BMW 4 Series Convertible review

We love a bit of innovation, but sometimes traditional methods are best – as demonstrated by the BMW 4 Series Convertible.

You see, after switching to a folding metal roof for the previous-generation car, this convertible variant of the BMW 4 Series has now returned to a good old-fashioned fabric one.

Why? Well, a soft-top takes up far less space. You could fit your luggage or the roof in the boot of the previous-generation car, but not both at the same time. The revised design fixes that. The 4 Series Convertible has also gained mild-hybrid engine tech, potentially improving efficiency and performance.

There are not really any direct rivals to this model at the moment, but if you're after some wind-in-your-hair motoring, you might also be considering the BMW Z4, the Mercedes CLE Cabriolet, the Porsche 718 Boxster or even the VW T-Roc Cabriolet.

So how does the BMW 4 Series Convertible score against the best cabriolets for performance, interior quality, practicality and costs? Read on to find out…

The BMW 4 Series Convertible range kicks off with the 420i model, which uses a 2.0-litre turbocharged petrol engine producing 181bhp. It’s our pick in the BMW 4 Series Coupé and remains so here, because it should be brisk enough for most people and makes sense financially.

The convertible variant has to lug around 165kg more than the coupé, so the engine does have a harder time of it here. It takes a not-particularly-sporty 8.2 seconds to accelerate from 0-62mph and feels quite flat low down, so it's just as well that it's happy to rev.

For stronger performance, there’s the 369bhp M440i petrol. It has four-wheel drive and delivers whipcrack acceleration (0-62mph takes just 4.9 seconds) while making a more soulful noise. Still want more? To read about the fastest variant, see our BMW M4 Convertible review.

Whichever engine you choose, you get an automatic gearbox that makes slick changes, especially in Sport mode. You can take control yourself using the shift paddles mounted on the steering wheel.

Lopping the roof off a car often makes its structure rather floppy, and while you’ll see the 4 Series Convertible's rear-view mirror wobbling sometimes, it takes a big bump for any shake to come up through the steering column. Thankfully, the steering remains as precise as it is in the coupé, allowing you to place the nose of the car exactly where you want it.

BMW's M Adaptive Suspension is available as a standalone option regardless of which trim you go for. That lets you stiffen or soften the ride by selecting different modes, and even Comfort mode does an excellent job of propping up the body during hard cornering.

In fact, on pockmarked and uneven B-roads, Comfort is a better bet than the more focused Sport setting because its extra suppleness stops you from being bounced off course.  

It’s fair to say that the Porsche 718 Boxster is more involving to drive, but that car is smaller and misses out on the two rear seats. Compared with the Mercedes CLE Cabriolet and VW T-Roc Cabriolet, the 4 Series is far better. 

Whichever driving mode you select, the car has an agility that's surprising given its extra weight compared with the coupé, and a comfortable ride, even with the big optional 19in wheels fitted. It rounds off all but the nastiest bumps and potholes, and deals with undulating tarmac with a great balance of comfort and control, making this a car you’d happily cruise around in all day. 

We’ve yet to try the 4 Series Convertible's standard suspension set-up but we have tried it with the optional M Sport suspension, which comes with the M Sport Pro pack and adds stiffer springs and tweaked dampers. Effectively, it makes the 4 Series Convertible feel like it’s in the adaptive version’s Sport mode but doesn’t take away from the overall comfort. 

When it's in place, the fabric roof does an excellent job of keeping noise down, with only a bit of wind whistling from around the front windows and engine noise that settles down when you’re not pushing on. Our only real demerit is that there’s a fair amount of road noise filtering up through the floor. 

If you drop the roof of the 4 Series Convertible but keep the windows up, you won’t arrive at your destination looking like your hair has had a close encounter with a hurricane. You’re even more protected if you fit the removable wind deflector, although you won’t be able to use the rear seats when you do.

For some extra luxury, you can add an optional Warm Air Collar – basically, vents in the front seats that blow warm air on to your neck. 

"As someone with long hair, I don’t usually get to enjoy convertibles for fear of being blinded by my fringe. The 4 Series is different and never proves blowy with the roof down, even at motorway speeds." – Dan Jones, Senior Reviewer

When you're inside the 4 Series Convertible, you’d be forgiven for thinking you’d accidentally got into a BMW 3 Series. The driving position is almost identical, as are the dashboard and infotainment system.

In many ways, that's great news, because it means you get a comfortable and supportive driver’s seat with lots of adjustment, as long as you add optional adjustable lumbar support, which comes as part of the Comfort pack.

Forward visibility is good, with windscreen pillars that are slim enough not to get in the way at junctions.

Rear visibility isn’t great with the roof up because the rear headrests block much of the small rear screen, and there’s a lot of canvas obstructing the view over your shoulder. At least front and rear parking sensors come as standard on all models, along with a rear-view camera.

All versions come with bright adaptive LED headlights, which can maintain maximum illumination without dazzling drivers ahead of you. 

