At the CES trade show in Las Vegas in January, Lime showed off a new model of its electric scooter with thicker tires, color display screens between the handlebars and stronger aluminum to help the vehicles last longer. But months later, the custom-designed scooter, called Gen 3, is having problems of its own. The screens frequently crack or malfunction, and repairing brakes and other parts has proven complicated. Even the tougher metal has caused trouble—the additional weight makes it harder for workers to cart home scooters to charge overnight.

Scooter companies had pinned their hopes on sturdier hardware to help them slow their cash burn and demonstrate that the business can be profitable. But Lime’s experience shows how challenging that can be. Lime ended up slowing the rollout of the Gen 3 this spring, people close to the company said, even as its existing fleet faced maintenance issues. The previously unreported problems could further dent faith that Lime and other scooter companies can find a sustainable business model.