Tube is an inner part of the tyre which is a balloon like structure that can be inflated or deflated with a valve. This tube will be there on all bike wheels except tubeless wheels. When these tubes are inflated, it fills the gap between the inside of the sidewalls of the rim and tyre. Tyres are the outer part of tubes which is associated with wheels and rims. The role of air pressure in the tyre is to hold the fabric under tension, the contact point with the ground surface. At the contact point, the tread of the tyre is flattened against the road surface. Air pressure can only push directly outward, and so here, it pushes directly downward. The downward force of the air must equal the weight load, and so the area of the contact patch approximately equals the weight load divided by the air pressure. It’s very important to choose the right tyre and tube which suits the cycle.