Solid tires (non-marking tires) are a type of tire that contrasts with pneumatic tires (hollow tires). Their carcass is solid, without a cord skeleton, and they do not require inflation, thus eliminating the need for an inner tube or airtight layer.
The earliest tires were solid tires. Currently, solid tires are only used on low-speed, high-load vehicles or machinery, and also on stationary machinery.