The X7 was not the only model BMW was testing around the Nurburgring. The fourth-generation X5 was also seen at the Green Hell and it appears BMW was busy testing the vehicle's on-road capabilities.

According to our spies, the next-gen X5 was doing quick laps as BMW wanted to see how the car handled around the track. From the looks of things, the all-new X5 was quite nimble around the track and appeared stable around the tight bends.

Spied: Next-gen BMW X5 heads to the Nurburgring

As for its looks, the all-new X5 prototype still bears the heavy camouflage from before but we do get to see some slight changes from the previous generation. Up front, it gets a larger kidney front grill which we'll also see in other crossover models.

While it does have the production body, it still has the faux headlights and taillights. This could mean that BMW is still finalizing the design of the aforementioned components. Size-wise, our insiders also mentioned that the new X5 will be slightly bigger than the third-generation model.

The rear quarter of the fourth-gen BMW X5 prototype

As for its underpinning, the new X5 will apparently be using the new OKL platform. First used in the G12 7-Series, it features a mix of aluminum, magnesium, steel and carbon reinforced polymer, the same kind of material used in the i3 and i8 plug-in hybrid models. With the lightweight platform, BMW expects to reduce the X5's curb weight by as much as 300 kg.

A closer look at the rear of the next-gen BMW X5

It is highly likely that a range of TwinPower Turbo inline-sixes and inline-fours will make their way in the fourth-gen X5. A plug-in hybrid powertrain could also make its way in the new crossover.