BMW 4 Series Convertible 2014 Review

BMW is rolling out the 4 Series Convertible in three variants: the diesel-engined 420d and the petrol 428i and 435i. All three variants are powered by turbocharged engines, with two of them being four-cylinder powerplants and the third – in the 435i – a six. All three drive to the rear wheels through a ZF eight-speed automatic. This transmission provides silky shifting whether the BMW Drive Experience control is set to Comfort or Sport. BMW does offer the option of a six-speed manual, but none were on the test fleet for the drive program.

Pricing ranges from $88,800 (plus on-road costs) for the 420d right up to $126,600 (plus ORCs) for the 435i, with the 428i slotting in between the two at $97,500 (plus ORCs). Standard equipment across the range comprises: cruise control, front and rear parking sensors, reversing camera, bi-xenon headlights, an electrochromatic mirror, rain-sensing wipers, auto-on/off headlights, leather upholstery, climate control, electric front seating adjustment with position memory, front-seat heating, leather-bound multi-function steering wheel, Bluetooth with audio streaming, USB/iPod connectivity and trip computer.

The 420d features a six-speaker audio system and 18-inch alloy wheels, while the 428i runs on 19-inch alloys and features adaptive suspension, anti-dazzle exterior mirrors, electric lumbar adjustment and a nine-speaker audio system. At the pinnacle of the range, the 435i gains variable sport steering, aerodynamic body kit, anthracite headlining, keyless entry, puddle lighting, Air collar, shift paddles and a Harman/Kardon 12-speaker audio system.

BMW is also offering buyers the Sport, Modern and Luxury trim lines at no charge for the 420d and 428i. These lines offer different wheel designs and a different cosmetic look to suit varying tastes. One thing is likely, however, few will find the 4 Series a boring design, even in its 'vanilla' state.

Styling can be a hit-and-miss affair at times. In the post-Bangle era at BMW the frequent hits have been punctuated by the occasional miss, but the 4 Series certainly finds its mark. The styling around the C pillars and rear flanks is better proportioned than the 3 Series convertible's, to my eye. Yet the 4 Series package retains a semblance of practicality.

Gaining access to the rear seat was much easier than in the E93 3 Series Convertible, although the motorised front seats were slow to move the seats forward or aft. Once in the back, there was plenty of head- and knee room for adults of average size. There's a ski-port that allows passengers to remain seated in the rear, or the whole rear seat squab can fold in one piece for through-loading of larger objects from the boot. By operating a special loading feature that raises the lowered roof in the boot by 40cm, users can load larger, bulky items (even a surfboard, it is suggested) through into the cabin.

Convertibles are normally 'limited' by their focus on the emotional needs of one or perhaps two people – even in a four-seater like this BMW. So the accommodation in the rear was welcome, but didn't detract from the front seats, which were inviting in all three variants. The driving position is typical of BMW design in recent years. Most controls fall easily to hand (other than the indicator/wiper stalks), and the instruments are readily legible.

On the move, noise was subdued in the 4 Series Convertible with the roof raised. The engines were very refined; there was some tyre noise penetrating the cabin, despite the insulating qualities of the folding roof. Even the base model 420d comes equipped as standard with a windblocker, which unfortunately we had no opportunity to try. It's a clever device that is easily removed and has a release on the driver's side to open up like a reverse-facing lid over the rear seats for stowage of items that won't fit in the boot. In other markets the windblocker can be folded up and stowed behind the rear seat, but the Australian Design Rule governing ISOFIX installation precludes that facility from being made available here, since the top-tether anchorage points fill part of the space required behind the rear seat squab.

BMW claims that torsional rigidity for the 4 Series Convertible is 40 per cent better than was the case for the 3 Series (E93) Convertible. It certainly feels a pretty rigid platform on the road – certainly better than a competitor driven during the same week – but the 3 Series sedan is naturally tauter still. Rollover protection is a large, U-shaped hoop that rises within 200 milliseconds behind the rear seat in the event the car flip. Configured this way, the hoop leaves enough room for the larger through-loading aperture behind the rear seat and saves 15kg in weight.

As for the driving impressions, the 4 Series does what BMW fanciers will ask of it. Steering is precise and responsive, matching the car's formidable grip and composed handling. On the flip side of the coin, the ride quality was never unduly sharp or harsh, whether set to Comfort or Sport mode in BMW's Drive Experience facility.

The least sporty of the new 4 Series Convertible range, the 420d would come closer to the mark if it were the 425d – with the same sequential-turbo engine introduced with the X5. As it is, the diesel '4' is a B+ effort, rather than worthy of an A grade.

Where the 420d felt more a cruiser than a bruiser, both the petrol engines delivered a significantly stronger sense of drama and urgency. The 435i with its twin-scroll turbo six was as crisp and clinically clean-revving as any BMW six you would care to name, but for me the 428i is the pick of the bunch. There's a rich, mellow engine note from the turbocharged four-cylinder, combined with brisk acceleration – at a price that's much more affordable than the six-cylinder model.

Not saying a hundred grand is within easy reach of any old buyer, but if you have that dosh just lying around, the 428i would be the one to buy.

BMW 420d pricing and specifications:
Price: $88,800 (plus on-road costs)
Engine: 2.0-litre four-cylinder turbo-diesel
Output: 135kW/380Nm
Transmission: Eight-speed automatic (six-speed manual optional)
Fuel: 4.8L/100km (ADR Combined)
CO2: 127g/km (ADR Combined)
Safety Rating: TBA

BMW 428i pricing and specifications:
Price: $97,500 (plus on-road costs)
Engine: 2.0-litre four-cylinder turbo-petrol
Output: 180kW/350Nm
Transmission: Eight-speed automatic (six-speed manual optional)
Fuel: 6.7L/100km (ADR Combined)
CO2: 157g/km (ADR Combined)
Safety Rating: TBA