BMW 4 Series Convertible (2014-2020) Review

Undoubtedly, the defining feature of the BMW 4 Series Convertible is its folding metal roof. Compared to cars with a fabric soft-top, the 4 Series scores points for improved security and better levels of noise insulation. 

Yet the BMW 4 Series Convertible is more than just a fancy roof. It looks stylish, rides and handles with self-assurance, plus has the benefit of a premium German badge on the bonnet. 

It should appeal to those who like the idea of an open-top car, but want to use it all year round. In addition, those who have to park on the street will appreciate the improved security of the metal top. Only space in the boot, and a lack of legroom for rear passengers, could prevent it being a winner for most. 

The BMW 4 Series Convertible range attempts to cover most bases, from buyers who want ultimate luxury to those in need of something sportier. With the wide array of engine and trim combinations, there should be a version to suit you.

The 435d diesel engine impresses if you are doing big miles. It comes with xDrive four-wheel drive as standard, and delivers a mighty 313PS. That’s good enough for 0-62mph in around five seconds, yet can also achieve up to 44mpg. 

If a petrol suits your needs better, the 428i four-cylinder (later replaced by the 430i) offers a good blend of power and frugality. Whatever the engine, we would plump for the eight-speed sport automatic gearbox over the manual.

M Sport trim offers decent value for money, along with sportier styling. Even the standard sports suspension does not upset ride quality hugely. 

With the demise of cars like the Volvo C70 and Volkswagen Eos, four-seater cabriolets with a folding metal roof are in short supply. Unless your budget stretches to a Ferrari Portofino, the BMW 4 Series Convertible really is your only option.

The Audi A5 Cabriolet and Mercedes-Benz C-Class Cabriolet are closer rivals. Both offer premium badges and classy styling, but also make do with fabric roofs. Space in the back of the Audi and Mercedes is also limited, just like the 4 Series.

Choosing between the three is tricky, with the BMW offering the best driving experience. However, the Mercedes C-Class is more comfortable, while the Audi A5 has the nicest interior design.

It may not be the most exciting interior design, but there should be no concerns about how well put together the BMW 4 Series Convertible is.

The trim feels made to last, and you will need to search hard to find anything that feels like it was built down to a cost. 

All of the usual touchpoints are made from expensive-feeling materials. The steering wheel in M Sport cars is especially nice to hold, and comes complete with multi-function buttons. A heated steering wheel appears on the options list, and could be handy for going topless on chillier days. 

Regardless of the level of trim chosen, Dakota leather upholstery is fitted to all BMW 4 Series Convertibles. Fancier versions have a greater choice of leather colours, but all make it feel luxurious on the inside.

The various trim levels present a myriad number of interior finishes for the dashboard and centre console. These range from satin silver on entry-level SE cars to anthracite wood and gloss back on Luxury and Sport models. Range-topping M Sport versions use a hexagonal aluminium finish.

BMW’s iDrive system is now almost two decades old, and the company has refined and updated it considerably since it was first introduced. It should become easy to use with familiarity.

Lower trim levels come with a 6.5-inch screen atop the dashboard, whereas M Sport models feature a bigger 10-inch display. This can also be added to other cars as part of the optional BMW Professional package, and is something worth looking out for on used models.

Satellite navigation comes as part of the BMW Business media package, which is standard on Luxury and M Sport models. 

All cars come with a DAB radio, along with Bluetooth mobile phone connectivity and USB ports. BMW still charges extra to add Apple CarPlay to its cars, however, and the BMW 4 Series Convertible was no different. It can only be found on later models with the Professional or Professional Plus media packages. 

This is all operated by the iDrive rotary controller, mounted on the centre console. There are also controls mounted on the steering wheel, while voice commands are included with certain packages. 

Like the competing Audi A5 and Mercedes-Benz C-Class, BMW describes the 4 Series as being a four-seater convertible. The reality is slightly different, though.

Those in the front of the BMW are unlikely to have any complaints about the space on offer. With a wide range of adjustment from standard electrically adjustable front seats, there should be no issues with getting comfortable. Headroom is great with the roof in place, and obviously becomes unlimited with it retracted. 

