It's official: the 2018 BMW M5 sports saloon will have a four-wheel-drive system as standard (called M xDrive), but as the new tag suggests, this is no ordinary all-wheel-drive setup. To explore it to the fullest, we joined BMW M's engineers at the company's test facilities in Miramas in France. Should purists be worried about the iconic M5 nameplate? In a word: no. We don't have the full picture yet, but the sixth iteration is shaking up to be one of the most impressive yet.
In the Metal:
Although we saw the 2018 BMW M5 in its complete form last December, we're sworn to secrecy until official images are released in the coming months, so there's only so much we can glean from the disguised and swirly camouflaged prototypes we drove for this test drive. It clearly rides lower and appears to have a wider track than the standard BMW 5 Series, while the wings front and rear, plus the bumpers, are expected to be unique. Naturally, there's a quad exhaust set-up at the back and large air intakes up front. We expect new 19-inch alloy wheels to be standard, with 20-inch rims an option. Oh, and it has a carbon fibre roof.
Inside, expect plenty of M details, such as special seats, pedals and instruments, and of course new switchgear to control all the driving settings. We can tell you that the eight-speed automatic transmission is operated by a chunky new shifter that has the parking button and three-mode Drivelogic toggle switch integrated into it, while there's also a new (perfectly round, you'll be glad to know) steering wheel with a thick rim and M1 and M2 buttons that are more conspicuously located on the spokes for easy access.
BMW M was purposely vague about most of the rest of the M5 so we'd focus on the M xDrive four-wheel-drive system, but we can't very well ignore it. Under the bonnet is a development of the twin-turbocharged 4.4-litre V8 petrol engine from the previous M5 and it sounds superb when you're pushing on. Conversely, it's a vague rumble in the distance if you're ambling about in Comfort mode, and there's a button specifically for the exhaust so you can choose how anti-social you'd like it to sound. BMW tells us only that the V8 produces 'around 600hp', so there's a gain over its predecessor, but nothing drastic. Nobody ever called that one slow, did they?
Those horses will have a little less work to do as the 2018 M5 is a little lighter than the old car, in spite of the extra hardware required for the xDrive system. The engine is bolted to an eight-speed automatic transmission (M Steptronic in BMW M speak), which replaces the old car's seven-speed dual-clutch M DCT unit. It's far smoother at all times yet seems to be as quick to change gear at full throttle with almost no discernible gap in power delivery. You can choose three levels of gear change speed and ferocity, whether in fully automatic (D) or manual (S) modes. In the latter, the transmission will not change up for you, even if you're bouncing the engine off the rev limiter. That's a very good thing in a car that might actually be taken on track.
The combination of more power and torque, a faster transmission and less weight helps the new M5 record a 0-100km/h time of 'less than 3.5 seconds', which is a significant second faster than its predecessor. The M xDrive system no doubt plays a large part in the off the line acceleration too, making it more effortless in more conditions where the previous car was quite traction limited. That's all very well and good, but while nobody wants a car that feels like it's going to kill you at the first corner if you press the accelerator too hard, BMW M buyers have come to expect a certain edginess and agility, and the M5 won't be an M5 if it turns out to be nothing more than a BMW M550i xDrive with a bit more go.
Worry not, as the M5's xDrive system is quite different to that of the M550i. Mostly because it has an electronically controlled Active M Differential at the rear axle and a central brain that integrates the sub-driving systems to ensure the characteristic 'M' feeling is present and correct. To that end, it can send anything from zero to 100 per cent of the engine output to the front or rear axles and then anything from zero to 100 per cent of the rear split to either of the back wheels. BMW M's engineers talk not of a target torque split between front and rear axles, but of a 'feed forward' strategy to make sure the car feels as the driver expects - like a high-performance rear-drive sports saloon, with the added security of four-wheel drive traction when it is needed.
How rear-drive the car feels is totally up to the driver too. If you hold down the Dynamic Stability Control (DSC) button, it can be turned off completely, which then allows the driver to choose from 4WD, 4WD Sport and 2WD settings. Pushing the M5 to the limit on a soaking wet handling circuit reveals how different these modes are. The 4WD setting (the default with the DSC switched on) is neutral and stable, easy to drive fast and very neat on the exit of a tight corner. It can be provoked into a four-wheel drift, but it requires a lot of space and dedication to do so. Brilliant for a cross-country blast in poor weather. The 4WD Sport setting ramps up the rear-drive sensation, and the car rotates in a wonderfully controlled and engaging manner, allowing power slides in the right conditions even, though with no nervousness or sudden sending of the engine's output to the front wheels to abruptly pull you straight. It's wonderfully judged and also accessible when you tap the DSC button once for the M Dynamic Mode.
The 2WD mode is for hooligans, basically, those that want to take their M5 on track and burn away their rear tyres. Or so you'd assume. In fact, driving the new car in this guise lays the base chassis ability bare, and it's an eye-opening experience, as it's far more benign and 'friendly' to drive than before, even in really wet conditions. The limits of grip are so well telegraphed now that you can choose to drive well within them or be that aforementioned hooligan. Do so and it's laughably easy to hold a slide. What's more, the quicker steering means it's easier than before to catch it before things get out of hand.
We realise that only a small percentage of BMW M5 owners will explore their cars to the limit on a circuit, but all this tomfoolery in the pre-production prototype has served several purposes. First up, it reveals that the new M5's chassis is a corker, mixing everyday civility with inherent stability and feedback. That it can also allow those that want to push things further carte blanche is something to celebrate. Still want that Mercedes-AMG E 63?
What you get for your Money:
We can't definitively say what the new M5 will cost nor what the standard specification will include, but it's a safe bet that all the driving systems and modes are included, as are 19-inch alloy wheels, leather upholstery and a full suite of infotainment systems. It will be interesting to see if BMW M fits the M5 with the company's latest semi-autonomous driver assistance systems, as they represent its latest technology, but they are also anathema to the M philosophy, I would have thought.
Our first taste of the 2018 BMW M5 was enough to assuage worries that the car would be sanitised by its new four-wheel-drive system. Those that really want rear-drive only need to press a button, while the vast majority will find the car easier and more enjoyable to drive more of the time. We can't wait to test drive the finished product later this year.