I thought this study by Specialized's aerodynamicist Mark Cote at the A2 Wind Tunnel and Lowe's Motor Speedway in North Carolina was interesting! 

And being a triathlete who loves numbers I thought I'd share with you. Knowing this, I thought I'd share a bikeradar article that looked interesting. http://www.bikeradar.com/gear/article/how-aero-is-aero-19273

Key points:

• Position: Going from drops to aerobars will save you ~30 watts at 40km/h

• Bike: A time trial bike will save you ~20 watts over a road bike with clip-ons at 40km/h

• Helmet: A time trial helmet will save you ~10 watts over a road helmet at 40km/h

You'll find pictures, stats, cost, video and more from this aero experiment. .It's an interesting study, though not perfect.

Enjoy,

Sara