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Easygoing, comfortable BMW 420d convertible offers plenty, but its squidgy nature won't excite spirited drivers
Nic Cackett
7 March 2014

What is it?

We’ve already driven the range-topping BMW 435i convertible, now it’s the turn of the car which will make most of the volume - the 420d. Aside from the engine, this is much the same car; a lower, longer and wider prospect than the model it replaces, and one that continues to sport a retractable metal hard-top roof. 

From launch, the familiar 181bhp 2.0-litre unit will be the only diesel engine available with the convertible, and its frugality affords the car 55.4mpg economy and 133g/km CO2 emissions in conjunction with the six-speed manual gearbox. Select BMW’s eight-speed automatic, and they improve to 58.9mpg and 127g/km. 

There are five trim levels to choose from, starting with the SE sampled here (although not on UK roads). The mechanics of a life cycle change means the 420d ends up with more standard kit than its predecessor - including the current 3 Series’s large infotainment screen, iDrive controller, Drive Performance Control, 17-inch alloy wheels and heated front seats. 

The price difference is a modest £495. But that still sees the model start at £36,675 - almost £2500 more than the equivalent Audi A5 cabriolet 2.0 TDI SE. The example tested also featured a number of options - BMW’s Professional media system, 18-inch wheels, adaptive suspension - hiking its final total to £43,850. 

What's it like?

Much like the 435i - hardly short on quality, but overall a disappointment. The blame for this is not difficult to spread around. The bulk of it, appropriately and inevitably, must be placed on the vast, mechanism-festooned roof which barely fits in the boot and weighs the dynamic equivalent of a planet. 

Watching it slowly unfold from its overstuffed hiding place, a lengthy, 20-second process which plays out with with all the irksome methodicalness of an elderly scout leader opening a map, one wonders why BMW insisted on persevering with the three-piece tin-top. 

Its benefits are negligible - under it, the 420d is no more refined than a contemporary fabric roof - and the penalty unavoidable. 


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The 320d SE weighs 1495kg. The 420d SE weighs 1755kg. That extra burden is not easily hidden. The 435i buries it under 302bhp of straight-six concealer; the 420d, even with a healthy 280lb ft of torque available, is less able to do the same - especially when the four-cylinder engine’s well-known shortfall in refinement is taken into account. 

However, the vocal, gearknob-rattling motor is at least game; the suspension tune is not. 

BMW’s engineers have certainly beavered away underneath to shoulder the strain - ultra-stiff control arms and axle subframes have been slightly repositioned, pivot points adjusted, the camber angle and roll centre fine-tuned - but even in the most aggressive of its four modes (Sport+), the conspicuously doughy result never settles into quick progress like the 3 Series. 

Clearly, a more benign, agreeably cushioned car was the intention here, and driven in a manner more befitting a mobile sun lounger, the 420d is at least comfortable. 

Only the meanest of surfacing infringements will dial themselves into the seat backs, and the roof-down interior is acceptably blustery rather than tempestuous. But too much of the former flair is gone; push on, and the car can no longer push back. 

Should I buy one?

If buying a convertible is merely a four-up vanity exercise or a convenient way of keeping the comb-over flat, then the 420d’s newly inherited interior - typically first rate, easygoing attitude, solid residuals and likely very decent economy will certainly appeal, and duly make BMW’s entrant a match for its similarly fettled opposition in this segment. 

But the car feels even less like the current 3 Series than we expected, and in our book that’s more than just a shame. Just as the folding roof has been allowed to intrude on the model’s usable boot space (reducing it to just 220 litres - less than you’d get in a TT roadster) so has it mercilessly eroded the marvellous handling identity. 

That, above all else, is why the 320d is a five-star car - and why the 420d convertible certainly isn’t. 

BMW 420d convertible SE

Price £36,675; 0-62mph 8.2sec; Top speed 146mph; Economy 55.4mpg; CO2 133g/km; Kerb weight 1755kg; Engine 1995cc, 4 cyls, diesel; Power 181bhp at 4000rpm; Torque 280lb ft at 1750-2750rpm; Gearbox Six-speed manual

Join the debate


7 March 2014
I simply don't buy the clichéd and lazy "poseur - mid-life crisis" arguments wheeled out whenever convertibles are tested. What an open-top brings is another element to car driving. For most people, the simple joy of driving along in the open is enough, and that's fine. For car and in particular driving enthusiast however, the convertible experience should add to and not interfere with the driving experience. That's why this BMW convertible is so disappointing. I'm a big fan of BMW 3 and 5 series cars and drive a 3 series daily for work. The essence of a BMW is its steering and handling with decent performance which is why, on the basis of the reviews so far, this car is a complete disappointment. The new 3 and 4 series cars are handsome and well proportioned rather than beautiful cars but this looks clumsy and ill-proportioned. A cloth roof may have fixed things. Chance missed - if you want a convertible that doesn't handle you'll probably now go to Audi.

