Inertia is explained in Newton’s first law of motion, which states that a body in motion or rest remains in motion or rest respectively unless an outside force is exerted upon it.

With respects to bicycling inertia can only be felt in two circumstances, when we first start riding and when we suddenly stop. The first case occurs when accelerating from rest, your body and the bike both want to stay at rest. The second case occurs when the bike suddenly stops but due to their inertia the rider continues to stay in motion.

This, by the way is a great way to really feel some frictional forces! All in the name of physics!