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Driven: BMW M850i Convertible. Image by BMW.

Driven: BMW M850i Convertible
Having sampled the M Performance 8 Series, its hard to know why youd need any more speed than this. But then, will an 840d satisfy you as much?


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BMW M850i Convertible xDrive

4 4 4 4 4

Good points: looks great, nice interior, sounds superb, astonishing performance, capable handling

Not so good: cramped in the rear considering its size, plain-looking cabin, it's expensive, we prefer the 'regular' Eight as the more relaxed 840d Coupe

Key Facts

Model tested: BMW M850i Convertible xDrive
Price: 8 Series Convertible range from 78,840, M850i Convertible from 105,285, car as tested 121,165
Engine: 4.4-litre twin-turbocharged V8 petrol
Transmission: eight-speed Steptronic auto, xDrive all-wheel drive
Body style: two-door GT convertible
CO2 emissions: 229g/km if registered before April 6, 2020 (VED Band 226-255: 1,815 in year one, then 465 per annum years two-six of ownership, then 145 annually thereafter); 246g/km if registered after April 6, 2020 - but VED remains the same either way
Combined economy: 28.2mpg
Top speed: 155mph (limited)
0-62mph: 3.9 seconds
Power: 530hp at 5,500-6,000rpm
Torque: 750Nm at 1,800-4,600rpm
Boot space: 350 litres (hood up), 280 litres (hood down)

Our view:

Having had a BMW 840d Coupe earlier in the year and loved it, we thought we'd flip things for our next Eight experience, by going for the other two-door body style in the form of the Convertible and with the whole lot powered by the thunderous 4.4-litre biturbo V8 petrol engine of the M850i. So, a 530hp open-top grand tourer with the ability to hit 62mph from rest in less than four seconds and the promise of a lovely, burbly eight-pot soundtrack - this should be heaven, right?

Well, it is, to a degree. There's no doubting the 8 Series remains, by some distance, the best-looking modern BMW of the lot and lopping its roof off proves no exception to this rule. For a 4.8-metre-long, 1.9m-wide car that weighs in at 2,090kg, the Beemer still manages to convey an air of sportiness rather than hulking great mass, while proportionally there are no heavy flanks nor sagging design lines on it. It looks equally good hood up or down, and while some may lament the overly-fussy front end, we just think it is terrific to behold.

The cabin's also very nice, if not quite as dramatic or all-round pleasing as the exterior. BMW interiors are starting to look the same nowadays from entry-level to flagship and no amount of crystal-glass, '8'-branded gearlevers (going under the option name of 'Crafted Clarity' and costing 575), M-striped seatbelts (260) or Piano Black BMW Individual dash trim (250) is going to elevate this passenger compartment to a level where it can hope to compete with something like a Bentley Continental GTC, sadly.

It's not without merit, of course. Ergonomically, it's fabulous and the equipment levels are pretty generous as standard, but those digital dials in the cluster won't please everyone, with the 'reversed' rev counter and sometimes difficult-to-read/operate graphics, while if you choose the M850i Convertible's interior in black on black on black then it's quite a sombre affair - with nothing to tell you that you're in the M Performance derivative bar another one of those BMW steering wheels that has a weight issue; seriously, we remember many, many years ago having a lengthy product debriefing with a BMW designer who said they'd spent ages deliberating over whether their contemporary steering wheel had 1-, 2- or 3mm of padding, and they decided 2mm was absolutely ideal, striking precisely the right balance between premium feel and (no laughing at the back) hand comfort. At some point in the intervening period, apparently a wadding thickness of 34mm suddenly became the accepted norm within the halls of Munich. And it's just not right.

The 8 Series soft-top is also, like its Coupe sibling, not the most accommodating in the rear passenger seats, so it remains a 2+2 rather than a genuine four-seater, although the M850i Convertible must be commended for having a decent boot. BMW's decision to stick with a fabric top, rather than a folding metal hairpiece, means there's a clever fold-up/fold-down storage system in the cargo area for the hood, which only saps 70 litres from the capacity when you want to cruise around enjoying the weather. Keep the roof of the Eight in place and fold the stowage 'box' away, and the boot is a thoroughly decent size and shape, measuring 350 litres all in. So it should do grand touring duties for two with a serious amount of aplomb.

