• Six years after Elon Musk said Tesla had a next-generation Roadster in the works, he's again making promises that the car is on the way.
• "There will never be another car like this, if you could even call it a car," Musk wrote as part of a series of posts on X late Tuesday.
• Musk hyped the Roadster after Chinese rival BYD announced its supercar, the U6, would be delivered to customers this summer.

Six years ago, Elon Musk hyped a next-generation Roadster, the name of Tesla's debut car from 2008. A refreshed version was never produced, but Musk is once again promising a new Roadster is on the way.

"Tonight, we radically increased the design goals for the new Tesla Roadster," Musk wrote on X as part of a series of posts Tuesday night. "There will never be another car like this, if you could even call it a car."

"I think it has a shot at being the most mind-blowing product demo of all time," he wrote, adding that it will reach 60 miles per hour in less than a second, "and that is the least interesting part."

Musk promoted the next-generation Roadster concept at an event in November 2017, and in June 2018 in a series of tweets. He said at that time, "SpaceX option package for new Tesla Roadster will include ~10 small rocket thrusters arranged seamlessly around car." The engines would improve speed and braking, and may "even allow a Tesla to fly," he wrote at the time.

On Tuesday, he replied to his old tweets saying, "You will love the new Roadster more than your house."

Tesla didn't immediately respond to a request for comment.

Musk's renewed proclamations followed news that Chinese rival BYD introduced a new electric supercar, dubbed the U9, that can hit speeds similar to high-end models from companies like Ferrari.

BYD's electric supercar, which it says will be able to reach a top speed around 192 miles per hour, is slated for delivery to customers this summer. While BYD doesn't have plans to sell its vehicles in the U.S., Tesla competes with BYD in mainland China and other markets.

Tesla's market share in China declined in January to 6.1%, while BYD's share stood at 29.2%, according to data from the China Passenger Car Association cited by Morgan Stanley China Autos researchers in a note Wednesday.

Grandiose promises from Musk are nothing new. His frequent failures to deliver on them are the subject of an online promise-tracking website called ElonMusk.Today. The site noted on Wednesday that it's been, "1,876 days since Elon Musk said the new Roadster will use rocket technology that will allow it to fly."

In Tesla's most recent quarterly shareholder update, the company said the new Roadster is still "in development" with no pilot production line built and no chosen location for production.

"Musk is the master of selective disclosure of information," said Warren Ahner, an automotive tech expert and former competitive driving instructor.

Ahner said it's not clear how a supercar would benefit Tesla's business, adding that it's "mostly for ego."

"If you have the right credit score, you can walk into a Tesla showroom and buy a Model S Plaid today," Ahner said. That "already has way more power potential than 99% of drivers on the road are capable of handling."

Ross Gerber, a long-time Tesla fan and recent Musk critic agreed that it would be hard to "move the needle" for Tesla with a refreshed Roadster.

"If they make a great car that people will talk about, there could be a halo effect" said Gerber, CEO of wealth management firm Gerber Kawasaki. He compared it to the recently released Cybertruck. "Everyone wants to look at it and stuff," Gerber said. "But does it mean that it will help Tesla sell other cars?"

Gerber said Tesla should be focusing more on its affordable EV, which it calls its "next-generation" platform. He added that Musk's outspokenness on political matters "has been really detrimental" to the company and shareholders.

"I don't think he's focused," Gerber said. "And I don't think he tries at all to sell cars. It's put Tesla in a really tough position where we had to lower our investment in Tesla because we don't feel the opportunity is as good now that Elon has turned off so many of the company's core customers."

On Musk's X account, which claims 174.1 million followers, Musk has recently denounced immigrants and disparaged diversity, equity and inclusion initiatives in medicine and other fields.

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