Solid tires are maintenance-free. They are replaced when they become too worn or damaged. They can withstand punctures and debris, and still operate well. Pneumatic tires, on the other hand, risk failure due to punctures and debris. And even without damage that may cause a flat tire, they must still be checked and refilled with air regularly to keep them inflated properly.
Original Source: https://itstillruns.com/rubber-versus-pneumatic-wheels-7959001.html