BMW 8 Series Convertible review

Cars like the BMW 8 Series Convertible provide a real tonic for the soul. With one on your drive, the prospect of getting away from it all is literally on the doorstep: just grab the keys, drop the top and hit the road for somewhere with bluer skies and greener grass.

At the heart of the 8 Series Convertible is a platform that combines high-strength steel, aluminium, magnesium and carbonfibre-reinforced plastic, all with the aim of keeping weight down but structural stiffness high. Not that this is a sports car – although BMW likes to call itself the 'Ultimate Driving Machine' manufacturer, the 8 Series has a large footprint.

That moves it away from sports models such as the Porsche 911 Cabriolet towards the luxury end of the market, where you’ll find 2+2 convertibles such as the Bentley Continental GT Convertible, the Lexus LC 500 Convertible and the Mercedes-AMG SL. 

As with its tin-topped sibling the BMW 8 Series it's available with a six-cylinder petrol engine that sends its power to the rear wheels, or a thumping great V8 that powers all four wheels. The V8 in particular is prodigiously quick, but if you really must have the fastest drop-top BMW on sale, see our BMW M8 review. 

Before you do that, though, stick with us – we reckon the ‘regular’ BMW 8 Series Convertible might be all the car you ever need. Over the next few pages of this review, we’ll tell you exactly which version we'd recommend, and also walk you through how it compares with rival convertible cars you might be considering. 

Once you've picked the right model for you, remember we can help you find it for the lowest price if you search our New Car Deals pages. They list lots of the best new convertible car deals.

Eagle-eyed BMW fans might have noticed that, despite using the same engine as the BMW M5 performance saloon, the 8 Series Convertible in M850i form doesn’t have quite as much power. In effect, the engine has been detuned, but that shouldn’t necessarily come as a disappointment.

The 4.4-litre twin-turbo V8 still feels immensely flexible and impressively refined in a way that entirely befits an open-topped grand tourer. It’s smooth and relatively quick to respond to accelerator inputs, with only a short delay between pressing the pedal and feeling the turbos spin up and blasting you down the road.

So, not only is it effortless to drive but, with the added traction of xDrive four-wheel drive, you can also deploy all 523bhp with virtually no drama when the road opens up. If we had one complaint, it would be that the M850i’s engine note isn’t quite as mellifluous as the V8 in the similarly-priced Lexus LC 500 Convertible.

We haven't yet driven the entry-level petrol 840i, which has rear-wheel drive rather than four-wheel drive, but objectively, the M850i is the engine to go for. (If you want an even more powerful version, see our BMW M8 review.)

We’ve no complaints about the model's cruising manners. With the roof up, there's a bit of road noise and some faint wind whistle at 70mph, but it’s nearly as refined as the hardtop BMW 8 Series. And while it doesn’t quite deliver the stately progress of the significantly more expensive Bentley Continental GT Convertible it does produce much less wind and road noise than the Mercedes-AMG SL. 

With the top down, the wind deflector does a great job at keeping your hair in place, and it’s possible to hold a conversation, even at motorway speeds. Just as impressive is the car’s rigidity. It takes a very rough surface to get the body flexing, and even then, you’ll only ever see the slightest tremors in the rear-view mirror. That’s not the case in the Continental GT or LC 500 Convertible – potholes and raised metalwork cause their bodies to shudder noticeably.

The 8 Series is quite firm for a luxury convertible so it's not as supple over speed bump as a Continental GT or LC 500 and fails to waft as well as them on motorways.

With four-wheel steering, a clever traction-boosting ‘eDiff’ on the rear axle (standard on the M850i) and the optional M Adaptive anti-roll bars fitted to our test car, it feels much nimbler than it looks. Granted, the steering doesn’t tell you a great deal about what’s happening between the tyres and the road, but you can still make surprisingly quick progress, with plenty of grip and traction. 

