Wheel & Tire Design
When bicycles were first invented, they had a large front wheel with a large radius. This made them extremely efficient and fast to ride on flat spaces, but unfortunately they were quite unstable and therefore very dangerous to the rider. The center of mass was very high and the bike overturned easily.
Any cyclist will know that there are different width of the bicycle tire depending on the terrain and intended use of the bike. Off road bikes have wide tires and on-road racing tires have very narrow tires. Why is this so?
The thin tires are suitable for road racing bikes as they minimize friction and cut back the weight of the wheel. However, these tires are not suitable for rough surfaces - the thin tire would sink into the valleys and increase contact and friction. The fat tires are wide enough to actually float above many of the dips and troughs in the ground, as they attach only to the high spots.
Tour de France cyclist Lance Armstrong, like many top cyclists, used technology to improve performance. Lance used a specially designed helmet for time trials. This is an event where maximum efficiency and speed is required. The helmet design helped to shave vital seconds of his time (probabaly so did his drug taking). The helmet minimizes friction by allowing air to flow over his head and down his back. An ordinary helmet would cause turbulent wind flow at his neck and create drag. He also wore specialized clothing to decrease drag.