Why does oiling the axles of a bicycle make move more easily?

When you oil the axles of your bicycle, you reduce the friction between the metal surfaces of the axle and the wheel bearing. This allows the wheel to spin more freely, which makes the bike easier to pedal. Friction is the force that resists the relative motion of two surfaces in contact. When you oil the axles, you create a layer of oil between the axle and the wheel bearing, which reduces the amount of friction between them. This allows the wheel to spin more easily and reduces the amount of energy required to pedal the bike.