Cars

BMW's hit for 6

As relaxing as a spa and almost as large, BMW's 6 Series convertible is a wonderfully engineered car which comes with a sun tan as standard. It's hugely satisfying but isn't cheap, writes William Scholes

BMW 640d Convertible (2015)
BMW 640d Convertible (2015) BMW 640d Convertible (2015)

IT will likely come as no surprise if I tell you that BMW's 6 Series convertible is a lovely thing.

Just look at it. Big and imposing, with the same brooding car park presence as the All Blacks pack, lavishly equipped and with an oh-so-desirable soft-top, the big 6 is perfect for a grand tour.

Dropping into the seat, sliding behind the wheel and aiming the long, long bonnet down the road is enough to make you imagine that your next stop might be Cap-Ferrat and the Côte d'Azur - well, it's a better thought than the altogether grimmer reality of gridlock around Clifton Street and le dreaded terrain de Spruce on the M1 that I inflicted on the 6 Series.

It can't be called subtle, though. Like a Conservative Party fundraiser, it positively oozes cash, though perhaps not to the extent that it looks worth £80,000 - this is essentially a gentrified 5 Series, remember.

Even so, that price tag begins to justify itself when you discover just how supremely comfortable and relaxing the 6 Series is. An ESPA spa on wheels, few other cars deliver such a rewarding feel-good factor to driver and passengers.

Things get better when you drop the roof. Electrically operated, naturally, it folds flush into the rear deck in around 25 seconds.

For maximum look-at-me ability, it can go up and down on the move, at speeds of up to 25mph - perfect to take advantage of our late September Indian summer.

The roof itself is almost worth the entry price alone. Like all the best convertibles, it is a fabric affair, distinguished here by twin rear buttresses which presumably exist for no other reason than to show just how clever BMW's engineers are.

Between them is a little vertical rear window; it operates independently of the roof, sliding up and down as preferred, and serves as another glorious example of engineering overkill.

It is also a reminder of why BMW charges more for the convertible - by around £6,000 - than its sister two-door coupe and four-door Gran Coupe 6 Series models.

Whichever flavour of 6 Series you opt for, you get just about the most handsome model in BMW's current range, excepting the 5 Series estate and 4 Series Gran Coupe. The current generation of 6 arrived in 2011; it has just been facelifted, receiving some cosmetic and technical changes.

BMW says it took styling cues from racing yachts - car companies always say this sort of thing - but given its length and girth the 6 is less speedboat, more barge.

This doesn't translate into vast acres of room for all four passengers, however. In that respect, the 6 Series convertible is a bit of a reverse Tardis.

Front-seat passengers are extremely well catered for, but the back seats are best-suited for younger children - adults won't particularly appreciate being stowed amidships. The boot isn't massive either - a maximum of 350 litres with the roof up and 50 fewer with the roof stowed, accessed through a letterbox opening.

To be fair, convertibles with four proper seats are rare enough, and the 6 Series is one of the more accomplished - it is just that at 16ft long and almost 7ft wide, it doesn't seem unreasonable to expect a little more room.

Nor does the 6 ever really shake off the feeling that it is a size too big for Irish roads.

It doesn't shrink around the driver in the way that some other large sports cars do, reinforcing the impression that its natural forte is easy, relaxing cruising rather than give-and-take B-road blats.

The 6 Series can be ordered with a choice of three petrol engines and one diesel.

If you really must have petrol, a 3.0-litre six-cylinder 640i and 4.4-litre V8 650i are the saner options. At the top of the tree is the bonkers £100k M6, which is stupid-fast thanks to a 4.4-litre V8, twin-turbos, 552bhp, 502lb/ft and 0-62mph in 4.3 seconds.

But the diesel, badged 640d, is the rational choice because of its blend of economy and thrust.

Its tidal wave of 465lb/ft torque from low down the rev range is a perfect match for the car's cruising credentials and, being one of BMW's woofly 3.0-litre six-cylinder diesels, it even sounds pleasing.

And it is plenty quick enough - 0-62mph in 5.5 seconds and effortless in-gear acceleration see to that - and the prospect of 40mpg real world fuel consumption makes it hugely appealing.

As is the way with modern BMWs, there is a dizzying array of chassis and gearbox modes to play with; 'comfort' is all you need, really, though the sport modes are good fun too...

It's happiest in comfort mode, though. The 640d pours itself along the road in that silky fashion so typical of big, rear-drive BMWs. Engine and road noise is nicely suppressed.

Wind noise can be a problem for soft-tops when the roof is erect, but the 6 Series is barely troubled, occasionally raising itself to a gentle whisper. With the roof down, it is also one of the least buffeting convertibles I've driven - even back seat passengers, who usually get the full wind tunnel effect in four-seat soft-tops, don't have much to complain about.

Convertibles, particularly large four-seaters, are prone to what is called scuttle shake. A by-product of the loss of rigidity caused by lopping off the roof, it usually presents itself as a slight judder felt through the steering wheel on rough surfaces or bumps.

Although it hasn't been eliminated altogether, scuttle shake is remarkably suppressed in the 6 Series - a testament to just how thoroughly engineered and constructed the car is.

Other stand-out features on the car I drove include excellent seats, a head-up display and swanky digital instruments. BMW's iDrive control system, still among the best offered by any manufacturer, is present and correct, and the bird's eye view parking camera - which has to be seen to be believed, and mesmerises passengers - is a superb addition.

But my favourite was the trick LED headlamps. These adjust the lamps' throw according to speed, adapting how the light is distributed according to motorway or city conditions. The lights' beam also moves to help illuminate deep into curves as soon as the steering wheel is turned.

So clever are the BMW's lights that you can even have main beam on constantly - the car works out what portion of its beam it needs to redirect so that other drivers are not dazzled, whether they are in front or coming towards you. They are a brilliant safety aid.

Big, posh four-seater soft-tops are few and far between, which makes the BMW 6 Series convertible a big fish in a small pond.

Most convertibles around this price point are two-seaters - the Jaguar F-Type and Mercedes-Benz SL, for example - or have only token back seats, like the Porsche 911.

To find anything of comparable size with four seats means spending considerably more on something like a Maserati GranCabrio or Bentley Continental.

And that means that in a niche of one, the BMW 6 Series convertible reigns supreme - if you must have a big four-seat soft-top that doesn't cost six figures, it is your only choice.

That might sound like damning with faint praise, but it isn't meant to be.

The 6 Series is an accomplished car in its own right and manifestly so well engineered that it makes a strong case for itself; whether it is worth £80,000-plus is debatable, but there can be no argument that there are few nicer ways to travel than wafting along in a 6 Series convertible with the roof-down.

But you knew that as you looked at it, didn't you?