r)

11.8 in. ventilated disc brakes/12.3 in. ventilated disc brakes



112.4 in.


192.8 in.


74.6 in.


53.7 in.

curb weight

4250 lbs.

ground clearance

4.8 in.


passenger volume

89 cu ft.

cargo volume

11 cu ft.

payload capacity

772 lbs.


zero to 60 mph

5.3 sec.

standing ¼-mile

14 sec.

fuel economy


20/23/29 mpg

highway range

536.5 mi.


basic warranty

4 years/50000 miles

drivetrain warranty

4 years/50000 miles

corrosion warranty

12 years/unlimited

roadside assistance



 2018 BMW 6 Series Convertible in Ruby Black Metallic color  2018 BMW 6 Series Convertible in Jet Black color  2018 BMW 6 Series Convertible in Glacier Silver Metallic color  2018 BMW 6 Series Convertible in Carbon Black Metallic color  2018 BMW 6 Series Convertible in Alpine White color
Ruby Black Metallic

Vehicle images are guides only and may not reflect the model's exact specifications/features– exact specifications/features should be confirmed with the seller.








Fuel Economy








Variant Name


 2018 BMW 6 Series Convertible 640i


Fuel: Premium unleaded (required), Transmission: Manual, Seats: 4


640i 2dr Convertible (3.0L 6cyl Turbo 8A)
Engine: I-6 Transmission: 8A
Drivetrain: RWD MPG: (20/23/29)
Torque: 330 lbs.-ft. @ 1,400 rpm

 2018 BMW 6 Series Convertible 640i xDrive

640i xDrive

Fuel: Premium unleaded (required), Transmission: Manual, Seats: 4


640i xDrive 2dr Convertible AWD (3.0L 6cyl Turbo 8A)
Engine: I-6 Transmission: 8A
Drivetrain: AWD MPG: (19/22/28)
Torque: 330 lbs.-ft. @ 1,400 rpm

 2018 BMW 6 Series Convertible 650i


Fuel: Premium unleaded (required), Transmission: Manual, Seats: 4


650i 2dr Convertible (4.4L 8cyl Turbo 8A)
Engine: V-8 Transmission: 8A
Drivetrain: RWD MPG: (17/20/25)
Torque: 480 lbs.-ft. @ 1,750 rpm

 2018 BMW 6 Series Convertible 650i xDrive

650i xDrive

Fuel: Premium unleaded (required), Transmission: Manual, Seats: 4


650i xDrive 2dr Convertible AWD (4.4L 8cyl Turbo 8A)
Engine: V-8 Transmission: 8A
Drivetrain: AWD MPG: (16/19/25)
Torque: 480 lbs.-ft. @ 1,750 rpm

Expert Review

carhp editor October 26, 2018


Overall Rating





Fuel Economy






Powered with a 3.0L I6 twin turbocharged engine, it generates about 315hp at 5800rpm and 330lb-ft at 1400rpm, figures which easily matches its rivals. However, the pickup of this machine and harsh riding quality is something where it lags behind.



The BMW 640i Convertible is available in two versions: the 640i Convertible and the 650i Convertible. The front-engine, rear-wheel-drive, 4-passenger, 2-door convertible is powered by a 3.0L I6 twin turbo charged engine, with 8 speed automatic transmission as standard.

Trim 640i convertible 650i convertible
MSRP $86,700 $98,300



Automatic w/Driver Control Ride Control Adaptive Suspension 105-Amp/Hr Maintenance-Free Battery w/Run Down Protection
Electric Power-Assist Speed-Sensing Steering Regenerative 210 Amp Alternator
Cell Phone Pre-Wiring 600w Premium Amplifier
Wheels w/Machined w/Painted Accents Accents Aluminum Wheels w/Machined w/Painted Accents Accents
Power Convertible Top w/Lining, Glass Rear Window, Automatic Roll-Over Protection and Manual Wind BlockerEngine Auto Stop-Start Feature

Gas-Pressurized Shock Absorbers

Audio Theft Deterrent Radio: AM/FM Stereo CD/MP3 Player
Radio: AM/FM Stereo CD/MP3 Player Chrome Side Windows Trim
Hi-Fi Sound System Window Grid Diversity Antenna
SiriusXM Satellite Radio w/1 Year All Access Enhanced USB & Bluetooth

Once the version has been selected, the buyer can choose between the two trims, one which is significantly expensive than the other.

We Recommend

Between the two, the 650i is the obvious choice. Not just you get a bigger engine but also a variety of features which makes the 6 series a luxury grand tourer. You get extra seat adjustability, All-wheel-drive, and better sound system. 



