Tesla’s Model S was a subject of a survey for Plug-In America which collected data from current early model owners. Based on the data, the research firm predicted that  two-thirds of early Model S electric-drive units may fail by 60,000 miles. This comes as bad news for the EV firm if  the prediction is even remotely accurate.

Drivetrains Of Most Early Tesla Model S Sedans To Fail In 60,000 Miles

Reliability issues with early Tesla cars

The Tesla Model S has won accolades and was the first vehicle to break Consumer Reports’ review scale. Despite that, it is a known fact that there have been many reliability issues associated with the early production years of the car.

Since Tesla is a young automaker, this does not come as a surprise. The issues in the more recent model years have been reduced by 50%, the company reported in November. Though the company has made improvements, there are still issues with the early vehicles that need to be dealt with by first and second-hand buyers and, ultimately, Tesla.

Data was run twice

Plug-In America — a neutral and non-profit party — on the basis of consumer-reported data, claims that up to 66% of earlier model year Model S drivetrains stand chances of failing by 60,000 miles, says a report from Green Car Reports. The survey covered 327 respondents or 1% of Model S owners in 2012 and 2013, while there were 43 owners of later model years (2014+). The sample data was run twice, says GCR.

Inquiries regarding several aspects were made, such as ownership experience, mileage, whether the drivetrain has been swapped, and if so, the mileage at the time of the repair. The conclusion of the study was that there were 250 suspends or samples that did not fail, while there were 77 drivetrains that failed in comparison.

The characteristic life was found to be 50,000 miles in the initial study conducted by a “reliability engineer,” while GCR worked the second study, making use of free online software. It made use of the final odometer reading of the study data, and the conclusion was that the characteristic life is 57,000 miles before a replacement of the drivetrain is needed.

On Wednesday, Tesla shares closed down 0.97% at $224.52. Year to date, the stock is up by almost 1%, while in the last six months, it is down by over 12%.