2021 BMW 4 Series convertible: Bigger footprint, soft top

BMW's redesigned 4 Series convertible receives more oomph under the hood and a smarter suite of safety and driver-assist technology.

The 2021 BMW 4 Series convertible arrives in U.S. stores in March with a starting price of $54,095, including a $995 destination fee.

Since BMW introduced the first 3 Series convertible in the 1980s, the four-passenger droptops have become staples among young, upper-middle class drivers, said Sam Fiorani, vice president with AutoForecast Solutions.

"As more and more of these buyers have shifted to crossovers, the choices for those who like to put the top down have been slowly dwindling," Fiorani said. "This generation of the 4 Series convertible could be among the last of the breed, closing the roof on upscale wind-in-your-hair four-passenger cars."

Powering the new 430i and 430i xDrive convertibles is an updated 2.0-liter four-cylinder TwinPower turbocharged engine delivering 255 hp — an increase of 7 hp. The 430i accelerates from 0 to 60 mph in 5.9 seconds.

The M440i and M440i xDrive convertibles are powered by a 3.0-liter inline six-cylinder TwinPower turbocharged engine producing 382 hp — an increase of 62 hp. The M440i accelerates from 0 to 60 mph in 5 seconds.

A new 48-volt mild-hybrid system is standard on the six-cylinder M440i and M440i xDrive models. The 48-volt starter-generator unit is coupled with a 48-volt battery.

Energy can be recuperated from deceleration, braking and excess electricity generated while driving in Sport mode. Excess energy is converted to electricity by the starter-generator and stored in the battery. The energy can be used by the starter-generator to boost performance during hard acceleration or by providing power for electronic systems.

The second-generation 4 Series convertible switches from a hard top to a soft top. The fabric top, which is about 40 percent lighter than the previous generation's hard top, increases cargo space and lowers the vehicle's center of gravity, BMW said.

The 2021 4 Series convertible is 5.2 inches longer (5.3 inches for M440i models), 1 inch wider and 0.1 inch higher. It also has a 1.6-inch longer wheelbase than its predecessor.

The new BMW kidney grille design is angled forward and extends to the bottom of the front bumper cover. The kidney grille is framed by a three-dimensional mesh structure. The arrow-shaped lines of the hood come together at the grille while the air curtain intakes at the edges of the front bumper highlight the 4 Series' width.

Slim LED headlights taper toward the grille. Slim, darkened L-shaped LED taillights extend into the quarter panels.

Optional on the new 4 Series is the Driving Assistance Professional Package that offers Extended Traffic Jam Assist for limited-access highways — a Level 2 autonomous assist system which helps reduce fatigue in freeway traffic by allowing for extended hands-free driving.

A new optional feature on 4 Series models equipped with the Parking Assistance Package uses the driver-assistance system cameras to record video from the front and rear of the vehicle.