New BMW 4 Series Convertible drops disguise ahead of unveiling

The launch of the BMW 4 Series coupé is soon to followed up with a convertible version – and the latest spy shots show the model with barely any disguise. 

Seen in a compound at one of the Munich brand's development facilities alongside other disguised mules, the drop-top is, as expected, close to the hard-top in terms of its body design. It'll be the smallest four-seat convertible model BMW makes because the next-generation 2 Series will come in coupé and four-door forms only. 

With the current BMW 2 Series and new 8 Series Convertible adopting a cloth roof, it’s not a huge surprise that BMW has elected to ditch the folding metal roof for the second generation of the 4 Series. The decision also brings the car in line with its closest rivals: the Audi A5 and Mercedes C-Class cabriolets.

Doing so reduces the complexity of engineering and producing an intricate folding hard-top system and is likely to improve the long-term reliability that complicated folding hard-tops are often criticised for lacking. 

The move will also reduce the car’s kerb weight, aiding handling, performance and fuel efficiency. Expect the new convertible to be less than 100kg heavier than the coupé. With less mass to store underneath the bootlid when the roof is down, improvements in rear seat and luggage room are possible, too.

The new 4 Series revealed a bold and controversial front-end styling direction for BMW last month. It also introduced a new aluminium-intensive platform, a wider and longer body with a wheelbase matching that of the 3 Series saloon, and the latest array of technology. 

It will go on sale with three petrol engines and one diesel. Two 2.0-litre four-cylinder petrols offer 181bhp (420i) and 254bhp (430i), while a 48V mild-hybrid 2.0-litre four-cylinder turbo diesel delivers 187bhp (420d) and official fuel economy of between 67.3mpg and 72.4mpg.

The range-topper will be the M440i xDrive, producing 369bhp and 369lb ft from a 48V mild-hybrid 3.0-litre six-cylinder turbo petrol engine. It’s claimed to be capable of 0-62mph in 4.5sec, a top speed of 155mph and fuel economy of 39.8mpg to 41.5mpg. Mild-hybrid six-cylinder diesels producing 282bhp (430d) and 335bhp (M440d) are due next March.