The third-generation Fortwo has grown 100mm wider, but aside from that the new car is sized practically line-ball with the outgoing model. The new Fortwo measures 2690mm from head to tail and sits on a 1873mm wheelbase. The Forfour, meanwhile, has a length of 3490mm and a 2494mm wheelbase. Both cars are 1660mm wide and 1550mm tall.
Boot space in the Fortwo is 260L, while the ForFour has a 185L trunk. The Forfour's rear seats can be folded down to accommodate a total of 975L worth of cargo.
The new Fortwo, like its forebears, features a two-piece tailgate, while the Forfour utilises a more conventional one-piece design. Ingress and egress in the Forfour is aided by rear doors that swing out to almost 90 degrees.
As with previous Fortwos, but unlike the Mitsubishi Colt-based first-generation Forfour, the new Smarts have a rear-engine, rear-wheel drive layout. The new cars will be initially available with a 52kW/91Nm 1.0-litre three-cylinder petrol engine and a 66kW/135Nm turbocharged 0.9-litre three-cylinder petrol. These two engines will be joined later by an entry-level 45kW motor.
There's good news for anyone who's endured the current car's automated clutchless manual gearbox: the new generation Fortwo and Forfour's gearbox options are a five-speed manual and a six-speed dual-clutch transmission.
Equipment available on the new Smart range includes LED driving lights, cruise control and speed limiter, and heated seats. Depending on the trim level, the new Smarts are fitted with either a large monochrome or colour LCD screen in the centre of the instrument cluster.
A mechanical power steering system is fitted as standard, but upscale models are equipped with a variable ratio electric setup.
Driver, passenger, head-and-thorax and knee airbags are fitted as standard throughout the range, as is crosswind assistance. Optional safety gear includes forward collision warning and lane keeping assistance.
All of the available entertainment systems reside in a pod that protrudes out of the Smart's dashboard. Lower end versions can be equipped with a smartphone holder, while top-shelf systems feature a large touchscreen and satellite navigation.
The top-spec JBL audio system is equipped with eight speakers and a six-channel 240W amplifier in the Fortwo, and 12 speakers and an eight-channel 320W amp in the Forfour.
Buyers can personalise the new Smart range extensively, with the company claiming that there are around 40 different exterior colour combinations available. On the inside, a large portion of the dashboard and door trims are covered in a unique mesh fabric, which can be ordered in a variety of eye-catching colours.
Given the brand's low profile and sales in Australia, it's not clear whether the third-generation Fortwo and second-generation Forfour will make the journey down under. Regardless, the new Fortwo will go on sale across Europe this November at roughly the same price point as the outgoing model; the Forfour will be around 600 euros ($865) more expensive than the equivalent Fortwo.
Click the Photos tab above for dozens of images of the new Smart Fortwo and Smart Forfour.