BMW 8 Series Convertible Review 2023

Written by Andrew Brady

8/10
heycar ratingImposing fresh-air grand tourer
  • 2019
  • Convertible
  • Petrol, Diesel

Quick overview

Pros

  • Offers surprising value for money, despite its high price
  • Handsome styling and convertible roof
  • Standard equipment will impress gadget geeks

Cons

  • Pricier rivals do luxury motoring better
  • Rear seats are virtually useless for adults
  • M850i not as involving as true sports cars

Overall verdict on the BMW 8 Series Convertible

"If only the best will do, then perhaps BMW’s flagship 8 Series Convertible model is the right car for your driveway. The open-top version of the 8 Series certainly makes a pitch for being one of the grandest tourers around."

BMW 8 Series Convertible Review 2023: Exterior Front

At first glance, the large front grille of the BMW 8 Series Convertible certainly demands your attention, while the rest of the bodywork is carved with strong lines and angles. When it comes to looks alone, we reckon it's up there with the best convertibles.


It looks genuinely handsome when the roof is dropped while with the roof up, it matches the coupe version in profile. But should you buy one? Find out in our BMW 8 Series Convertible review.


Despite its rather grand size, the BMW 8 Series Convertible is a four-seater. While the rear bench does have room for two, it’s best suited to occasional use. Cramming adults back there for long periods of time may result in a mutiny. Instead, think of the seats as an extension of the boot and for use by humans only in an emergency. 


Forget ideas of clunky folding metal roofs, as the BMW 8 Series Convertible uses a fabric soft-top. It opens or closes in an impressive 15 seconds. You can even drop the top at speeds up to 31mph, should you want to create some theatre in traffic. 


The boot can hold 350 litres when the roof is up, dropping to 280 litres with it down. That might come as a shock, given the overall size of the BMW 8 Series Convertible. It should hold enough luggage for a few nights away, at least, and you can open the boot lid automatically using your foot. 


Given the type of cars the BMW 8 Series Convertible is up against, BMW knows it has to deliver on the driving front. The BMW 8 Series Convertible will handle twisty roads far better than you may initially think, feeling much smaller on the move thanks to clever technology. The payoff for such athleticism is a ride that feels a little firm when you just want to cruise along. 


BMW offers the 8 Series Convertible with a choice of two petrol engines and one diesel. An eight-speed automatic gearbox is standard on all versions, while the diesel 840d and range-topping M850i come with four-wheel drive.


All of the engines offer decent power and progress, allowing the BMW 8 Series Convertible to cover long distances with ease. Consider the diesel version if you spend a lot of time munching miles on the motorway, with up to 40mpg possible.


As a flagship model, the BMW 8 Series Convertible is packed full of technology. A huge multimedia screen lives at the top of the dashboard and the instrument gauges have been replaced with a digital display. Dual-zone climate control, a head-up display, adaptive LED headlights and neck-warming air vents are included. 


Not everyone needs, or even wants, a huge cabriolet like this. But the BMW 8 Series Convertible manages to make a compelling case for those who do. Striking looks, strong performance and a host of futuristic tech make it very hard to ignore.


Looking for a used car for sale? We've got 100s of BMW Approved Used Cars for Sale for you to choose from, including a wide range of BMW 8 Series Convertible cars for sale. If you want the hard top version, you need our BMW 8 Series Coupe review.

BMW’s 8 Series Convertible should appeal to those who want an impressive open-top tourer that still offers a degree of driving fun. It delivers on comfortable cruising and demolishing long distances, yet is still entertaining on back roads. 


Not everyone can have an entire fleet of cars to suit their every need. As an all-rounder, the 8 Series Convertible has an advantage over cars like the Porsche 911. It’s pricing also makes it appear a bargain next to flashier rivals. The only limitation are the rear seats. If you want your luxury convertible to be a true four-seater, the 8 Series is not the car for you.