The 2018 BMW 6 Series prioritizes comfort over sporty handling. Nevertheless, most drivers will enjoy the driving experience. - Edmunds

Engine and Transmission

The BMW 640i convertible is powered by a 3.0L I6 turbocharged Engine at produces 315hp and 330lb-ft, which provides rear wheel drive with 8-speed automatic transmission as standard.

Models 640i convertible Porsche 911 carrera cabriolet Mercedes Benz SL 450
MSRP $86,700 $103,400 $88,200
Engine 3.0L l6 3.0L l6 3.0L l6
Transmission 8-speed automatic 7-speed manual 9-speed automatic
Horsepower 315 hp @ 5800 rpm 370 hp @ 6500 rpm 362 hp @ 5500 rpm
Torque 330 lb-ft @ 1400 rpm 331 lb-ft @ 1700 rpm 369 lb-ft @ 2000 rpm

All the three, the BMW convertible, the 911 Carrera and the SL 450 are powered by the same 3.0L I6 engine which produces similar figures of torque and horsepower as well with the 640i being the cheapest and followed by the 911 Carrera and the SL 450.


The 8-speed automatic transmission takes a beating here as the 640i is the slowest of the blocks in the bracket of 0-60MPH. However, the acceleration is smooth and gives a tough fight to its competitors in the other departments.

Models 640i convertible Porsche 911 carrera cabriolet Mercedes Benz SL 450
0-60 MPH 5.5 4.6 4.9
Quarter mile 14.0 N/A 13.2
Engine 3.0 L 3.0 L 3.0 L
Emission (Tons/yr of CO2 Emissions @ 15K mi/year) 7.7 7.7 7.6

In this particular scenario, the SL 450 is the one which is a direct rival to the 640i convertible as it beats the BMW in the 0-60mph parameter. However, it is the BMW which wins in the Quarter mile.

The Porsche 911 Carrera was way ahead of the other two in the 0-60mph department, but came level in the other parameter.

Handling and Steering

If there is one parameter where the BMW scores over its rivals, it is the drive quality, and the Convertible didn't disappoint. The steering is a bit lackluster, but it is not touch much a worry.

As it being a rear wheel drive, the BMW is agile along the corners and responds well with the all season tires.


The BMW 640i convertible has the brakes which matches its acceleration. Despite being one with the heaviest car with a curb weight of 4,255 lbs, the brakes results are pretty decent.

Model 640i convertible Porsche 911 carrera cabriolet Mercedes Benz SL 450
Brake Front (in.) 13.7 13.0 14.2
Brake Rear (in.) 13.6 13.0 12.6
Curb Weight (lbs.) 4,255 3,307 3,826
60-0 MPH (ft.) N/A N/A N/A

The Porsche 911 being the lightest, it gives the best braking results amongst the three, closely followed by the Mercedes SL 450. The good part is that the rear and the front brakes give comparable value. However, considering the BMW being the cheapest, these are great figures.

Fuel Economy


Being the heaviest amongst the three, it is naturally expected for the BMW 640i convertible to give the worst figures under this parameter and with a city mpg of 20 and highway mpg of 23, it does pretty well.

Model 640i convertible Porsche 911 carrera cabriolet Mercedes Benz SL 450
MPG (city) 20 20 20
MPG (highway) 29 29 28
MPG (combined) 23 23 23

However, the lightest 911 and the SL 450 follow closely behind, with somewhat equivalent figures of 20 mpg in the city and 29 and 28 mpg on the highway respectively.



With premium materials everywhere, exquisite fit and finish, wood or carbon-fiber accents, a high-end audio system and supremely comfortable driver's seat, BMW’s 2018 6 Series leaves a lasting impression. - KBB

While the previous 640i had decent interior design, the new 640i has one of the best cabins in this range. The classic BMW analog and gauges gives it a premium feel. And with a touch screen infointment system, it makes the cabin experience, one with the highest quality.

Seating and Comfort

The BMW 640i is a two row cruiser which accommodates 4 people. It provides heated and cooled seating as well. The passenger rear seats are also electrically powered. The driver's seat is a bit hard but that shouldn't be much of an issue.

Model 640i convertible Porsche 911 carrera cabriolet Mercedes Benz SL 450
Passenger capacity 4 4 2
Front (Head/Shoulder/Leg) (In.) 40.3/56.9/42.1 N/A 39.1/55.5/42.9
Second (Head/Shoulder/Leg) (In.) 36.5/49.6/30.5 N/A N/A

The seats are electronically powered providing ample support to the driver. They are made of premium synthetic leather upholstery. Add to that leather wrapped steering wheel that can be adjusted to the preference and provides all wheel steering drive.

