BMW 4 Series Convertible review

Is the BMW 4 Series Convertible a good car?

While the open-top BMW 4 Series Convertible can’t quite match its Coupé sibling’s driving dynamics, it’s still a deeply appealing prospect that’s more involving than pretty much any other four-seat convertible at this price – although there aren’t many rivals to choose from. Few other cabriolets deliver such a strong mix of performance, handling and long-distance comfort – and in the BMW’s case, it’s combined with impressive tech, too.

How much does the BMW 4 Series Convertible cost?

As its name suggests, the BMW 4 Series range sits just above the 3 Series saloons and Touring estate cars in the brand’s line-up. With focus on style, the 4 Series is available in two- and five-door coupe guises, as well as the four-seater Convertible tested here. The original version was launched in 2013 as a replacement for the 3 Series Convertible, which can trace its roots back to the E21 series car that was launched in 1978. The current second-generation 4 Series Convertible was launched in 2021, while a facelifted version landed in UK showrooms in 2024. 

It wasn’t just the 4 Series Convertible’s styling that went under the knife as part of the refresh, because BMW also heavily trimmed the model line-up. Buyers can now choose from two versions, starting with the entry-level 420i. Weighing in at just over £51,000, it features a 2.0-litre four-cylinder petrol engine that drives the rear wheels through an eight-speed automatic gearbox. It’s only available in M Sport guise, but that does mean a generous kit count that includes LED headlamps, three-zone climate control and a reversing camera.

As with the Coupe and Gran Coupe models, the flagship of the range is the M440i xDrive, which packs a powerful 369bhp turbocharged 3.0-litre straight-six petrol motor, four-wheel drive and an eight-speed automatic. It costs around £68,000 and is just as well equipped as the 420i, but it benefits from some head-turning visual tweaks that highlight range-topping status. These include larger 20-inch alloys, gloss black trim inserts, unique door mirrors and larger twin-exit exhaust pipes.

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Under the bonnet, the 4 Series Convertible has the same limited all-petrol engine line-up as the Coupe and Gran Coupe versions. Entry-level level models get a turbocharged 2.0-litre four-cylinder that gets an 11bhp mild-hybrid boost for a total of 181bhp.

Next up is the M440i xDrive, which packs a muscular turbocharged 3.0-litre straight-six engine that makes 369bhp and a thumping 500Nm. Like the 420i, it uses mild-hybrid tech to boost fuel efficiency, but as the xDrive badge suggests, there’s also four-wheel drive as standard. If you want to go even faster, there’s a 503bhp BMW M4 Convertible, offering an even quicker way of messing up your hair.

The open-top conversion of the 4 Series Coupe requires some extra body strengthening, which means the Convertible is around 150kg heavier than its tin-top sibling.  As a result, performance is a little blunted compared to the Coupe, with the 420i completing the 0-62mph sprint 0.3 seconds slower at 8.2 seconds. On the plus side, the four-cylinder engine is smooth and feels responsive, its standard eight-speed automatic gearbox serving up slick and swift gearchanges.

The M440i suffers from a similar weight penalty, meaning it takes 0.4 seconds longer than the Coupe to go from 0-62mph. Yet with a time of 4.9 seconds, it’s no slouch. It’s a fantastic engine, too: strong, smooth and more tuneful than ever. Better still, with the roof lowered you can get even closer to the straight-six engine’s trademark snarling soundtrack.  

Not only does the extra mass have an effect on performance, it can be felt through a series of corners too. Compared with the lighter 4 Series Coupe, the Convertible doesn’t have the same delicate balance. There’s still great turn-in and solid body contro, and it’s still better to drive than the more ponderous but plush-riding Mercedes CLE Cabriolet.

As with the coupe version, the M440i gets an upgraded chassis to match. Upgrades include unique settings for the stroke-dependent dampers and an active differential on the rear axle to boost agility. There’s also the xDrive all-wheel drive that delivers confidence-inspiring traction on slippery surfaces. That said, the BMW’s steering still lacks the feedback you’d expect from a high-performance car, although it does respond quickly and accurately to your inputs. 

Either way, the 4 Series Convertible remains a great long-distance cruiser. A controlled high-speed ride combines with great stability, and that torquey engine to make for a very relaxing companion. The fabric roof does a great job of isolating road and wind noise, and with the roof down, buffeting in the front is minimal – especially with the wind deflector up.

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Wind-in-the-hair thrills don’t necessarily have to mean big bills, certainly when it comes to running costs. Thanks to the addition of mild-hybrid tech and BMW’s Efficient Dynamics features that run to active aerodynamics, regenerative braking and low friction engine internals, the 420i and M440i are surprisingly easy on fuel.

With its smaller, lower-powered engine, it’s the entry-level 420i, which is the more fuel-efficient model. Its 2.0-litre motor promises as much as 41.5mpg on the WLTP cycle, and we found that this BMW can be even more efficient in real-world use if you’re gentle, with figures in the mid-40s being possible. CO2 emissions of as little as 154g/km are further evidence of the 420i’s strong efficiency.

