New BMW M440i Convertible 2021 review

Verdict

While this open-top M440i Convertible can’t 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. Few other cabriolets manage to 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. We’ll leave the verdict on its styling up to you.

BMW has bolstered its open-top range with the new 4 Series Convertible. While most buyers choose a drop-top to enjoy open-air motoring, the most significant change to this G23 generation comes when the inevitable UK weather hits.

That’s because this new version has ditched the old car’s folding hard-top and replaced it with a fabric item. BMW argues that the complexity and packaging issues that came with that old roof are no longer worth it when a canvas top can keep the peace in the cabin just as effectively – 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.

As a result, the latest 4 Series Convertible is more practical than ever. While boot space with the roof up has increased by a modest 15 litres (now 385 litres) over the old car, the significant improvement comes when it’s folded; the new model offers 300 litres, 80 more than before.

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The cabin design is identical to the 4 Series Coupé’s, with the same fantastic infotainment, flawless build quality and sporty driving position. The seats gain ventilated head rests that can blow warming air on your neck on a cold roof-down outing. But it’s more cramped in the two back seats; the back rest is more upright and shoulder room is down compared with the Coupé.

Under the bonnet, the 4 Series is offered with two diesel and three petrol engines. Both diesel options each get an 11bhp mild-hybrid boost; there’s a 187bhp 420d and a 430d with 282bhp and a hefty 650Nm of torque. The petrol side of the family includes 420i and 430i models, with 181bhp and 242bhp respectively.

The 4 Series Convertible will soon be available in hot M4 form, but until then, this M440i is as potent as it gets. It produces numbers that wouldn’t have felt out of place for an M4 a couple of generations back; the 3.0-litre turbo straight-six engine makes 369bhp and 500Nm. Like the diesels, it uses mild-hybrid tech to boost fuel efficiency, but there’s also four-wheel drive as standard.

Despite that slicker roof, there’s still a significant weight gain for the open-top model. While the M440i coupé weighs 1,740kg, the convertible adds 150kg. No surprise, then, to discover that the extra mass blunts performance, too. Not that the M440i is a slouch – 0-62mph takes 0.4 seconds longer than in the coupé, but a time of 4.9 seconds is still rapid.

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It’s a fantastic engine: strong, smooth and – now with the benefit of less material separating the driver from the exhaust – more tuneful than ever. It’s paired with a slick eight-speed automatic gearbox that works faultlessly when left to its own devices, and responds quickly using the steering wheel paddles.

You can feel that extra mass in corners, mind. Compared with the lighter 4 Series Coupé, the M440i Cabriolet doesn’t have the same delicate balance. What it does have is unflappable traction, great turn-in and solid body control. It’s still better to drive than any other four-seat cabrio on the market for similar money.

Despite this, it also 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. 

The Convertible costs a little over five grand more than the Coupé, so there is a sizable jump to get the open-air. The range-topping M440i costs £59,670, so it undercuts its closest rival, the Mercedes-AMG C 43 Cabriolet, which starts from £61,455. The Mercedes does have 16bhp more and is 0.1 seconds quicker from 0-62mph, but it isn’t quite as engaging to drive or any more refined.