We knew BMW->ke178 was working on a brand-new 5 Series->ke317 model since early 2014, when the first prototypes were spotted while being towed to a test facility in Europe. However, no test vehicle had hit the street on its own wheels recently, hinting that development was either slow or BMW had yet to reach that stage with an all-new platform on its hands. But with 2015 nearly upon us, the Germans finally took the next-generation sedan->ke142 out for a test run, providing us with our first look at the vehicle set to replace the F10 model. Sure, these spy shots aren't exactly revealing, given all that camouflage standing between our eyes and the body, but at least now we know things are well underway.

Very little is known about the upcoming 5 Series, but one thing that's 100-percent certain is Munich is using a brand-new platform for its Mercedes E-Class->ke373 and Audi A6->ke934 competitor. Much like the next-gen 7 Series, the upcoming 5 Series is going to fat camp to lose around 200 pounds for improved performance and better fuel economy. A fresh exterior design is also on the table, but don't expect anything radical as far as styling goes.

Click past the jump to read more about the 2017 BMW 5 Series.

BMW 5 Series - spy shots

Although it is camouflaged to the teeth, this prototype tells us a thing or two about the new 5 Series sedan. First of all, the Bimmer is getting a flatter and wider split kidney grille, which may result in a sportier appearance. And while there are no production headlamps to gaze at, we have a hunch they will be thinner and extend to the grille, a feat that's been introduced on several 2015 model year BMWs. The body also seems a tad wider and the wheelbase appears to be a bit longer, which means the Germans are aiming for enhanced legroom and shoulder room in the front and rear. What's particularly interesting about this test vehicle is that has an extra fuel cap on the left front fender, meaning we might be looking at the first hybrid version of the 5 Series.

Speaking of drivetrains, the sedan is in for quite a few changes under the hood. The midsize is set to receive the company's new family of modular engines, with the non-M models to use 2.0-liter four-pots and 3.0-liter inline-six units, both with turbochargers strapped to them. The hybrid model will likely get the tiny, 1.5-liter three-cylinder, and an electric motor for added power and instant torque. The M5, on the other hand, will use a revised version of the existing 4.4-liter V-8.

The redesigned sedan is expected to debut sometime in 2016 alongside its wagon sibling. Don't get your hopes up for a U.S.-spec version of the latter though.

Why it matters

We may have to wait more than a year to see the new 5 Series in the metal, but the fact that the sedan is already being tested on public streets is great news for BMW enthusiasts. Based on recent reports, the next 5 Series will be a turning point for the nameplate, and seeing the midsize being tested nearly two years prior to its debut speaks volumes about BMW's concern on everything going as planned. With Mercedes-Benz doing the same thing with the new E-Class, we're in for quite a battle starting in late 2016.