BMW 4 Series Convertible Review

$88,800 $126,600 Mrlp
  • Fuel Economy
    6.7L
  • Engine Power
    180kW
  • CO2 Emissions
    156g
  • ANCAP Rating
    N/A

The first ever 4 Series Convertible is bigger than before, but is that necessarily better?

The first ever BMW 4 Series Convertible has arrived on sale in Australia to replace the 3 Series drop-top, and it’s bigger, more mature, more powerful and more efficient than its predecessor. But it’s also considerably more expensive.

The 4 Series Convertible range kicks off with the base model diesel-powered 420d at $88,800, with the mid-level petrol 428i priced at $97,500 and the flagship 435i well above it at $126,600 – by comparison, the 3 Series Convertible was priced from $77,900 for the 320d, $82,545 for the 325i and $112,545 for the 335i.

The new model is much larger than before: it has an extra 50mm between the front and rear wheels for improved space and ride refinement, and feels more planted as its track has been widened by 45mm at the front and 81mm at the rear.

It now measures 4638mm from tip to toe, and 1825mm across, making it longer than the Audi A5 Cabriolet (priced from $79,790) but not quite as large as the Infiniti Q60 Convertible (formerly G37, from $77,900), Lexus IS250C (from $76,600) or Mercedes-Benz E-Class Cabriolet (from $88,900).

BMW says there is more standard gear than before, and a quick glimpse at the base model’s specification proves that point: every 4 Series Convertible has a reverse-view camera, front and rear parking sensors, bi-xenon headlights, auto wipers and lights, an auto-dimming rear-view mirror, dual-zone climate control, heated seats, leather trim, satellite navigation, Bluetooth phone and audio streaming, USB input and BMW’s iDrive control system with touch pad. Read full pricing and specifications details for the new BMW 4 Series Convertible here.

Each of the 420d and 428i models can be optioned with a styling pack free of charge, each with 18-inch alloys for the former or 19s for the latter. The Sport line has gloss black interior and exterior highlights, a sports steering wheel and the choice of black leather with red stitching or full-red leather trim; the Luxury line has chrome exterior trimming and beige, brown or black leather; and the Modern line includes satin aluminium exterior trimming and “oyster” interior trim.

We spent time in each of the models in the range.

The entry-level 420d is powered by a 2.0-litre turbo diesel four-cylinder producing 135kw of power at 4000rpm and 380Nm of torque between 1750rpm and 2750rpm, which is mated to an eight-speed automatic gearbox (or six-speed manual at no cost, as is offered for all 4 Series models). It has a claimed consumption figure of just 4.8 litres per 100 kilometres and a claimed 0-100km/h sprint time of 8.2 seconds. During our time in the car we saw 6.2L/100km.

Its diesel powertrain means it will likely be a niche model – not that there’s anything notably wrong with it. It’s refined, smooth revving and even sounds quite nice when you give it a boot-full.

There is some minor turbo lag from a standstill and that typical diesel clatter, albeit well restrained, at low idle and low speeds. Once its up and running it proves a tractable engine.

In the middle is the 428i, which in Coupe guise is the pick of the bunch. With a brilliant turbocharged four-cylinder engine under the bonnet producing 180kW at 5000-6500rpm and 350Nm from 1250-4800rpm, it’s extremely useable and mighty peppy. Performance is claimed at 6.4sec for the 0-100km/h dash, while fuel use is rated at 6.7L/100km. We saw 8.0L/100km for our test.

It revs cleanly and smoothly, gathering pace quickly and delivering power with silky response. It proved itself quite amenable at all speeds, sauntering nicely in urban running while also sitting comfortably at highway speeds, and also offering plenty of reward to the right foot if the opportunity arose.

The range-topping 435i’s 3.0-litre six-cylinder turbocharged mill is the go-fast option. With 225kW at 5800-6400rpm and 400Nm from 1200-5000rpm it’s a lively thing, offering rapid acceleration: its claimed 0-100km/h time is 5.5sec, while fuel use is 7.7L/100km (we saw 9.1L/100km on our test).

This engine is strong in every application – it offers excellent low-rev pulling power and a charming exhaust note as you lift off the accelerator – though it could be a little louder. It also proves a good tool for tootling around the suburbs, too.

All cars tested were fitted with an eight-speed automatic transmission with steering wheel paddleshifters. In each car and in all instances the gearbox worked smoothly and cleverly, with precise shifts and no hesitation under pressure. The ‘box will, however, overrule the driver unless the car is in Sport+ mode – Sport mode will still change up a gear even when manual shifting is selected.

When it comes to the drive experience of each car, all offered suspension that proved comfortable and well sorted, dealing with bumpy country roads and pockmarked city streets admirably. This was the case in the 420d, which was the only car available that was not fitted with adaptive suspension, and the 428i and 435i which both come with the adjustable damper system as standard.

All felt taut with the roof up or down, too, with BMW making a big deal of the fact the new model is 40 per cent stiffer than the 3 Series Convertible thanks to cross-bracing under the body and a new inverted U-shaped rollover bar behind the rear seats. There was little in the way of scuttle shake, and only a slight hint of wobble through the steering wheel in some situations. The noise insulation is brilliant with the roof up, while with it down the cabin never felt uncomfortably blustery.

However, there’s a problem with the 4 Series Convertible that could rule it out for some sporty convertible aficionados – it’s heavy. Very heavy.

The folding metal roof and all of the intricate mechanical equipment that helps it go up and down in 20 seconds (up to 18km/h) adds a whopping 225 kilograms over the equivalent Coupe variants. That means the range-topping 435i weighs a bloated 1700kg, while the two more affordable models weigh 1640kg.

That extra weight is clearly noticeable in the 435i when you push it. Through a tight, twisting section of road we found it straining against driver commands, pushing straight on at speed while its tyres squealed at minimal provocation as the car’s weight shifted from side to side.

The 420d and 428i proved more nimble, and their 60kg lighter kerb weight is clearly noticeable through corners. Still, none felt agile or exceptionally light-footed through the bends unlike the loveable and chuckable 428i coup. And while that may be fine for the majority of buyers who are after a four-seat convertible more as a cruiser than a racer, we were left wishing that BMW had opted for a lighter fabric roof (for those who are curious, the move to go with a hard-top was driven by the US, where BMW will sell the bulk of its 4 Series Convertible models).

It gains points back for its interior, which is comfortable enough to fit four adults and finished to a high standard, as BMW buyers would expect. It would prove a great weekend getaway car provided you’re happy to pack light or keep the roof up – the boot is just 220 litres with the roof down, or 380L with it up.

Fat jokes aside, the 4 Series Convertible is still an impressive piece of machinery - well equipped, reasonably priced and comfortable with the roof up or down. And, just like in the coupe, the 428i was the model we'd choose.