Join Date: Oct 2004
Location: DC / Maryland suburbs
Bikes: Homebuilt tourer/commuter, modified-beyond-recognition 1990 Trek 1100, reasonably stock 2002-ish Gary Fisher Hoo Koo E Koo
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I've heard a top pro cyclist gets ~2 HP (for a brief sprint) out of a 180 lb. body: that's 0.011 HP/lb. On the other hand, a 2530 lb. Toyota Corolla CE
has a top power of roughly 130 HP: that's 0.051 HP/lb, significantly higher. CAR WINS.
A car--even one not designed for great power--definitely has greater max power per weight than a person. This isn't a very fair comparison though, because in a car designed for power, the engine can just be made bigger and stronger and heavier. Human bodies are designed to do a lot more than just generate power, and it's hard to optimize them for this specific purpose.
A more interesting comparison, I think, is the energy consumed per pound of weight per mile traveled... The book Bicycling Science
says that a human on a bicycle is the most efficient method of locomotion ever, by this standard. This kinda makes sense: a car has a lot of power, but it gets this power by being enormously heavy and not so aerodynamic, while a bike is explicitly designed to be light and aerodynamic.
Another interesting thing to compare would be cruising speed versus weight: on my road bike (total weight ~200 lbs) I can cruise at 20 mph quite comfortably. That's 0.100 mph/lb. On the other hand, that Toyota Corolla would probably struggle mightily at 120 mph. That's 0.047 mph/lb. BIKE WINS!
Basically, there are lots of ways to measure the relative performance of cars and bikes, and it seems to me that where efficiency counts (rather than raw power) bikes blow away the competition.