If you decide you don't need the soft top, there's the BMW 8 Series Coupe plus the more practical four-door BMW 8 Series Gran Coupe

BMW has made the 8 Series Convertible range helpfully simple to understand, with just three cars on offer. Choosing between the petrol 840i and diesel 840d is dependent on how many long-distance miles you are likely to cover. If you like to rack up motorway journeys on a regular basis, the diesel 840d will deliver the benefit of respectable fuel economy


Otherwise, the entry-level 840i is likely to deliver all the performance necessary. It also comes with a wealth of standard equipment, and is (relatively) affordable. 


Although the M850i may appeal on paper, the BMW M8 Competition Convertible does a better job of delivering outright performance. It leaves the M850i looking a little hamstrung, and harder to justify over the cheaper 840i petrol and 840d diesel.

Closest in scale and attitude to the BMW 8 Series Convertible is the Mercedes-Benz S-Class Cabriolet. Like the 8 Series, it is a premium German grand tourer, but one that costs substantially more. However, the interior of the Mercedes is even plusher and more feature-packed than the BMW. 


Likewise, prices for the Bentley Continental GTC begin at more than twice the cost of the basic 8 Series Convertible. Yet it does deliver a premium ownership experience deserving of the Bentley badge, along with thundering performance. An Aston Martin DB11 is similar in spirit, but again at a much higher price. 


This all leaves the BMW 8 Series Convertible in a class virtually of its own, given how it is priced versus rivals.

Comfort and design: BMW 8 Series Convertible interior

"If you have just stepped out of an SUV, the low-slung driving position of the BMW 8 Series Convertible will take some adjustment. The car sits very low to the floor, with the window line wrapping high around the driver and passenger. It’s not too claustrophobic with the roof up, however, and does emphasise the sporting bias of the 8 Series."

BMW 8 Series Convertible Review 2023: Interior

All models come with electrically-adjustable leather seats in the front. These offer plenty of adjustment for height, lumbar, and backrest angle. BMW also includes a steering wheel that adjusts electrically for reach and height, further allowing drivers to tailor their perfect seating position.


The front seats are heated, and come fitted with BMW’s Air Collar system. This works by blowing air across the back of your neck, helping you feel warm even with the roof down in colder weather. 


For maximum comfort with the roof down, BMW does supply a wind deflector as standard for the 8 Series Convertible. It does work well, but is a manually-operated affair that sits across the back seats, preventing them from being used. As a bonus, it does fold away to fit inside the boot. 


Compared to fancier rivals, the interior is smart and functional, if not filled with dramatic design touches. Everything feels logical to use, but a Mercedes-Benz S-Class or Bentley Continental feels fancier by comparison. 


Yet this does nothing to detract from the comfort of the BMW 8 Series Convertible. Drivers can feel safe knowing this big soft-top will cover long distances – then leave them feeling refreshed after they arrive.

BMW prefers to ensure its interiors are solid and well put together, if not the most inspiring places to look at. The 8 Series Convertible follows this approach, with a high-quality cabin that appears somewhat similar to cars lower down the range.


It feels very much classic BMW, with a sweeping dashboard slightly angled towards the driver, plus a large multimedia screen sat on top. There are still physical buttons for functions like the air conditioning, but many other settings are controlled through the iDrive system. 


Leather covers much of the interior, with the remaining plastic and metal parts all feeling expensive to touch. Stainless steel trim is fitted as standard, with carbon fibre or grey wood available as a cost option. 


Diving further into the options list finds ways to make the cabin of the 8 Series fancier. A ‘Crafted Clarity’ cut glass gear shifter can be added, making the lever look like it’s made from crystal. Extended Merino leather upholstery for the seats is also suitably plush. You can even have heated armrests.


While the additional extras might sound tempting, the standard interior of the BMW 8 Series Convertible is more than sufficient in terms of quality. Save your money and enjoy the feel of the car as it comes.

As the flagship of the BMW range, the 8 Series Convertible is absolutely packed with technology. Much of this is controlled via an impressive 10.25-inch touchscreen, controlling one of the best infotainment systems around. 


The system can also be operated through gestures, voice commands and a more traditional rotary controller. It incorporates BMW’s Intelligent Personal Assistant, allowing you to ask questions and give verbal commands, similar to systems used on smartphones.


