BMW 330d Convertible M Sport

It's a little known fact that the first BMW was a convertible. The 1928 Dixi 3/15 was an Austin Seven built under licence. Since then, many open-top cars have worn the blue propeller badge, but the 3-Series Convertible is the most successful.

First sold in 1986, it arguably invented the compact executive drop-top market, and has remained a class leader ever since. However, the latest version brought with it one of the most significant changes in the model’s history – a folding metal hood.

While coupé-cabrios are all the rage, does the hard roof layout compromise the 3-Series? Before taking the wheel, we would probably have said no. But the BMW has no ordinary set-up. Rather than a normal two-piece top, the lid splits into three – giving designers more freedom to style the rear of the car to accommodate the panels. What’s more, watching the top fold is a delight. The key design brief was to avoid the bulbous tail from which many coupé-cabrios suffer. The styling team has succeeded, but the flat rear deck comes at the expense of boot space.

With the hood stowed, luggage room is 50 litres down on the previous-generation fabric-roofed cabrio, at 210 litres – and the space is awkwardly shaped, too. Yet the BMW has a trick up its sleeve called Boot Access. Press a button in the load area, and the roof panels rise up to widen the opening.

The roomy rear seats can be folded to form a practical second luggage space, but they don’t drop to give hatch-style access to the boot. A ski hatch facility which allows you to carry long items is a £145 option.

Take a seat in the front of the 3-Series, and the mix of inward sloping windows, a rakish screen and an effective wind deflector mean it’s impressively refined on the move. With the top down, the BMW recorded the lowest noise figures in this test.

It demands few compromises from the chassis, either. The body doesn’t twist when cornering and there’s no shaking around the A-pillars. All you have to put up with is a bit of vibration through the wheel; otherwise, the Convertible retains the usual 3-Series traits of sharp, communicative steering, strong brakes and a near-perfect handling balance.

So it’s great to drive. But cruising comfort is a more important consideration for any drop-top – and the BMW scores well here, too. The 3-Series is composed and offers a super-smooth ride.

The punchy and refined diesel proves convertible oil-burners are well worth a look. Add enviable desirability, and the 330d is one of the strongest drop-tops in any class.

Details

Price: £39,765
Model tested: BMW 330d Convertible M Sport
WHY: Potent diesel engine and stunning metal roof make the 3-Series worthy of inclusion.

Economy

Diesel power is the 330d’s big advantage as it keeps expenses to a minimum, even considering the rising price of diesel. Average annual fuel costs will be £1,753 – the cheapest of the four cars here – while emissions sit in the 25 per cent bracket. BMW’s fixed-price servicing deal contributes to the excellent 55.6 per cent residual value. So, once you’ve got over the £40,000 price tag, the hard-top 3-Series will be a reasonably cost-effective car to own.