Road Test: BMW 640i Convertible

Ray Leathern thought all four-seater convertibles were flawed. Turns out he just hadn’t driven the right one.

Now that I’ve had my go in the BMW 6-Series Convertible I’m thinking there might actually be something to this whole four-seater convertible thing, although it’s still not perfect by any stretch. First of all, the 6-Series is the size of luxury liner – glorious, if a little vulgar all at once. It’s soft top, folding roof looks like it’s been modelled on something from Zoolander’s ‘Derelicte,’ fashion campaign, and being a BMW you get as many admiring glances as Bernie Madoff at a retirement annuity meeting. However, once you set off on a journey, its crisp and tactile BMW-ness can’t help but pin prick holes in the whole experience.

And this BMW 640i isn’t even the top of the pops V8 powered 650i. The 640i comes with BMW’s Twin Power, 3.0-litre straight six motor that’s won International Engine of the Year for goodness knows how long now. And that’s fine by me because in my opinion, a BMW should have a kidney grille upfront, a six cylinder engine just behind it, and rear wheel drive at the back, the end. The 640i, thanks to its clever turbo system, puts out 235 kW and 450 Nm, which can launch it to 100 km/h in 5.7 seconds and all the way to a top speed of 250 km/h, and still only consume 7.9 L/100km of fuel and produce 189g/km CO2. A set of quite frankly astonishing figures when you realise the 640i weighs just shy of two tons.

Then we must tackle the issue of stiffness and rigidity…, any big convertible’s Achilles heal. I have driven the Audi S5 Convertible and a Mercedes Benz E500 Cabriolet, and not a word of a lie, both of them came within inches of throwing me off a mountain… the same mountain in fact and almost at exactly the same place. Massive power, big, four-seater convertibles just aren’t meant to work when driven with venom. The lack of rigidity from no roof and only a floor connecting you and the power between each corner of the car means a massive disconnect between all the componentry keeping you on the black stuff. Not allied at all by a comfort bias in the suspensions that are afforded most convertibles. A damper at the back left is doing its level best to dampen the vehicle over a bump, while the front right is doing the same nanoseconds later, however, due to a convertibles flex in the chassis, by the time these signals have travelled their way back through the steel and aluminium, to the driver, it’s far too late to know what actually happened underneath you in the first place, and the car is trying to settle itself over a whole new set of bumps and cambers. Throw big power into the mix, from a heavy engine way out in front, and the resultant effect is you either almost get spat off the side of a mountain, or you must back off the pace… in which case why have a powerful convertible in the first place?

Well, that’s the departure point at least, and that’s where the 640i starts to volley a few spikes back your way. You put the roof down and expose yourself to a typical boulevard cruise… fine. The BMW’s ride quality is supple and effortless and you’re the numero-uno yacht captain. After you’ve posed your way down the strip, a few corners approach, you slip it into ‘Sport Mode,’ almost as a token gesture, what the hell, but the car hunkers down, tightens up through the throttle and steering… ‘allo there. You tip it into the first corner and the front grabs hard onto the road, the BMW’s rear tyres are steadfast too, which is rather amazing considering they’re so far behind they’re still back on the main strip, posing.

Okay, it’s time to ask a little more of this thing, so you slip it into ‘Sport+ Mode,’ which will let the rear almost all the way loose of its electronic shackles. Oh my word, the balance, the poise, the accurate response from the power delivery at the rear. I don’t know how the 640i does it, with nothing but seven billion kilometres of air connecting the roof to the front and back, but it is sublime to drive and it makes the most of ever kW and Nm on offer. Of course that was on a super smooth coastal road, so I had to take it, sharpish, to a less smooth mountain one to see how it coped with some more challenging undulations, and… it did that road just as well.

So there you have it, the BMW 640i delivers thrill a minute driving responses, has a great six cylinder soundtrack from the world’s best, mass produced engine currently made, and all while being the king of al-fresco, high street posing. What more could you ask for from a car? Nothing quite frankly… It’s been a while since I’ve driven a car that made driving such a delight.

What we like…

• Sports car handling despite it being a convertible and as long as a yacht.
• Six cylinder engine delivers everything: power, torque, economy, soundtrack.
• Brilliantly comfortable and hi-tech interior with all the bells and whistles.

What we would like…

• Some of the detailing and styling makes it look seriously Ponzi scheme-ish.
• A better cloth roof, it looks ugly and isn’t as good as the Audi S5’s.
• It’s not exactly what you’d call cheap… and that’s before you start on the options.

Ray Leathern has been test driving and critiquing cars for four years now. He is South Africa’s 2010 Motoring Journalist of the Year in the magazine category, as well as a member of SA’s 2011 Car of the Year jury. What Ray writes, we read, and we suggest you do too.

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