Rivian founder R.J. Scaringe took to social media to tease the company’s upcoming Enduro electric drivetrain.

This system is designed and built by Rivian in-house rather than purchased (at what is said to be a high cost) from Bosch.

The Enduro-equipped dual-motor all-wheel-drive R1S SUV with the optional Max Pack will provide 390 miles of range while preserving the crucial third row to provide seating for seven passengers.

“This is something a lot of customers were excited about and wanted, so we put a lot of time and effort into making sure we could deliver this,” said Scaringe in a video posted to Twitter from his personal account.

Rivian will start delivering these Enduro-powered vehicles in about six months. “We’re going to start deliveries of this configuration in the fall with the Enduro drive unit,” he said. “I’m excited about it and I know there are a lot of customers out there who will be excited to get this configuration.”

Rivian’s Dual-Motor AWD features two single-motor Enduro drive units — one on the front axle and one on the rear.

The motor, gearbox, and inverter are developed and manufactured entirely in-house by Rivian in an impressively compact package. This configuration uses different front and rear gearing to boost torque to the rear wheels, so the vehicle will have a rear-drive feel and tow ratings of 11,000 lbs. for the R1T and 7,700 lbs. for the R1S.

These vehicles use conventional brake controls to manage left-right torque distribution, whereas the existing quad-motor models using the Bosch-supplied motors are able to apply power to each wheel individually from its own dedicated electric motor.

Dual Motor

Quad Motor

An optional software upgrade to the Dual-Motor AWD system boosts power and acceleration, delivers approximately 700 horsepower (vs. 600+ hp for Dual-Motor AWD), and more than 700 lb.-ft. of torque (vs 600 lb.-ft. of torque for Dual-Motor AWD), and acceleration from 0-60 mph as quick as 3.5 seconds (vs 4.5 seconds for Dual-Motor AWD).