This past weekend, SWMBO and I delivered my daughter's 21-speed full
suspension mountain bike (XMAS present) to her at her Humboldt State University
address from southern California. It was mounted to the trunk with a strap-based
temporary carrier. The Vehicle in question is our 2005 BMW 330i with performance
package. Average velocity along interstate 5 was 80.6 mph as reported by the
computer and BMW nav system, with a high speed of 95 and a low of 44. Trip fuel
economy from SoCal to Arcata was 19.8 mpg of premium at $3.76 per gallon
average. Trip economy for the return venture was 28.4 mpg with an average speed of
82.3 mph. Same tires, same roads, no attempt to resolve net height
variations, temperature differences, precipitation levels. Probable weight delta of 22
pounds less for the return trip given the removal of bike and carrier, but
addition of arctic temperature clothing.

Take Home Lesson: 30% fuel economy loss at average speed of 80 mph with
mountain bike perpendicular to direction of propagation. Not a lot of surface area.
Large effect.

For your amusement and perusal.

Frank Grunthaner

**************
Start the year off right.  Easy ways to stay in
shape.

http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489