Unlike its competitors, a sliding armrest is not standard across the range. It’s a strange omission given the minimal cost of adding it to the car.

In the rear, passengers are less likely to be content with their lot. Legroom is particularly limited for those beyond child size, meaning the 4 Series functions as a four-seater in name only. Head and shoulder room are at least acceptable in the back, while child seats will also fit without an issue. Should you install the optional wind deflector, however, the rear seats will become completely unusable. 

Having a hard-top roof, made from glass and metal panels that fold elegantly together, certainly makes for an impressive sight. However, storing it needs plenty of space, as it cannot be safely squashed down like a fabric top. 

To keep a clean look for the rear decklid, all these components disappear into space usually reserved for the boot. It means the standard 370-litre boot capacity drops to just 225 litres with the top down. That is the difference between having a boot on par with a family hatchback, then compressing it to one found in a city car. 

It means you will need to pack sparingly, should you want to use the BMW 4 Series Convertible for weekends away and still drop the roof. Given the limited space in the back seats, using them to store luggage is another option. A ski hatch is standard to help load longer items, although folding rear seats are relegated to the options list.

The BMW 4 Series Convertible dimensions are 4638mm long, 2017mm wide and 1384mm tall.

BMW launched the BMW 4 Series Convertible in 2014 with a limited selection of engines, but expanded the options over time.

Petrol choices start with the 420i 2.0-litre four-cylinder turbo, producing 184PS and capable of 0-62mph in 8.2 seconds. It will be sufficient for most drivers, but those in need of outright pace need to look elsewhere. 

Salvation may come with the 428i, another turbocharged 2.0-litre four-cylinder engine producing 245PS. BMW later replaced this with the 430i in 2016, taking power to 252PS. It can reach 62mph in 6.3 seconds, and feels much more lively. 

Top dog in the petrol range is the 3.0-litre turbocharged straight-six. Originally badged 435i, it offers an impressive 306PS. In 2016, it was boosted further to 321PS in the 440i, with the 0-62mph time falling to 5.4 seconds. Expect big running costs, though.

Diesel engines kick off with the 420d, which offers 190PS after 2016 and acceleration from 0-62mph in 8.1 seconds, the extra torque making it feel quicker than the 420i. 

A 224PS 425d four-cylinder diesel was added in 2016, then rebranded as the 430d in 2017 with 258PS. It offers more acceleration, but might be overlooked in favour of the impressive 435d. 

With 313PS from its twin-turbocharged straight-six, the 435d rockets from 0-62mph in 5.2 seconds. Standard xDrive four-wheel drive helps control the power, with the biggest diesel still able to offer up to 44mpg.

Originally, a six-speed manual gearbox was standard for most models, although this was later phased out, making the eight-speed automatic the only choice. The 430d, 435d and 440i can only be had with the automatic.

The issue of refinement is where the extra weight and complexity of the folding metal roof begin to pay dividends.

While many modern cabriolets with fabric soft-top roofs are quiet, they cannot come close to a tin-top rival. The metal roof of the BMW 4 Series Convertible makes it just as refined as the regular Coupe when raised, shutting out noise from the road.

BMW worked hard to make the 4 Series as aerodynamic as possible, which also helps improve overall refinement. Wind noise is minimal with the roof up, yet still well controlled with it lowered. Go top-down and you should still be able to hold a conversation at motorway speeds. 

Those in the front will notice only minimal levels of buffeting with the roof down, although rear seat passengers will be more aware of draughts. Fitting the optional wind deflector will make front occupants even more comfortable, but also makes the back seats completely unusable. 

An important optional feature on the BMW 4 Series Convertible is the Air Collar system. This uses heater vents built into the seats to blow warm air across the neck of the driver and front-seat passenger. It works remarkably well, making it possible to use the 4 Series with the roof down even when it is chilly outside. 

The Air Collar comes as part of the Convertible Comfort package. This includes the previously mentioned rear wind deflector, plus a heated steering wheel to further the BMW’s winter credentials.