Interior Features

  • Cruise Control
  • Vehicle Anti-Theft System
  • Fog Lamps
  • Keyless Start
  • Steering Wheel Controls
  • Driver Vanity Mirror
  • Power steering

Infotainment System

The BMW 6-series infotainment system is easy to use, once you clear the first curve. It provides a premium sound system and a smart integration device. Add to that a WiFi hotspot, and it provides a great package.

  • AM/FM Stereo
  • Auxiliary Audio Input
  • MP3 Player
  • Satellite Radio
  • Smart Device Integration

Cargo Volume

The Convertible has a spacious trunk. There is no load lip to lift up the baggages. The storage spaces are excellent with a 12V socket as well. The rear seats are foldable leading to extra room.

Model 640i convertible Porsche 911 carrera cabriolet Mercedes Benz SL 450
Cargo Volume with 2nd row up (ft.3) 11.0 5.6 13.5

The Mercedes SL 450 is a direct competitor in this parameter. With a volume of 2.5 ft3 more than that of the BMW, it is clear winner. However, the Porsche lags far behind.



The recently redesigned nose on the 2018 BMW 6 Series is subtly effective, with the number of vertical bars in each "kidney" now nine instead of 10. The rear end looks menacing when viewed head-on, which is just as it should be. - KBB

This BMW cruiser has had a minor facelift from its 2016 version. It has a sharp nose and a tail end which looks smooth and luxurious. It now has one less vertical bar on the grill (now nine) .This is done along with tweaks to the fog lamps and the lower air intake. The Grand coupe adds up to 4.5 inches of length which facilitates its two rear doors. Its arch line roof gives it a sporting look with not so decent head room at the rear. With a ground clearance of 4.8 inches, it does provide adequate room to drive over the off-roading track as well.

Dimension and Weight

As mentioned, the new facelift version makes the 640i look more stylish and supreme than its previous versions. Add to that, it is one of the heaviest cruisers available in the market.

Model 640i convertible Porsche 911 carrera cabriolet Mercedes Benz SL 450
Curb weight (lbs.) 4,255 3,307 3,826
Length(in) 192.8 177.1 182.3
Width(in) 74.6 71.2 82.6
Height(in) 53.7 50.7 51.2
Ground clearance (in) 4.8 N/A 3.7
Wheelbase (in) 112.4 96.5 101.7
Track width (in) F/R 63.0/65.2 60.7/59.8 62.8/63.0

The BMW is about 10 inches longer than the Mercedes. The highest ground clearance shows it's off road nature. Although not as wide as the Mercedes, it has no impact on the passenger seating capacity.

Exterior Features

Some of the exterior features include:

  • Convertible Soft top
  • Rear Defrost
  • LED Headlights
  • 18-inches Alloy wheels
  • Power adjusted side mirrors


The IIHS and the NHTSA have not yet rated the BME 640i Convertible.

Safety Features

The various safety features in the BMW 640i Convertible are:

  • DSC III Electronic Stability Control (ESC)
  • ABS And Driveline Traction Control
  • Dual Stage Driver And Passenger Seat-Mounted Side Airbags
  • First Aid Kit
  • Traction Control
  • Electronic stability control


Porsche 911 Carrera vs BMW 6-Series

The BMW has far more advantages than the Porsche 911 Carrera. Both the cars have the same engine capacity, it is however the automatic version of the BMW which pips the Porsche here because of its ease to drive. The BMW also has a far more spacious trunk than the Porsche with a capacity of 11.o ft3 to that of 5.6 ft3 of the Porsche.

The BMW is also a taller, longer and wider car than the Porsche with a slightly better fuel economy than the latter. Thus, the BMW 640i convertible is a clear winner in this comparison.

Mercedes-Benz SL 450 vs BMW 6-Series 

The fight between the BMW and the Mercedes-Benz goes right down to the wire. Both generate almost equal figures in the engine capacity and the fuel economy. The cargo capacity is also almost equal.

However, the BMW is a longer car than the SL 450 and can house 4 passengers as that of 2 in the Mercedes-Benz, Thus emerging as a clear winner.

Final Verdict

The 2018 BMW 640i may be a cheaper option than the Mercedes-Benz and the Porsche, It is nothing short of a true BMW experience. It gives the sporty feel, is luxurious from the inside and has a peppy drive quality to it.

However, all is not great with this car. The 0-60mph pickup is much less than the Porsche and the Mercedes-Benz. It is heavier than the other two.

But this can be covered by its better fuel economy and the luxurious experience. All in all, if you have the money, the Porsche 911 Carrera is a much better bet, however if someone is looking for a cheaper option, there is no parameter where the BMW 640i convertible lag too far behind.

Top Cars

2018 Audi A5 Convertible
2018 Mercedes-Benz AMG C 63 Convertible