The second-generation 4 Series Convertible, codenamed G23, will join the Coupé (G22) in sharing engines with the new 3 Series, which will go on sale early next year. This means that beneath the fire-breathing M4, the range-topper will be an M440i-badged M Performance model with a 360bhp 3.0-litre inline six-cylinder petrol engine, flanked by a 320bhp M440d xDrive M Performance diesel equivalent.
These will go on sale shortly after 4 Series sales begin, although the Convertible is likely to arrive shortly after the Coupé. Non-M Performance versions of the 440i will also reach production, as will 430i and 430d mid-rangers. Models badged 420 will kick off the range, in both petrol and diesel forms.
BMW's xDrive four-wheel drive system will be available from the 420i upwards, as per the current 4 Series. It’s not yet known if BMW will offer a 4 Series equivalent to the 330e plug-in hybrid, but given the industry’s push to electrification and more stringent WLTP regulations in place, it’s looking increasingly likely.
Both cars will be based on the same CLAR (Cluster Architecture) platform as the 3 Series and other recent BMW models. This has resulted in weight savings of up to 50kg in the 3 Series. The new 4 Series Convertible is likely to exceed this figure over its predecessor, given its adoption of a far lighter cloth roof.
This means that the weight of the entry-level 420i coupé could dip as low as 1500kg, while the convertible will undercut the current car’s 1775kg considerably.
The new, lighter architecture will also likely improve handling, given its greater rigidity.
As per the new 3 Series, the 4 Series is unlikely to get the four-wheel steering system used on the new 5 Series, but BMW is making effort to improve chassis tuning and ride comfort.