The BMW X7 iPerformance Concept will be on display at the 2018 North American International Auto Show in Detroit in January, but pre-production versions of the new X7 series have now started to roll off the production line at the company's Spartanburg, S.C. plant in the U.S.

It therefore means the countdown is well and truly underway for the final 12 months leading up to the launch of the production version towards the end of 2018. In the meantime, this important new vehicle for BMW will be rigorously put through its paces in a variety of tests under partially extreme conditions.

Although plenty of spy shots of the new X7 have been circulating for some time, the official press release from BMW about the pre-production models now being built and tested is accompanied by images of the vehicle still in its black and white camouflage.

At the manufacturing facility in the U.S., the production of pre-series models is used to secure and optimize future series production. These BMW X7 pre-production models are already using the same assembly line as the current X5 and X6 models, where a specially trained team oversees the production process and qualifies the plant's employees for building the future production models.

The Spartanburg facility's boss, Knudt Flor, said, "We are proud to produce the BMW X7 here in Spartanburg, the home of our X models. This is a very special vehicle and our employees are looking forward to yet a further member of the X family. Together with the BMW X7, a total of five BMW X models will be exported from Spartanburg to all four corners of the globe."

Once off the assembly line, the X7s are handed over to development department specialists for homologation, registration, and for diverse testing purposes like endurance tests and test drives under extreme conditions. Locations used include the desert regions of Death Valley and the ice and snow-covered slopes of Scandinavia. While still on-site at the plant, the pre-production models are covered in a camouflage wrap with conspicuous striped patterns intended to conceal the final look to a certain extent.