It’s certainly more fun for keen drivers than a Continental GT Convertible, although those looking for proper sports car thrills should look at the Porsche 911 Cabriolet.

After you’ve absorbed the sleek exterior of the 8 Series Convertible, with its flowing profile and taut surfaces, you might expect the interior to be equally dramatic. Instead, you’ll find an agreeable interior that feels a lot like a plusher BMW 5 Series. In terms of visual panache it falls some way behind the Bentley Continental GT Convertible, the Lexus LC 500 Convertible and the Mercedes-AMG SL

That said, BMW has always focused on restrained visual designs, preferring outright build quality to showiness. It’s here that the 8 Series scores highly, and from the precise stitching on its leather dashboard to the numerous brushed chrome trim pieces, everything looks and feels well honed and tactile.

There's good news when it comes to the infotainment system, too: BMW’s latest-generation iDrive, with a 12.3in touchscreen, is currently the best on the market. It's responsive, mostly intuitive and one of the easiest systems to operate on the move, thanks to a rotary controller that supplements the touchscreen. Android Auto and Apple CarPlay smartphone mirroring come as standard. 

Another 12.3in screen for the digital instrument display is standard across the range, showing maps and media where they're easy to see. Plus, you get a head-up display that projects your speed on to the windscreen.

You feel quite submerged in the 8 Series, thanks to its low seating position and high window line. The seats are comfortable and there's lots of adjustment to allow you to get comfortable, but it can be tricky to see out in all directions. Don't worry, though: you get front and rear parking sensors, a rear-view camera and, for night-time driving, LED headlights as standard (BMW's Laserlights are available as an option).

There’s loads of space in the front of the BMW 8 Series Convertible, with plenty of head and leg room for a couple of tall adults, and enough width for occupants to sprawl out.

However, there’s very little leg room in the rear. In fact, we’d go so far as to say that the rear seats are better suited to a couple of weekend bags than they are to humans.

The boot is a reasonable size, with 350 litres of space, so you'll fit in a few small suitcases, but it's too shallow for anything bulky. That said, the boot in the Lexus LC 500 Convertible is even smaller, so try the Bentley Continental GT Convertible if you need to carry a set of golf clubs.

The BMW 8 Series sits at the premium end of the convertible car market, so it's not cheap, but it's not bad value relative to its rivals. Even the top-end M850i, for example, is significantly cheaper than the equivalent Mercedes-AMG SL 55 and Bentley Continental GT Convertible while the 840i massively undercuts the Porsche 911 Cabriolet. That said, if you’re after a V8-engined luxury convertible then the Lexus LC 500 Convertible is superb value for money. 

You won’t need to add many options, but you can still go to town adding extras if you want to. All models have two-zone climate control, leather seats, power-folding door mirrors and heated seats. You can also add heated armrests, a heated steering wheel and much, much more.

The M850i adds a sports exhaust system, lightweight 20in wheels and the M Sport differential for added cornering traction. All models get a wind deflector and BMW’s Air Collars, which are integrated into the front head restraints and provide a stream of heated air to warm your neck when the roof is down.

Sadly, the 840d diesel has been discontinued. We loved it for its fantastic fuel efficiency and low down grunt. However, you could argue that the revvier six-cylinder petrol engine in the 840i suits the character of a relatively sporty convertible. It’s also reasonably frugal: at a cruise you can expect around 35mpg. That’s far more palatable than the mid 20s you’ll experience in the M850i. 

The 8 Series hasn’t been crash-tested by Euro NCAP but it has a broad suite of active safety aids, such as automatic emergency braking (AEB), lane-keeping assistance and blind-spot warning, to help keep you safe.

The 8 Series Convertible wasn’t included in the 2022 What Car? Reliability Survey but BMW as a brand finished 16th out of the 32 manufacturers rated. That puts it above Porsche in joint 19th and Mercedes in joint 23rd but way behind Lexus in first place (Bentley didn't feature). A three-year, unlimited mileage warranty is provided as standard.

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