To drive, it's a far grander car than any 6 Series Convertible which has gone before it. The way it smothers both road and wind noise is remarkably proficient, even with the M850i's hood folded down, whereupon occupant buffeting is kept to a minimum courtesy of clever aerodynamic fettling by BMW. The drivetrain is exceptional at simple day-to-day driving duties, being murmur-quiet in operation and glitch-free in terms of the smoothness of the power delivery and management of traction, but light that 4.4 V8 up and you'll be in no doubt just how potent this car is. Mammoth outputs of 530hp and 750Nm make a mockery of the bulk of the M850i, while xDrive traction ensures almost maximal grip-and-go in all conditions (it takes a SERIOUS amount of provocation to make the Beemer's TCS/DSC lights flash in the dry if you've got the systems engaged) to fire the Convertible forward with incredible sharpness. Yet it's the noise which wins the day, because the related 4.4 V8 in some of the full-on M products doesn't sound as good as this; the F90 M5, for example, is positively dull to listen to in comparison. This is a facet of the M850i which brings its own questions about the audio qualities of the M8 Competition...

But that's conjecture on the part of this reviewer at this stage, so rest assured that the M850i sounds the nuts and goes like holy stink. It also handles decently well considering its vast size, with perhaps too-weighty steering that is lacking in feel being its one main dynamic bugbear. The rest of it, like its variable suspension (1,895 Adaptive M Suspension Professional), monster brakes and strengthened underpinnings to prevent scuttle-shake and torsional flex, can be said to 'tick all the right boxes' of fast-road driving. When you want the M850i to cruise, it cruises serenely like the best of GTs; and when you want it to go barrelling down a quiet back road with a degree of engagement and excitement that should befit a BMW wearing the letter M and those three stripes (even if it's an M Performance car, not an out-and-out M), then it can do that too.

Indeed, we spent a fortnight with the M850i and did nearly 530 miles in it, so much were we enjoying its company. It did all types of roads and driving in that time, with its best fuel economy return of 31.8mpg being quite incredible for a powerful, heavy, four-wheel-drive petrol V8 like this. But that exalted number was achieved on a steady motorway cruise from the southern reaches of Herefordshire to central Nottinghamshire; its overall return of 22.7mpg across those 527 miles rather tells a different story of how juicy this 8 Series can be.

Which brings us to a somewhat awkward conclusion. There's no doubt the M850i Convertible is a fantastic big grand-touring soft-top, a car which has a wide breadth of talents and which will instil immense desire in many who behold it. But, for us, it feels a bit stuck between two stools. Yes, you can argue that it's all the performance (and then some) you could ever reasonably need and so it might undo the case for an M8, but we'd go the other way - the 840d, capable of in excess of 50mpg on a cruise and something we got 42.2mpg out of during a week at the wheel (admittedly, the wheel of a lighter, more aerodynamic Coupe), is all the GT you could ever need. Plus it's cheaper, it feels no less involving to be at the wheel of it when tackling a challenging road and the cabin is absolutely no different in terms of ambience if you spec the right options.

Factor in the price of our test M850i, inflated from an already-robust 105,285 to a breath-taking 121,165 by the addition of the options already outlined, as well as 1,500 on BMW Laserlights, 2,800 on the Technology Package (Driving Assistant Professional and Parking Assistant Plus bundled together), 1,300 on the Premium Package (soft-close doors, ventilated front seats and the Heat Comfort Package of heated armrests and neck-warmers up front), 3,500 on the Bowers & Wilkins Diamond Surround Sound System and 3,350 on an M Carbon Exterior Package, and what you have here is an expensive car which you can't imagine anyone picking over and above the similar-money M8, unless they're really, really interested in the best exhaust note. Because the M8 will drive even better than the M850i; in fact, the M8 does drive better than the M850i, according to boss-man Shane who's the only one on the team to have yet driven the 625hp 8 Series.

So it's a marvellous car, the M850i Convertible xDrive, it truly is. But there's also the slight suspicion that, despite its undoubted brilliance, it's probably surplus to requirements in the exceptional 8 Series range.


Bentley Continental GTC: interior finishing is several leagues above that of the BMW and Bentley has sharpened up the Conti soft-top's chassis act, too. It's mighty pricey, though.

Ferrari Portofino: so quick and expensive that it's more of a rival for an M8, but Ferrari would convince you that the Portofino is a GT sports convertible. Superb to drive, although the steering is very sharp.

Mercedes-Benz S 560 Cabriolet: less power and a less focused chassis from the Merc, but an AMG engine in disguise plays all the right tunes, while the ride comfort and interior quality are both ahead of the same features on the M850i.

Matt Robinson - 20 Aug 2019    - BMW road tests
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2019 BMW M850i Convertible UK test. Image by BMW.2019 BMW M850i Convertible UK test. Image by BMW.2019 BMW M850i Convertible UK test. Image by BMW.2019 BMW M850i Convertible UK test. Image by BMW.2019 BMW M850i Convertible UK test. Image by BMW.

2019 BMW M850i Convertible UK test. Image by BMW.2019 BMW M850i Convertible UK test. Image by BMW.2019 BMW M850i Convertible UK test. Image by BMW.2019 BMW M850i Convertible UK test. Image by BMW.2019 BMW M850i Convertible UK test. Image by BMW.


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