Spartanburg, South Carolina - In what is shaping up to be one of the most intensive teaser campaigns in  automotive history, BMW has released a whole album of photos, not of the production version of its big new X7 SUV, but of the the assembly of the pre-production test mules.

The ‘real’ X7 isn’t due for release until the end of 2018.

The X7 will bring the total range of BMW SUVs produced at Spartanburg to five, and will be built on the same assembly line as the current X5 and X6 - as are this series of test mules, while a specially trained team sorts out any glitches in the production process, and trains the staff who will build the new X7.

The pre-production mules - each camouflage-wrapped with conspicuous striped patterns at the factory to conceal the new model’s styling for as long as possible - will be handed over to the  development department for endurance testing in extreme conditions, such as the desert regions of Death Valley or the ice and snow covered slopes of Scandinavia.

Some will also be used for homologation and type approval inspections in the various markets around the world where the X7 will be sold, so that by the time production of the final version gets underway in the fourth quarter of this year, any potential problems will have been ironed out, the staff at Spartanburg will know exactly how to build them and the X7 will be certified street-legal in every market where BMW plans to sell it.

We were surprised to learn that the Spartanburg complex is BMW’s biggest plant worldwide. Its 9000 workers roll out 1400 X3, X4 X5 and X6 SUVs every day - that’s about 450 000 cars a year, of which about 70 percent are exported, making BMW the biggest vehicle exporter in the United States by value.