2021 BMW 4 Series Convertible Brings Back the Soft Top

The new 4 Series looks so much better with the roof sawed off.

BMW

Thirty-five years after the introduction of the first BMW 3 Series Convertible was unveiled, BMW brought back the soft top for the 3er's modern-day successor, the 4 Series Convertible. 

The last generation 4 Series convertible was only available as a folding hardtop, which was fine enough, but also pretty heavy and bulky up top, eating into cargo space and messing with the handling. 

BMW

According to BMW, the new soft top is approximately 40 percent lighter than the last-gen's hardtop, adds 0.2 inches of additional head room and adds 1.2 cubic feet of extra cargo area for a total of 9 cubic feet of stuff space. There's even a safety mechanism that prevents it from being lowered with a full trunk, and a pass-through in the rear seat to haul longer items if need be. The rear seats are designed for two with a center console in the middle. 

There are two colors available for the top: a standard black and an optional Moonlight black that has a subtle shimmer to it. 

The soft top material pulls taut when it's closed to reduce wind noise and improve the car's aerodynamics. It features a honeycomb-design construction, multiple layers of insulation and a glass rear window. It has three bow panels that fold into an accordion-style Z configuration when open and tucks under a hard cover. 

BMW

The soft top can be opened and closed at up to 31 mph, and takes just 18 seconds to do either. You can also open the top using the optional Comfort Access system through the remote key. 

When the top is down, there's a standard wind deflector with two mesh elements that reduces wind noise and turbulence. It comes with its own fitted bag in the trunk or it can fit behind the rear backrest.  

Aerodynamics were important here, with a coefficient of drag that improved by 0.02 due to its new soft top, an underbody that's nearly sealed and other aerodynamic aids like air flap control and air curtains. This is despite the fact that the car itself is bigger: 5.2 inches longer (or 5.3 inches for the M440i Convertible), 1 inch wider, 0.1 inch higher, and with a 1.6-inch longer wheelbase. 

BMW also worked to make up for the rigidity that was lost when they took the 4 Series' roof off by adding an aluminum shear panel in the front end, a rigid rear floor plate, a reinforced transmission tunnel in the rear and side skirts that have greater torsional rigidity. The company says that all of these tweaks make the new 4 Series Convertible 4% stiffer in terms of static torsional rigidity than the last 4 Series Convertible. 

Part of the 4 Series Convertible's extra rigidity was added for safety. In addition to the reinforced steel side skirts, there are high-strength side impact members in the doors and seat cross-members to protect against side collisions. When the car senses the possibility of a rollover, two high-strength aluminum roll bars deploy in just a fraction of a second from behind the rear seat headrests using a pyrotechnic charge. 

BMW

Yes, it, uh, has that grille. You know the one. BMW says it provides "adequate airflow to meet engine cooling requirements." I mean, it's the size of Connecticut, so it better. 

Yet somehow it looks more like a BMW than its hardtop counterpart. The standard 4 Series hardtop looks like a Generic Sporty Coupe design, and the minor bend in the C-pillar couldn't save it from looking more like an Altima coupe from certain angles. Sawing the roof off seems to have solved that. (Do the kidneys next, please?)

The M Sport Package for the 4 Series Convertible adds a restyled front bumper with larger air intake openings, a different rear bumper with shadowline inlays, plus high-gloss black finishes for the front air intake trim, side window moldings, lower exterior mirror housings and rear diffuser panel. The Shadowline Package adds high-gloss black finish to the exhaust tip trim and kidney grille, plus a black finish on the mirror caps. 

The M440i Convertibles get a Cerium Grey finish on the front intake trim, rear trapezoidal exhaust tip trim, kidney grille and exterior mirror caps. So, you can have the grille in multiple ways, so long as you have...the grille. (At least it's a lot more subtle than the M4's.)

BMW

Inside, BMW's tradition of driver-focused interiors continues, with the main dashboard controls angled slightly towards the driver. BMW's power Sport seats and leather Sport wheel are standard. The M440i convertible and those with the M Sport package get the M Sport steering wheel, M logos on the door sills and extra soft knee padding on the center console. There's even optional interior ambient lighting to highlight the contours of the interior, and you can set the color using the 4 Series Convertible's iDrive infotainment system. 

A lot of extra effort was put into acoustics here, with the convertible receiving extra noise reduction tweaks to the engine cover, underbody and intake system. Likewise, BMW reduced the amount of airflow system in the air conditioning system. A three-zone automatic climate control is standard on the car. 

The rear-wheel-drive 430i Convertible starts at $53,100, with an all-wheel-drive 430i xDrive Convertible ($55,100), rear-wheel-drive M440i Convertible ($64,000) and all-wheel-drive M440i xDrive Convertible ($66,000) all as drop-top options. The extra little nugget in there is a non-AWD M440i, which wasn't available at the hardtop's launch. 

Drivetrain-wise, expect the same as you'll get in the standard 4 Series. The 430i gets the 255-horsepower turbocharged 2.0-liter four-cylinder B46 engine, and the M440i has a 3.0-liter turbocharged inline-six B58 engine mated to a 48-volt mild hybrid system, good for a combined 382 hp. The rear-wheel-drive 430i Convertible rockets from 0 to 60 mph in 5.9 seconds, and the rear-wheel-drive M440i Convertible does it in 5.0 seconds. (BMW did not give times for the xDrive variants as they were listed as to-be-determined.) All 4 Series Convertibles have an electronically limited top speed of 155 mph or 130 mph depending on their wheel and tire package. 

Sorry, manual fans—as with the hardtop 4 Series, an 8-speed automatic transmission is the only available transmission. At least it'll look good when you see it from behind. 

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