2022 BMW 420i Convertible M Sport G23

A return to a fabric roof helps make the new 4 Series Convertible more desirable than ever

Words: Shane O’ Donoghue. Photography: BMW.

The new G23 is only the second-generation BMW 4 Series Convertible. In reality, however, its lineage can be traced all the way back to the 1978 Baur Cabriolet, based on the E21 3 Series. The open-topped car has evolved considerably in the intervening years, though the new 4 Series debatably represents a backwards step in one way. That is, of course, the ditching of the folding hardtop roof that was first introduced for the E93 3 Series Convertible – and continued into the first-generation 4 Series Convertible, the F33. In its place, the new 4 Series gets a fabric roof.

It’s not any old fabric soft top, though, as BMW’s engineers have pulled out all the stops to ensure that owners of the folding hardtop cars won’t feel like they’re compromising when it comes time to trade up to a new model. A quick glance at the new hood is all it takes to notice how smooth it is when raised – the usual joins and framework underneath are conspicuous only by their absence. That’s thanks to a new ‘panel bow’ structure using paper-honeycomb. When the roof is up, it’s pulled taut over these panel bow elements, smoothening out the overall profile.

Not only does this look great, but it’s also claimed to be good for aerodynamics and the reduction of wind noise. It’s not quite as silent on that last score as the 4 Series Coupé is, but it is more than acceptably civil at high speeds. Multiple layers of acoustic insulation are built into the fabric, too, which helps with that. Meanwhile, there’s a proper glass rear window and an extra five millimetres of front-seat headroom in comparison to the old car. Admirably, despite all this, BMW has managed to bring the weight of the roof down – by some 40 percent in comparison to the previous model’s folding hardtop. And there are two different colour options for the hood.

So yeah, it’s fine when you have to have the roof up, but there’s no point buying a convertible if you’re not going to drop the top at every available opportunity. Upgrade to the Comfort Pack for £1,350 to maximise that, as it includes a heated steering wheel, the excellent Warm Air Collar (heated air wafting through the headrest to your neck and shoulders) and a wind deflector, along with Comfort Access, more storage and extra USB ports.

Besides keyless access and other niceties, Comfort Access allows you to open the roof from outside the car, by just holding down the unlock button on the key fob. That allows you to wonder at the balletic movement of the various components as the roof folds and tucks itself out of sight. The operation takes just 18-seconds and it’s quiet. A button on the centre console can be used to lower or raise the hood at speeds of up to 31mph, too, which can be really useful. Meanwhile, a single button in the driver’s door allows raising or lowering of all four windows with a single touch.

No matter how precious you are about your hairdo, you’re unlikely to enjoy having all the windows and the roof down at anything over 40mph, as it’s seriously blustery. Nonetheless, the amount of wind buffeting in the front seats at motorway speeds is perfectly acceptable when the windows are raised – even without the optional wind deflector in place. For ultimate hairdo protection, it is recommended, though its use means you can’t carry rear passengers as you might expect.

If you really have to transport people in the back, they’ll find it quite cramped unless the front-seat occupants slide quite far forward, and the rear seatbacks are also very upright. Still, it’s entirely doable for shorter journeys, though it gets breezy back there from quite low speeds if the roof is down.

Many buyers will treat the rear seats as extra luggage space, but the actual boot isn’t at all bad. A through-load facility is standard to allow carrying of longer loads, while the new 4 Series Convertible holds 300-litres of luggage with the roof down, some 80-litres more than its predecessor — or up to 385-litres with the roof up, which is 15-litres more than before. To get the maximum volume, you must manually push up a plastic flap in the boot, which is easy to do, but it can be a little annoying the next time you come to drop the roof and discover you’ve forgotten to pull it back down into place. It’s a shame that can’t be done electrically.

Nonetheless, we have no complaints about the profile of the car – roof up or down. It’s a pleasingly flat rear deck that adds elegance to the 4 Series shape, with more than a hint of muscularity around the rear. The Sanremo Green Metallic paint is stunning, too, especially in bright sunshine. In the UK, the 4 Series Convertible is sold in M Sport specifications only, so all look good, with 18-inch alloy wheels at a minimum, though in our opinions the car looks much better with the black grille surround that comes with the Pro package or as part of the more expensive M Sport Pro Edition.

