For the kind of driving in which most B-Class owners will engage, the 1.3-litre four-cylinder petrol in the B180 Sport performs creditably well. Throttle response is crisp in the context of downsized engines prone to turbo lag, and what limited power there is gets served up in a linear fashion. But bear in mind that outright performance for this entry-level model is modest, even if our B180 Sport did exceed its manufacturer’s claims in sprinting to 60mph in 8.4sec.
That puts it among comparably powerful premium hatchback rivals, although with relatively little torque, in-gear acceleration is uninspiring. The fourth-gear 40-60mph dash takes 5.7sec, necessitating the need to stray into the coarser, upper reaches of the rev range for any impromptu overtaking. And although it will spin all the way to 6300rpm, there’s little additional propulsion to be gained by pushing this engine past 5000rpm.
As in the case of the petrol-powered A200 we’ve road tested previously, Mercedes’ seven-speed dual-clutch automatic gearbox can put a fly in the ointment. Granted, in gentle driving, cycling through the middle gears, shifts are often almost imperceptible, but it will enthusiastically downshift a cog too far when only moderate acceleration is called for, serving only to highlight the engine’s poor refinement beyond 3500rpm.
Equally, this gearbox can operate with frustrating indecision during town driving and hesitate when stepping off the mark, as though the clutch has failed to engage properly. There is a manual mode, which can be temporarily engaged by pulling one of the wheel-mounted paddles or permanently set via the mode selector digital display, and with it the driver has more control of the gearbox machinations, but the extra effort required rather undermines the hassle-free brief of the B-Class.