The roof automatically opens and closes in 20 seconds at the push of a switch on the centre console, at speeds of up to 30mph. The roof’s folding mechanism has been carried over from the 1 Series, but a four-layer fabric top is new and features additional insulation and greater acoustic comfort. This has resulted in a reduction of interior noise by five decibels for front seat passengers and 7 decibels in the rear.
The 2 Series convertible weighs about 150kg more than the equivalent coupé model due to the roof mechanism and the extra chassis reinforcement in the side panels. Torsional rigidity of the body is said to be approximately 20 per cent stiffer than the 1 Series convertible.
Four engine variants will be offered, all of which are more powerful yet on average 18 per cent more frugal than the units offered in the 1 Series convertible.
The £37,710 BMW M235i convertible is the halo model in the range. Powered by a 2979cc inline six-cylinder TwinPower turbo engine, the car produces 322bhp at 5800-6000rpm and 332lb ft between 1300-4500rpm.
When equipped with the standard six-speed manual gearbox, the M235i convertible can sprint from a standstill to 62mph in 5.2sec – just 0.2sec slower than the Coupe – and hit a top speed of 155mph.
By comparison, the M235i coupé is capable of 0-62mph in 5sec. Fuel economy on the combined cycle is a claimed 33.2mpg and CO2 emissions are put at 199g/km.
Two other petrol variants are offered, both using the 1997cc inline TwinPower turbo four-pot in differing states of tune.
The £29,180 220i convertible produces 181bhp at 5000-6250rpm and 199lb ft at 1250-4000rpm. It can cover 0-62mph in 7.5sec and has a top speed of 143mph. This variant offers claimed fuel economy of 43.4mpg on the combined cycle and CO2 emissions of 151g/km.
The 228i convertible, which costs £31,550, has 242bhp at 5000-6500rpm and 258lb ft at 1250-4800rpm. Its 0-62mph time is 6.1sec and its top speed is 155mph. BMW’s figures put fuel economy at 41.5mpg combined and CO2 emissions at 159g/km.
The sole oilburner in the range is the 220d, which is powered by a new four-cylinder turbodiesel that has also been installed in the BMW 2-series Active Tourer and latest Mini. The 1995cc unit develops maximum power of 187bhp at 4000rpm and 295lb ft at 1750-2500rpm. This particular version costs £29,965.
When this engine is mated to the six-speed manual gearbox and the car is equipped with standard-fit 16-inch wheels and tyres, BMW claims a combined fuel economy of 64.2mpg and CO2 emissions of 116g/km; the optional eight-speed automatic improves that figure to 68.8mpg and 108g/km.
The standard-fit gearbox is a six-speed manual, while an eight-speed automatic with Steptronic is offered as an option. Equipped with a coasting function, the transmission provides better fuel economy across the range than the manual.
Also available is a Steptronic sport transmission that offers even quicker gearshifts, a launch control function and steering-wheel-mounted paddle shifters. Expect to pay a premium of around £1500 for the Steptronic, or £1650 for the Steptronic sport.
BMW’s switchable driver mode system, Driving Experience Control, is standard on all variants. The 218i, 220i and 220d offers three driving modes – Comfort, Sport and fuel-efficient Eco Pro – whereas the M235i adds Sport+.