One thing to remember with the folding roof is that it takes 20 seconds to raise or lower. Also, unlike its rivals, it can only be done at speeds of up to 8mph. This means you will have to pull over quickly should you get caught in a sudden rainstorm with the top down. 

Although the BMW 4 Series Convertible has not been formally tested by Euro NCAP, the related 3 Series scored the maximum five stars when evaluated. We imagine the 4 Series would perform just as well should the worst happen.

A host of airbags are standard in the BMW 4 Series Convertible, along with rollover protection. This detects if the car is about to flip, and deploys pop-up roll bars to keep the occupants safe. Stability control and traction control are also fitted as standard. 

Parking sensors for both the front and rear are fitted to all models, helping slot into the tightest spaces. A reversing camera could be optioned as part of the Advanced Parking pack, which also includes Park Assist. Later cars also had the option of a full surround-view camera. 

An optional Driving Assistance Package brings more safety technology to the party. This includes Forward Collision Warning and Lane Departure Warning. Xenon headlights were fitted to all BMW 4 Series Convertibles from launch, complete with headlight washers. An update in 2016 would see these replaced with full LED headlights instead, along with LED fog lights for all cars. 

The two rear seats come fitted with ISOFIX attachment points, allowing child seats to be fitted safely and securely. BMW uses run-flat tyres across the BMW 4 Series Convertible range, meaning there is no spare wheel included.

The BMW 4 Series (including the Convertible and Coupe variants) achieved a strong 9.43 out of 10 for reliability in the HonestJohn.co.uk Satisfaction Survey, making it one of the better-performing BMWs. As with any convertible car it's worth ensuring that the roof is operating correctly and has been regularly used - keeping it closed all the time causes more problems than exercising the folding mechanism once in a while.

As a brand BMW finished a relatively disappointing 20th overall out of 30 manufacturers, although its overall reliability score was also good.

Being a desirable car with a premium badge and strong performance, insurance costs are always going to be at the higher end of the scale. Naturally, the BMW 4 Series Convertible is a car aimed at more experienced drivers. 

The 420i in SE or Sport trim should be the cheapest to insure, rated at group 30 out of 50. M Sport trim pushes this to group 31 with the same engine. At the other end of the petrol scale, the 440i M Sport is (a relatively reasonable) group 40.

In terms of diesels, the 420d was originally rated as group 31, although this was revised upwards following the 2017 facelift. This change pushed the 420d M Sport to group 34.

Having been introduced in 2014, the BMW 4 Series Convertible straddles different VED (road tax) regimes. It means two identical cars registered just days apart could have radically different costs, so be sure to check carefully.

Earlier examples of the 420d SE fall inside the bracket of £30 per year. This is limited to models with 17-inch alloy wheels and the optional automatic gearbox, which produce 116g/km of CO2. It means these cars have the cheapest VED across the range. 

Be aware that many later models had a list price above £40,000. This means they incur an additional £355 surcharge on top of the £165 annual VED rate. The is due for five years after the first year of registration. Benefit-in-kind company car tax rates range from 33% for the 420i SE through to 37% for the 440i M Sport. 

BMW changed the trim levels during the lifespan of the 4 Series Convertible, meaning not all were available consistently. BMW 4 Series Convertible SE models have 17-inch alloy wheels, dual-zone climate control, a DAB radio, leather seats, and exterior trim in matt aluminium. BMW 4 Series Convertible Sport adds 18-inch alloy wheels, gloss black trim for the front and rear bumper inserts, sports seats and a Drive Performance Control switch. 

BMW 4 Series Convertible Modern specification was only available until May 2014, but featured 18-inch wheels, matt chrome exterior trim and ambient interior lighting. The BMW 4 Series Convertible Luxury trim level existed until July 2017, with 18-inch wheels, chromeline exterior trim, satellite navigation and anthracite wood interior trim.

Finally, BMW 4 Series Convertible M Sport models bring 18-inch alloy wheels, bespoke M body styling, an M Sport steering wheel, sports seats, M Sport suspension and black headlining. The M Sport trim level represents good value for money – and gives the 4 Series more presence on the road.