Podcast: Aerodynamics With Dave Ripley

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In addition to working for Zipp, David is also a bike fitter and consultant for 51 SPEEDSHOP.

Topics discussed include:

• The Four restrictive properties working against you on the bike are:

1. Aerodynamics 2. Gravity 3. Drivetrain Friction 4. Road Friction

• 75-80% of aerodynamic drag comes from the body. The wheels are the second greatest source of drag. Components are next, and the frame is last.

• Weight doesn’t become a significant factor until the grade hits 6% for an extended period of time.

• A good clincher and latex tube compared to a poor tire and a butyl tube can result in a 10-11 watt difference per tire.

• He recommends air pressure of 100psi for a 150 pound rider on a tri bike on a smooth road. On a rough road a slightly lower tire pressure is recommended.