Given its obvious performance potential, the M440i’s claim of 34.4mpg is not bad at all – and not far behind the 36.2mppg of the lighter Coupe. That said, start to extend that glorious straight-six engine for extended periods, and you’ll see that figure slump into the teens. Either way, its CO2 emissions figure of 184g/km is impressive for a 369bhp rag top with a 155mph top speed. 

Both versions of the 4 Series Convertible are priced at more than £40,000, meaning private buyers will face a £415 surcharge on their annual Vehicle Excise Duty (VED) bill for the first five years following the car’s initial registration.

Company car drivers paying benefit-in-kind (BiK) tax will be hit even harder. The 420i attracts a Benefit-in-Kind rate of 35 per cent, while the M440i is higher still at 37 per cent. Unfortunately, there are few, if any, electric or plug-in convertible cars on the market, so business users will simply have to suck it up if they want to enter the corporate car park with the top down. 

Insurance groups for the 4 Series Convertible models reflect those of the Coupe, ranging from 29 for the 420i M Sport to group 40 for the M440i xDrive.

Despite the lure of the BMW badge, the 4 Series Convertible shed value at a greater rate than the Mercedes CLE Cabriolet. The 4 Series Convertible holds on to between 36 to 41 per cent after three years or 36,000 miles, according to our expert data, with the 420i maintaining the most value in the range. In comparison, the CLE Cabriolet will hang on to 39 to 49 per cent over the same period.

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BMW has bolstered its open-top range with the 4 Series Convertible, which joins the larger BMW 8 Series in offering fresh air thrills. Essentially a 4 Series Coupe with the roof removed, the Convertible is based on BMW’s CLAR (short for Cluster Architecture) LK platform. Adapted for the current, eighth-generation 3 Series saloon (codenamed G20, it also underpins the BMW 3 Series Touring Estate (G21), the 4 Series Coupe (G22) and the BMW 4 Series Gran Coupe (G26). 

Like those cars, the 4 Series Convertible received a mid-life refresh in 2024, although it didn’t do much to soften the car’s aggressive looks. The brand’s trademark double-kidney front grille remains as imposing as ever, while with the roof down, the BMW’s slab sides become even more accentuated. Still, there’s no denying the 4 Series attracts attention, while the revised LED front and rear light signatures add an eye-catching flourish at night.

When the current 4 Series Convertible launched in 2021, one of the biggest changes was adoption of a traditional fabric roof in place of the previous model’s folding hard-top. BMW argued that the complexity and packaging issues that came with that old roof were no longer worth it when a properly engineered and insulated canvas top can offer similar refinement, even at speed.

The switch is a logical one because it brings plenty of benefits. For a start, the soft top is 40 per cent lighter, and perhaps more importantly, it’s easier to fold away. The process takes 18 seconds and can be done on the move at up to 31mph, ensuring you can make the most of any breaks in the weather.

Inside, the Convertible’s layout is largely identical to that of the 4 Series Coupe, complete with the same flawless build quality. You also get the dashboard design complete with BMW’s ‘Curved Display’. This looks like a single ‘floating’ screen, but is actually made up of two parts: a 12.3-inch driver’s instrument panel and 14.9 inch touchscreen in a wide-screen format, running the latest OS 8.5 software.

Like many rivals, the latest set-up features a voice-controlled concierge-style ‘Intelligent Personal Assistant’ that allows you to communicate using Apple’s Siri or Amazon’s Alexa. You can adjust the temperature, change the audio settings or program the sat-nav without taking your eyes off the road. This is especially useful for the climate controls because the physical controls of the pre-facelift model have been removed, meaning you need to resort to a touchscreen menu if you want to alter any settings by hand. The firm’s trademark iDrive controller remains, which is intuitive and easy to operate on the move.

Sat-nav, stereo and infotainment

Like the rest of the 4 Series line-up, the Convertible’s recent facelift extends to the interior. That means it gets the same slick-looking curved digital dashboard layout as the 3 Series saloon, comprising a 12.3-inch digital driver’s display, and a large 14.9-inch central touchscreen that features the brand’s latest iDrive set-up. It also boasts the brand’s most recent 8.5 operating systems, which is faster and more responsive.

A DAB radio comes as standard, along with three years of free satellite navigation and connected services, the latter giving you access to BMW Apps informing you about live weather and traffic reports. Apple CarPlay and Android Auto smartphone connectivity are also standard across the range, while the car's Emergency Call system will automatically contact the emergency services in the event of a collision.

The stereo, along with many other functions, can be accessed by using the central control display as a touchscreen, as well as via voice commands, or by using the iDrive controller. 