A Harman Kardon surround-sound audio system is standard on the BMW 8 Series Convertible. It allows music to be streamed via Bluetooth or USB, and also permits wireless charging of smartphones. Satellite navigation is fitted, with live updates for traffic. 


Apple CarPlay is standard, although BMW does not offer support for Android Auto. This is disappointing when Android smartphones can be used to act as a ‘smart key’ for the BMW 8 Series Convertible. 


Directly ahead of the driver is a 12.3-inch digital instrument cluster, which replaces the usual analogue gauges. This can be used to display commands from the navigation system, along with other configurable information. A head-up display – also standard – can project your speed onto the windscreen.

Key to being a good grand tourer is offering those onboard room to feel truly comfortable. The BMW 8 Series Convertible manages this with relative ease for those in the front, but anyone in the back may feel less content. 


The driver and front-seat passenger have plenty of room. There are door pockets for storing smaller items, along with a cubby inside the centre console. 


Despite measuring 4851mm in length, 2137mm in width and 1345mm in height, the BMW 8 Series Convertible is really a four-seater in name only. Should you want an 8 Series that carries more than two people, the four-door Gran Coupe is a better bet. 


It’s also worth noting that the wind deflector, if deployed, straddles the space across the rear seats. So it’s maybe best to take the hint from BMW, and use the 8 Series Convertible’s rear bench as an extension of its boot.


BMW does at least fit folding rear seats, allowing longer items to be slotted through from the boot. The shape of the boot narrows the further it gets from the bumper, meaning you may have to be clever with your packing. 


Keep the soft-top roof in place and the 8 Series Convertible has room for 350 litres of luggage. That’s 70 litres less than the 8 Series coupe. As with most convertibles, dropping the roof means the folding mechanism eats into luggage space. Go topless and you will be able to store just 280 litres of junk in the trunk. 


The boot lid can at least be opened hands-free. This works by waving your foot under a sensor beneath the rear bumper, thus popping the lid open. There are storage nets for smaller items just inside the boot, too.


Given the limited storage space, BMW does not supply a spare wheel. Instead, buyers of the 840i and 840d feature run-flat tyres to ease you gently to a garage in the event of a puncture. The M850i comes with a repair kit instead.

Handling and ride quality: What is the BMW 8 Series Convertible like to drive?

"Transforming a car into a convertible typically means a compromise when it comes to how it rides and handles. Thanks to a combination of special materials and clever design, however, BMW is confident the 8 Series Convertible is almost identical to the coupe."

BMW 8 Series Convertible Review 2023: Driving Back

So are we. Opting for the BMW 8 Series Convertible doesn’t mean you will feel short-changed when it comes to tackling corners or cruising in comfort. This is still a big car, though, and the changes need to make the Convertible as stiff as the BMW 8 Series coupe have added weight. 


As a result, the BMW 8 Series Convertible is reliant on technology to help mask its bulk. This includes four-wheel steering on the 840d and M850i, which acts to make the car feel more nimble at speed. Factor in the light but precise steering, and the 8 Series can start to emulate ‘proper’ sports cars. 


There are limits, however. Technology can only do so much to fight physics, and cars like the Porsche 911 will always feel ultimately more involving to drive.


Sporting intent also brings a stiffer ride compared to rivals like the Mercedes-Benz S-Class or Bentley Continental GTC. Adaptive suspension allows some control over how firm the BMW 8 Series Convertible feels, but it never quite delivers a full dose of luxury. Standard 20-inch wheels with low-profile tyres don’t help, either. 


While the BMW 8 Series Convertible never feels uncomfortable, the tautness also makes it slightly tense on the motorway. This falls back to the 8 Series trying to be both a grand tourer and sports car at the same time. 


That the BMW 8 Series Convertible can almost deliver both is still impressive, especially at the price BMW asks for it.

The choice of engines for the BMW 8 Series Convertible is simple to explain. With just two petrol options and a solitary diesel, things are pretty straightforward. 