Build quality is first rate, with only the odd bit of hard plastic, most notably the bottom spoke on the steering wheel, and some silver-painted buttons on the dashboard letting the side down a little. 

The driver gets a 12.3in digital driver's display as standard with all trim levels. It shows lots of information, and is positioned right beside a 14.9in central infotainment display in the same housing.

You can operate the infotainment screen as a touchscreen or by twisting and pressing a rotary controller between the front seats, making it less distracting to use while driving, compared to touchscreen-only systems like in the Mercedes CLE Cabriolet. Annoyingly, adjusting the temperature and climate control system is more fiddly than before (the latest facelift got rid of user-friendly physical buttons below the air vents).

The infotainment system has plenty of features, including Android Auto and wireless Apple CarPlay smartphone mirroring, along with a DAB radio and built-in sat-nav, but that means the main menu is pretty overwhelming. Luckily, the system reacts quickly to your inputs and has permanent on screen shortcuts to all the parts you’ll use the most, helping to simplify things. 

Wireless phone-charging is available as part of the Comfort pack, as well as a very impressive 464W, 16-speaker Harman Kardon sound system (available as a standalone option).

"If you’re into your music, I think you’ll definitely want to add the optional Harman Kardon stereo system. It’s arguably one of the best systems out there, giving plenty of depth to your music." – Dan Jones, Senior Reviewer

Practicality isn’t going to be a top priority when buying a two-door soft-top like the BMW 4 Series Convertible, but the chances are you occasionally need four seats and a boot that can swallow more than just a shoe box.

There’s as much space up front for occupants in the 4 Series as you’d get in a BMW 3 Series so you’re unlikely to have any problems with head or leg room. That includes storage space as well, with a big glovebox and a decent cubby under the centre armrest.

There's a useful lidded storage area in front of the gear selector, where you’ll find a couple of generous cupholders and a space for your phone and keys. You also get partitioned door bins so loose items don't roll around.

Getting into the rear seats involves squeezing through a relatively narrow gap, but the same is true of all four-seat convertibles. Once you’re in, you’ll find acceptable leg room.

Taller adults will need to cower slightly or put up with their head resting on the underside of the roof, but a couple of six-footers will be comfortable enough in the back as long as the journey isn’t too long. BMW gives you a couple of cupholders back there but the other storage areas are pathetically small.

The boot capacity is slightly smaller than in the BMW 4 Series Coupé and – as with most convertibles – offers more space with the roof up than with it down.

There’s still space for up to six carry-on suitcases and you can fold down the rear backrest using a handy lever in the boot. Unlike in the coupé or the Mercedes CLE Cabriolet, the seats don't split and fold down for greater storage flexibility, but there is a cubby behind them where you can store the optional wind deflector vertically.

"I think it’s quite impressive how much space you have when sitting inside the 4 Series Convertible, especially in the front." – Dan Jones, Senior Reviewer

The BMW 4 Series Convertible costs more than the equivalent BMW 4 Series Coupé but less than the Mercedes CLE Cabriolet. The VW T-Roc Cabriolet is cheaper but nowhere near as good to drive.

It’s worth noting that, compared with those rivals, the 4 Series Convertible is predicted to lose its value slightly faster. That can have an effect on the amount you’ll pay if you’re buying on PCP finance, so make sure you get the best price by checking our new BMW deals page. 

Entry-level M Sport trim comes with plenty of standard kit, including 18in alloy wheels, leather seats (heated in the front), cruise control and three-zone climate control. It’s the one we’d go for but, in terms of options, it’s worth paying extra for adjustable lumbar support and the M Adaptive Suspension.

Sitting above the M Sport is the range-topping M440i. It gets similar equipment to the entry-level car but adds the more powerful engine and the M Sport Pro pack as standard, bringing M Sport suspension, an M Sport differential, sportier styling and different 18in alloys. Even with this version, you’ll still want to add the optional adjustable lumbar support and the adaptive suspension.

The latest 4 Series Convertible didn't feature in the 2023 What Car? Reliability Survey but BMW as a brand finished in 12th place out of 32 brands. That places it above Porsche, Volkswagen and Mercedes. Every 4 Series Convertible comes with a three-year/unlimited-mileage standard warranty, which matches what you’ll get with the Mercedes CLE Cabriolet.  

The model was tested for safety by Euro NCAP in 2019 and received the full five-star rating. It scored well, partly thanks to the model's standard collision-prevention equipment, including automatic emergency braking (AEB).

For more safety kit, you can also add the Driving Assistant as part of the optional Technology pack, adding lane-departure warning, rear cross-traffic warning, automatic speed-limit recognition and an upgraded AEB system that can recognise pedestrians as well as cars.

"While the 4 Series Convertible is pretty well-equipped as standard, even in our favourite entry-level version, I think it's quite annoying that you have to add lots of things as optional extras – especially adjustable lumbar support with the already expensive M440i." – Dan Jones, Senior Reviewer

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