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You don’t normally buy a convertible model for its practicality, but the good news for BMW 4 Series buyers is that the drop top version is surprisingly versatile. In fact, if you want to carry more than the driver and a passenger, then the German machine is one of the few options at the more affordable end of the market.

Given it’s essentially an open-top 4 Series Coupe, it’s no surprise to find that the Convertible feels similarly spacious inside, for those sitting up front at least. There’s plenty of space, while, like all BMWs, the driver is able to set their seat very low for a sporty driving position. The seats are comfortable and supportive, plus they feature multi-way adjustment. They also feature heated bases and backs, as well as heating ducts set in the headrests that blow warm air onto the necks of the occupants – perfect for driving al-fresco on chilly days.

The news is a little less good for those sitting in the back, however. To accommodate its folding roof mechanism, the BMW’s designers have needed to create a smaller rear seating area. That means there’s only space for two adults (there’s no third seatbelt in the middle), while the more upright backrest and narrower cabin mean it's not as comfortable as the Coupe. What’s more, with its smaller rear windows, the 4 Series Convertible can feel claustrophobic with the roof up.

There’s decent storage space for odds and ends, with a large glovebox and well-shaped doorbins in the front. The centre console between the front seats houses a handy tray (and optional wireless charging pad) for smartphones and a cup-holder, while the large armrest opens to reveal a deep compartment complete with USB and power sockets. In the back, occupants have to make do with a couple of small compartments on each side of the bench.

There are more compromises when it comes to boot capacity, although it’s still a relatively spacious choice for a drop top. With the roof in place, there’s a handy 385 litres of space, which is 85 litres less than the Coupe, but the same capacity as the Mercedes CLE Cabriolet. You can fold down the seat back to extend the boot, but it’s more useful as a place to store the folding wind deflector.

If you want to combine some summer fun with a caravan holiday then the 4 Series Convertible will happily oblige. Like the Coupe, the 420i features a maximum braked towing weight of 1,600kg, while the more powerful M440i increases this figure to 1,800kg. 

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In 2019, Euro NCAP subjected a pre-facelift version of the 4 Series Coupe to its extensive safety assessments. Although slightly less stringent than the safety organisation’s current procedure, the results highlighted this BMW’s strong protection for adult and child occupants and its excellent advanced driver aids.

These additional safety systems come under what BMW terms Active Guard Plus. This includes speed-limit information to warn you about the restrictions on the road you’re driving on, a lane-departure warning to let you know if you are straying out of your lane, a collision and pedestrian-warning system with a city brake function to put the brakes on if it thinks you’re going to hit something to either avoid or mitigate a collision, and cruise control with a speed-limiter function. 

What’s more, the 4 Series Convertible has extra features designed to protect occupants in the unlikely event of a rollover. Not only are the A-pillars and windscreen surround strengthened to support the weight on the overturned car, but there are pop-up roll bars hidden behind the rear seats that can be deployed in milliseconds to help keep occupants in the back safe.

The relative rarity of the BMW 4 Series Convertible means it didn’t appear in our 2024 Driver Power satisfaction survey. However, the very closely related 3 Series saloon finished an impressive 18th out of 50 cars in the same poll, with owners praising the car’s quality, tech and driving experience. BMW also performed well in the manufacturer’s rankings, placing 14th out of 32 manufacturers – seven places higher than in 2023.

BMW offers its standard three-year unlimited-mileage warranty on the 4 Series Convertible, including a three-year subscription to the BMW Emergency breakdown service. This is broadly similar to the warranty offered by Mercedes, but better than the 60,000-mile limit imposed by Audi. The BMW warranty can be extended after the initial three-year period with either monthly or annual payments and differing levels of cover.

As with all BMW models, the 4 Series Convertible features a time and use-based service schedule, with the car’s onboard computers determining when to visit a workshop. You can purchase a BMW Service Inclusive plan with your new car, either paying upfront to cover you for the first five years or 62,000 miles, or opting for a BMW Pay Monthly Service Plan over three years, with prices starting from around £30 per month.

BMW 4 Series Convertible alternatives

The market for four-seat soft-tops has shrunk considerably over the last few years, with only a handful of models left. At one end of the spectrum are upmarket superminis such as the MINI and Fiat 500e (although the latter essentially features a large fabric sunroof), while at the other are fast and expensive models like the Bentley Continental GTC, Maserati Gran Cabrio and Porsche 911 Cabriolet.

Even BMW has limited its open air offerings, with the 4 Series Convertible now the entry-point in the range, sitting below the 8 Series Convertible. There’s no longer a more compact 2 Series Convertible.

In terms of direct rivals, the 4 Series Convertible only really has one – the Mercedes CLE Cabriolet. The German machine features more elegant exterior lines and a wider range of engines, including petrol and diesel options. It also matches the BMW’s interior for space and upmarket appeal. However, with its softer ride and less engaging handling, it’s more of a comfortable cruiser than the poised and precise BMW.