Even Tesla CEO Elon Musk has conceded that the company's electric Model X crossover utility vehicle ended up a more complicated vehicle than may have been necessary.

Now, a lawsuit by Tesla Motors against German supplier Hoerbiger Automotive Comfort Systems describes the difficulties of developing the big SUV's signature rear "falcon doors."

Tesla sued Hoerbiger to stop it pressing claims for payments after the electric-car maker cut all ties to the supplier in May 2015.

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The process of developing the falcon doors is part of a story published yesterday in The Wall Street Journal, which notes several suppliers competed to develop the vertical doors.

While electric range, towing capacity, and the unique doors all likely contributed to the multiple delays in Model X production, the doors may have played the major role.

2016 Tesla Model X launch in Fremont, California

2016 Tesla Model X launch in Fremont, California

According to the Journal's summary of the lawsuit filed in the U.S. District Court for Northern California, Hoerbiger received a development contract more than two years ago.

But, the suit alleges, the company repeatedly failed to deliver working prototypes of a door system that met Tesla's engineering standards between March 2014 and May 2015.

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At that point, Tesla cut ties to Hoerbiger, a supplier of hydraulic garage-door systems.

The company is asking that the court compel the German supplier to state that it didn’t breach any contracts, to stop demanding further payment, and to pay Tesla both damages and attorney fees.

2016 Tesla Model X

2016 Tesla Model X

Tesla ultimately had to abandon Hoerbiger's work altogether, the lawsuit alleges, designing and testing its own electromechanical door system and then hiring a new supplier to build it.

That required Tesla to absorb the "costs of re-tooling the entire vehicle in order to support a different engineering solution,” it says.

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In February 2012, first deliveries of the electric SUV were promised for December 2013. Then in March 2013, the company said it would "slightly" push back that date--a full year, to December 2014.

In February 2014, CEO Musk hedged a bit further, saying that deliveries would actually start in March 2015. Further delays followed quarter by quarter.

2016 Tesla Model X with 2011 Tesla Roadster Sport, photographed by owner Bonnie Norman

2016 Tesla Model X with 2011 Tesla Roadster Sport, photographed by owner Bonnie Norman

The Model X finally struggled into production during the last quarter of last year; the company says 507 were built by December 31, of which 208 were delivered to buyers.

As of the last week of December, Tesla wrote, the "daily production rate [was] tracking to production of 238 Model X vehicles per week."

[hat tip: Brian Henderson]


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