Winter may seem a strange time to release a new convertible car, but if the United Kingdom's reputation for rain can't prevent it from being the best selling market for convertibles in Europe, perhaps the cold should not either. The Car Enthusiast tried out a new addition to the BMW 6-series range, the 650i Convertible, on a very fresh and windy day.

The BMW 650i slots in at the top of the Convertible range (the Coupe will shortly be available in 500bhp M6 guise, which we will be testing at the end of the year) and brings the same 4.8-litre, 367bhp V8 engine as used in the BMW 550i we drove recently. BMW expects the 650i to prove significantly quicker than the similarly engined BMW 550i due to weight saving in the form of composite front wings and aluminium bonnet. However, this is somewhat undone in the Convertible model with unladen weight increasing by a massive 210kg over the BMW 650i Coupe to 1,925kg. Maybe not so lightweight then.

Whatever you think of the Bangle styling, the Convertible is no babe amongst high-end drop-tops; the removal of the roof is not so successful from a styling viewpoint compared to the Coupe. Much of the problem would seem to be BMW's insistence on preserving a similar profile whether soft-folding or metal roof, yet at the same time demanding a glass rear screen that brings the advantage of proper demisting. With the slope of the Coupe rear screen, it would make stowing the hood away nigh on impossible, hence this is replaced with a small upright screen more reminiscent of the Ferrari 348/355 Spider (except that was plastic). Unfortunately styling wise this is less than a success.

Perhaps BMW should have followed the current vogue for folding metal rather than soft fabric, but in defence, the passenger area of the BMW 650i is so much greater than even the budget four-seat folding hard-top cars such as the Renault Megane and Peugeot 307CC, let alone the two seat only Mercedes SL range that is more likely to compete for the same buyers. The size of the roof and ensuing packaging nightmare justify the use of fabric in this case. To be fair to BMW, the fabric is of the highest quality, folds away electrically (of course) in a matter of seconds and when erect is still commendably low on wind noise.

Enough about the looks, once ensconced in the driver's seat you can't see the outside, unless you have a penchant for self-admiration while passing glass buildings. From the inside, the view is so much more appealing. Our car was swathed in leather, with brushed aluminium across the dash. As this is the Sport model, the 'wood' trim was in dark birch, which in my opinion is sportier than the usual brown wood used in luxury cars. The (optional) colour satellite navigation screen was placed high up and centrally, and was very clear even if the iDrive system to operate it remains as much fun as ever.

Moving off: first things first, it's a convertible, the roof must come down. Didn't matter that it was jacket and hat weather with rain threatening any moment, it's in the rules; you have to have the top down. Easier said than done, it took me a while to find the switch. Once found it was a matter of holding the button in while the electrics took over. At this point I spotted an advantage of the vertical rear window: before the roof folded it retracted into the bodywork, then with the roof fully stowed, up it came again to act as a wind deflector. And a pretty good wind deflector it would prove to be. As well as being wholly transparent (unlike most mesh wind deflectors), once off down the road it allowed just enough breeze to remind the occupants the roof was down, but not so much to turn them into Sideshow Bob clones.

There's no getting away from the fact that the BMW 650i is a big car. In convertible form it's also a very heavy car. That extra 210kg might not trouble the 367bhp engine too much (BMW claims it still does 0-62mph in 5.7 seconds rather than 5.4 seconds for the Coupe), but it's very noticeable when braking from speed that you are slowing a lot of car. The brakes still worked very well, it was just that you could feel the weight so much more and that brought on just that nagging, if unfounded, doubt that they might just be too marginal for comfort.

Ah, comfort. With four seats and all that weight, the 650i is more grand tourer than out and out sports car. So maybe you'd expect the chassis bias to be more on comfort than handling? Not on this car; maybe it was the 19-inch wheels that come as part of the Sport package, but the ride was just the wrong side of firm for my taste. Any long drive would be punctuated by reminders whenever the road surface wasn't flat. Great on the track I imagine, but this is a Grand Tourer, not a Touring Car. At least the payback was excellent handling of the goes-where-it's-pointed variety. With the optional 6-speed automatic gearbox protecting the drivetrain from too much abuse, and traction control there for additional security, good cross country progress could be made, if not quite as serenely as maybe a Jaguar would have gone. But that only brings us back to those brakes which were not so convincing under these cross country blast circumstances.

Unless you are willing to put up with the compromise, I would suggest not opting for the Sport version. Revel in the Grand Tourer nature of the car; blast across Europe at an indecent pace while snug and secure in that luxurious interior. And leave your friends at home; although a four seat car, the rears are more for children or occasional trips to the pub for lunch rather than carrying six-foot adults for hundreds of miles. For most people this will be just fine.

It might seem from the above that I didn't really like the BMW 650i, but that's not entirely true. The weight of the car heavily compromises any thoughts that this is a sports car. Any other 'sport' accoutrements are simply out of character and degrade what's left. What is left is a supreme way to travel, wafting along with the top down, isolated from the outside world. If you're in a hurry, buy the Coupe.