Our test car was the entry-level 420i model, powered by BMW’s turbocharged 2.0-litre four-cylinder petrol engine. On paper, the performance figures make for acceptable reading, as there’s 184hp and 221lb ft of torque on tap – and the latter is produced from just 1350rpm. But 8.2-seconds to 62mph from a standstill isn’t impressive and, sad to say, we found the performance to be quite underwhelming at regular road speeds. Despite the official figures, the car feels quite flat-footed at low revs, as if it needs much more torque to overcome the non-insignificant 1765kg mass.

Once on the move, it’s not a problem, and if you do extend the turbine-smooth engine to the redline, it feels rapid enough, but we suspect that most people that go for the base engine won’t drive their Convertible in such a manner, and hence might find the car lacking in oomph.

Perhaps this effect is heightened by the talents of the chassis. It sits on the same core platform as the 4 Series Coupé, with widened tracks front and rear and a significant increase in torsional stiffness – in comparison to the previous model. The Convertible gets additional reinforcement of the side sills, a new aluminium ‘shear panel’ at the front and other structural bracing to ensure it feels up to scratch. And it does. Even over a bumpy mountain road, it feels solid, allowing the suspension work as intended.

The Convertible is fitted as standard with the lift-related damping elements that debuted on the current 3 Series, configured specifically to suit the characteristics of the open car. These mechanically alter the damping force depending on the suspension travel, smoothening out smaller vibrations and reducing nervousness over particularly bumpy stretches of road. The Adaptive M suspension features Sport and Comfort settings, along with an Adaptive mode to automatically adjust the damping and other driving sub-systems. It all works wonderfully, enabling comfortable cruising if that’s your thing, or indecent levels of maintaining pace across country at the other end of the spectrum.

Which is perhaps why we found the 420i powertrain so frustrating. There’s no issue with the always-excellent eight-speed Steptronic automatic gearbox, of course, but this car is deserving of more performance. The 430i uses the same base 2.0-litre engine (both get a twin-scroll turbocharger, high-pressure direct injection, Valvetronic variable valve timing and double-Vanos), but with usefully more power, at 258hp, and torque uplifted to 195lb ft. It’s a full two seconds quicker to 62mph from rest, as well, which says a lot.

The G23 420d Convertible has the same amount of torque available, paired with 190hp, which should be more satisfying to drive than the 420i, despite a bit more weight and a less enticing engine note. That’s remedied in the other diesel option, the 286bhp 430d, which, budget allowing (it costs from £51,165), could be the best all-round mix between performance and effi ciency in the line-up. Or, if you want to go all out – and the M4 Convertible is out of reach – there’s always the M440i xDrive variant to consider, the only petrol version using a straight-six. It gets 374hp, all-wheel drive and a unique M Performance Vehicle makeover to help it stand out. And it manages to come in at a whisker under £60,000.

That’s quite a lot of choice from the cheapest at £45,800 to the most expensive, taking in modest and serious petrol power, two diesel engines, rear-wheel drive and all-wheel drive. The only thing missing is a manual gearbox. Other than that, buyers of the 4 Series Convertible can pick and choose as suits their needs – whether that’s ambling around town looking good or doing the same at more elevated speeds on the open road. Either way, BMW has undoubtedly moved the genre on, making the open-topped model more desirable than before.

2022 BMW 420i Convertible M Sport G23

• ENGINE: Turbocharged four-cylinder petrol, longitudinally mounted
• CAPACITY: 1998cc
• MAX POWER: 184hp at 5000-6500rpm
• MAX TORQUE: 221lb ft at 1350-4000rpm
• 0-62MPH: 8.2-seconds
• TOP SPEED: 146mph
• ECONOMY: 39.8mpg
• EMISSIONS: 162g/km
• WEIGHT (EU): 1765kg
• PRICE (OTR): from £45,800