7 March 2014
I'm with you Fox Terrier... I've had five 3 series models over last 18 years, including my favourite E36 M sport convertible - fabulous to drive, good looking, refined and roomy (and critically has a reasonable boot). I love driving, but also love the open air - I just don't want to accept such compromises as the E9x and F3x convertibles bring.
For info - I currently drive a 1 series convertible - nice car, but just too small overall, and not a replacement for the 3 series.
I really hoped the F30 generation would have featured a cloth roof, and thus not suffer the huge weight penalty and boot compromises that a folding metal roof brings. The forthcoming 2 series is promising but alas is just too small for 4 adults and luggage... so ultimately, and with great sadness, I may have to look away from BMW.

7 March 2014
tested with the caveat "keen drivers will be disappointed". A brace of ugly cars that arent good to drive - even the good to drive cars need thousands of pounds worth of electronic extras adding before they are considered to drive like a BMW should. Losing their mojo.

7 March 2014
Autocar wrote:

The 320d SE weighs 1495kg. The 420d SE weighs 1755kg.

Ouch!! And why doesn't this new car use the new B47 aluminium 20d engine with 190PS?

7 March 2014
"its squidy nature won't excite spirited drivers".

I'm not a very spirited driver and even I don't like my cars to be 'squidy'. I've had a few that have squirted black substances when frightened and that messed up all sorts of driving, even the slowest and most laid-back. This report might not even be accurate: I can't believe that a new BMW 420d convertible would do such a thing. Maybe the reviewer means the car is an invertebrate or has very long tentacles with suckers. I can't see the latter - are they an option? Maybe he means that these BMWs are occasionally attacked and eaten by sperm whales: now that really would be a reason not to buy one.

7 March 2014
Another mediocre BMW hits the salesfloor. It used to be easy to sell BMWs. When I bought my first in 1995 the salesman simply let me drive the car and I was sold. 10 BMWs later I will not be buying another. The NA straight sixes have gone,.Rear wheel drive is on its way out now the 2 Series van with windows is out. The company is trying to expand "the brand" by diluting all the qualities that made BMW great - quality (taken a nose dive after the E39 and E46); the handling (why do you need to add £000s to buy the "proper" suspension set up?); the engines (rough rattly 4 cylinder diesels and turbo petrols instead of silky smooth straight sixes) and exclusivity (now every photocopier repairman drives a 318d or 320d why go with the herd?). Of the 10 BMWs I have owned my favourite was aan E46 325i SE convertible. It was solid not floppy, it handled well, it sounded great and the boot was practical even with the roof down. Why? It had a cloth roof not a stupid folding hard roof. Less weight, more compact and no rattles or squeaks from the seals and scaffolding in the boot. It is very sad to see a marque that can engender fierce loyalty declining this way. BMW need to remember fleet managers do not buy BMWs 10 times over 19 years. As soon as Kia or Ford or VW or anyone has a lower cost per mile they will buy their cars instead. But the "well heeled" private buyers will have gone by the time BMW realise that put off by rubbish build, rough engines, poor ride and stupidly high prices.

7 March 2014
Sorry but are there really that many idiots out there that will chuck such a massive chunk of fabricated paper for an overweight rattle box? If the gearnob ratlles and its noisy from the business department, then in heavens name what will happen in 24 months after the cover folds and the hood doesnt? Anyone buying this heap needs to visit the soft box

7 March 2014
Right up to the point when you turn the key and realise in a convertible the only sensible choice of engine is petrol powered.
So glad I was able to buy such a car with a turbo petrol engine, soft top & paddle shift gearbox when Saab still had some available in the 9-3.

7 March 2014 a 320d and drive along with your head out of the window. That way u get all the joys of wind in ur hair motoring, you're driving a decent car and you got a ton of cash left in ur wallet.

7 March 2014
I couldn't buy a diesel conviertable!! Especially in a 4 cylinder format. Just idling away would annoy me.

For looks this is pretty BMW, but I think a purchase can only be a 6 cylinder.

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