Petrol versions begin with the 840i sDrive. Using a 3.0-litre turbocharged straight-six, this engine produces a respectable 340 PS. It allows the 8 Series to accelerate from 0-60mph in 5.3 seconds, offering a pace similar to hot hatchbacks. It appeals more to the cruising nature of the car, but certainly isn’t slow. 


Like all 8 Series models, the 840i sDrive comes with an eight-speed automatic transmission. The gearbox shifts rapidly, and can use GPS data to preempt the best gear selection, based on what lies ahead. 


The petrol M850i xDrive makes a considerable leap forward in power. Some 530PS is developed by the 4.4-litre twin-turbocharged V8, placing it within serious performance car territory. Standard four-wheel drive also aids acceleration, seeing it reach 62 mph in just 3.9 seconds. 


Such ability is admirable, but leaves the M850i feeling marooned between the regular 840i and the hardcore BMW M8 Convertible. 


Diesel fans are limited to just one engine in the BMW 8 Series Convertible. Thankfully, the 320PS 840d xDrive matches the big drop-top machine well. It offers respectable performance, with 0-62 mph taking 5.2 seconds. It also has plenty of low-down torque, helping offset the relative bulk of the 8 Series Convertible. 


Those doing longer journeys should not fear picking the BMW 840d Comvertible, which comes with four-wheel drive as standard.

It may be caught between trying to be a sports car and a grand tourer, but the BMW 8 Series Convertible fulfills the brief of providing refinement and comfort very well. 


The roof is a fabric soft-top, albeit a seriously well-engineered one. With the hood up, sounds from the outside are almost as well muffled as you would find in the coupe version. 


Using the wind deflector aids the level of refinement when roof-down. It prevents almost all draughts in the cabin, meaning both you – and your hairstyle – should arrive unflustered.


Dropping the roof in the M850i is encouraged, even if just to revel in its exhaust noise. Making use of a standard sports exhaust, it sounds truly magnificent as it bellows along. It is likely to become an addictive habit, although your bank balance might not thank you for it.


The regular petrol 840i sounds good, if not as theatrical as the M850i. Even the diesel 840d avoids the normal stereotypes of tractor-like clattering, sounding refined and smooth. 


The stiff construction and big wheels of the 8 Series do transmit some vibrations back into the cabin. These are relatively low-level, and most should find the 8 Series Convertible a calming environment. 

The BMW 8 Series Convertible has not been submitted to Euro NCAP for crash testing, but almost all recent BMW models gained the full five stars when evaluated. There is little reason to suspect the large and high-tech 8 Series would not do the same. 


Six airbags are provided in total, including ones for the knees of the driver and front seat passenger. Roll-over protection is included, with roll bars that deploy automatically should the car sense it is about to flip upside down. 


Front and rear parking sensors are fitted as standard to all models, combined with a rear-view camera and park assist to help fit into the tightest of spaces. Given the limited visibility from the rear of the 8 Series, these are very welcome. 


Bright adaptive LED headlights are standard, with even brighter laser headlights available from the extensive options list. High-beam assistance is also included, helping you avoid dazzling oncoming cars by accident. 


Dynamic stability control and traction control help control the power from the engine, with the 840i and M850i gaining a trick M Sport performance rear differential. Huge M Sport brakes are also fitted to all models, measuring a massive 19-inches in diameter on the M850i.


Child seats can be fitted to the diminutive rear seats, with Isofix attachments included.


Tyre pressure monitoring is fitted as standard, and the 840i and 840d feature run-flat tyres. The M850i does without run-flat tyres, but has a puncture repair kit instead.

MPG and fuel costs: What does a BMW 8 Series Convertible cost to run? 

"Fuel economy and costs are likely to be relatively low priorities for anyone buying a grand tourer at this level. Still, for the BMW 8 Series Convertible owner who likes to save fuel, there are options available."

BMW 8 Series Convertible Review 2023: Exterior Back

The diesel BMW 840d Comvertible is the most efficient of all, capable of up to 40.4 mpg. Given the sheer mass of the car, this is a respectable performance and would suit drivers who regularly cover long distances. 


