"An inner tube is an inflatable ring that forms the interior of some pneumatic tires. The tube is inflated with a valve, and fits inside of the casing of the tire. The inflated inner tube provides structural support and suspension, while the outer tire provides grip and protects the more fragile tube. They are widely used in bicycles and are also used in many motorcycles and heavy road vehicles such as trucks and buses. They are now less common in other wheeled vehicles because of the benefits of having no tube, such as the ability to operate at low pressure and at high pressure (unlike a tube tire, which would pinch at low pressure and burst at high pressure), without going flat. Large inner rings also make effective flotation devices and are widely used in the leisure activity of tubing." - (en.wikipedia.org 27.04.2021)
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