First up, a disclaimer. The 540i tested here wasn't exactly representative of the model we’ll see in the UK. Running traditional rear-wheel drive, it lacked the xDrive that will be standard on the 540i in the UK.
What is beyond doubt, however, is the new BMW’s outstanding refinement. From the first press of the starter button you’re aware of just how little engine noise enters the cabin. At low revs the operation of the turbocharged 3.0-litre straight six is barely noticeable, endowing the new 5 Series with a genuinely hushed character around town.
The positive impressions continue as you tick off the miles and discover the new suspension also manages to isolate road noise with far greater authority and with a more fluid feel than with the old 5 Series. Wind noise is also extremely low even at typical motorway speeds, adding to the overall impression of calmness.
The upmarket ambience brought on by the outstanding refinement and relaxed gait of the engine is reflected in a redesigned interior, which not only endows the new BMW with a more luxurious feel than its predecessor but also offers greater levels of accommodation, most notably in the rear.
The multi-layered dashboard shares its design and high-quality materials with that used by the 7 Series, while the centre console is angled ever so slightly towards the driver in a move recalling a key driver-centric interior element of earlier 5 Series models. The redesigned TFT instruments offer great clarity and alter in theme depending on the driving mode, giving the new car a satisfyingly contemporary air.
New engineered front seats with firmer cushioning also provide greater levels of support and comfort, making the new model a more pleasant place in which to travel long distances.
Among the more significant interior appointments is the latest generation of BMW’s iDrive infotainment system. It uses a new 10.3in touchscreen mounted on top of the dashboard and angled slightly towards the driver. As before, its redesigned menus can be operated via a rotary controller with a touch function. Alternatively, the new 5 Series offers standard touch as well as updated gesture and speech control systems from the 7 Series as an option.
Another noteworthy inclusion is BMW latest autonomous driving function, which allows you to perform lane changes between speeds of 44mph and 112mph at the simple application of the blinker without the need for steering input. It works well, accelerating, steering and, when necessary, braking the car on its own. However, it only allows brief periods of hands-off motoring before an alarm prompts you to take the wheel again.
Our test car came with adaptive dampers, which will be offered as a £985 option in the UK. So configured, the new 5 Series offers a noticeably more cosseting ride in Comfort mode than its predecessor, both around town and out on the open road.
Switch the 540i into Sport mode and it really comes alive. The Drive Experience function primes the throttle, engine, gearbox, steering and suspension to their most athletic settings, providing the 540i with pleasantly precise, engagingly willing and, in rear-wheel drive guise at least, entertaining traits. It’s rather quick, too. Official performance claims point to a 0-62mph time of just 5.1.sec, which makes the rear-drive 540i some 0.7sec quicker than the old 535i.
The key to this impressive turn of speed is a wonderfully harmonious combination between the engine and gearbox. The delivery is creamy smooth and, without any discernible turbocharger lag to talk of, extremely linear. There’s abundant torque throughout almost all of the rev range, and with it strong flexibility well into the business end of the dial. The shifts are satisfyingly rapid and terrifically smooth, both up and down the ZF-produced gearbox.
Predictably, the steering is quite weighty in the more sporting of the driving modes, but it is also satisfyingly direct. The added sharpness brought on by the integral rear steering system, as fitted to our test car, heightens the handling, adding a further touch of agility that helps to make the 540i truly engaging when pushed hard along a challenging back road.
The stiffening of dampers in Sport enhances body control, allowing you to carry considerably higher speeds with greater neutrality through open corners than in Comfort mode. This is further augmented by the adoption of faster-acting electronically controlled anti-roll bars in place of the older hydraulically operated units as part of an optional Dynamic Drive system.
The drawback of running in Sport, though, is a considerably harsher and less compliant ride that can sometimes limit the 540i’s progress on coarse road surfaces due to the suspension's inability to properly swallow mid-corner bumps with the same authority and suppleness as it does in Comfort mode. The inherent control remains, although the overall compliance is sometimes challenged by broken sections of bitumen, which occasionally send a nasty shudder through the body.