Using the petrol BMW 840i Convertible gently can see it achieve up to 33.2 mpg. This compares to hot hatchbacks, rather than large GT cars, with economy aided in part by the standard eight-speed gearbox. 


Forget hopes of sipping fuel with the BMW M850i Convertible, though. Officially it can achieve 24.8 mpg, but expect this to drop much lower should you insist on using all that performance. And we would insist.

The BMW 8 Series is relatively new so it's hard to say how it will perform in terms of long term reliability. It features a lot of advanced technology and systems which are great when they work, but can be complex and expensive to repair when they go wrong. 


BMW came 20th out of 30 manufacturers in the latest HonestJohn.co.uk Satisfaction Index with an overall satisfaction rating of 86.9%. 

It’s unlikely that anyone will be considering a BMW 8 Series Convertible as their first car, and it naturally appeals to more experienced drivers. All three models will be pricey to insure, but there are minor differences. 


The petrol BMW 840i Convertible is the version with the lowest insurance group, being rated at 48. That is still very high, considering there are 50 groups and reflects the overall prestige and performance of the 8 Series Convertible. 


Both the 840d and M850i are rated as insurance group 50 – the highest possible group.

Recent changes to VED (road tax) rates mean the BMW 8 Series Convertible has moved from ‘costly’ to ‘very expensive’. 


The cheapest model to tax is the BMW 840i sDrive Convertible petrol, with models registered before April 2020 owing a first year rate of £540. Tax for the following five years is £475 a year, partly due to the list price being above £40,000. 


A BMW 840i Convertible registered after March 2020 will now attract a first-year rate of £1305.


Buy an M850i registered after March 2020 and the first-year payment will be an eye watering £2175, compared to £1850 levied on cars registered before this date.


The 8 Series Convertible might not be the first choice as a company car. However, should it be on your fleet list, all versions attract a Benefit In Kind rate of 37%.

How much should you be paying for a used BMW 8 Series Convertible?

"As a high-end car that is relatively new to the market, overall volumes of used BMW 8 Series Convertibles are low."

BMW 8 Series Convertible Review 2023: Driving Side

Examples of the BMW 840i sDrive Convertible make up the majority of the cars currently available on the used market. Prices begin from around £54,000, which should secure a two-year-old car with less than 15,000 miles on the clock. This compares to a list price of £86,475 for the BMW 840i Convertible when new. 


Diesel BMW 840d Convertible versions of a similar age and mileage can be found from £57,500, while the rare BMW M850i Convertible will require closer to £75,000 for a nearly-new example.

BMW has kept the trim levels for the 8 Series Convertible simple, choosing to focus on a range of option packages instead. 


The BMW 840i Convertible and BMW 840d Convertible come with a wide array of standard equipment. Dual-zone climate control, adaptive LED headlights, parking sensors, a rear-view camera and BMW’s impressive 10.25-inch touchscreen multimedia display are included. 


Black Merino leather sports seats are fitted from the factory, and they are heated in the front. The Air Collar neck heating function is also included for the front seats, along with multi-way electric adjustment. It leaves the lesser two cars comprehensively equipped, meaning the M850i is there solely for those wanting more power. 


Moving to the BMW M850i Convertible brings, along with the bellowing V8 engine, a new front bumper with an additional lip spoiler. The front grille, wing mirrors, side vents, and model badging also gain a special Cerium Grey finish, complemented by 20-inch Y-Spoke alloy wheels.

Ask the heycar experts: common questions

Like the BMW 4 Series Convertible, the BMW 8 Series is fitted with a fabric folding roof, not a hardtop. It opens or closes in just 15 seconds and you can even drop the top at speeds up to 31mph if it starts raining when you're in traffic.
The BMW 8 Series is relatively new so it's hard to say how it will perform in terms of long term reliability. It features a lot of advanced technology and systems which are great when they work, but can be complex and expensive to repair when they go wrong.
The BMW M8 is the high performance version of the BMW 8 Series, so while it shares much, what makes it stand out is the 4.4-litre V8 twin turbo engine with 625PS as well as 20-inch alloy wheels, dual exhausts and an M Sport rear spoiler.

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