#bicycle performance

[cybeckhamcycling-blog]

Part Four: Smoothness of the Pedal Stroke Everyone knows that the bicycle pedal stroke goes in a circle, right? Unfortunately, while people hope it goes in a circle, it often goes in an oblong shape and

[nextlevelbmxdotcom-blog]

Bicycle Performance

I’ve used this picture on the site before, but it’s relevant again. Last night while working on my physics homework, I got to talking to my friend about efficiency. We got to talking about the most efficient machines, and I googled “most efficient machine.” The first link was the Wikipedia article for bicycle performance, which in the introduction stated that “investigators have calculated it to be the most efficient self-powered means of transportation.” Interesting. I read on…

According to the article “99% of the energy delivered by the rider into the pedals is transmitted to the wheels, although the use of gearing mechanisms may reduce this by 10–15%” which is astonishing compared to the efficiency of a typical car engine which is somewhere in the range of 20% on average.

What really got interesting is when the article talked about the energy of wheels. Through a series of equations they get at the general rule of wheels, which is that a pound of rotating weight is equivalent to two pounds on your frame. This all only matters though when you’re changing speed (ex: starts or in turns). If you’ve ever read any of the Rennen tech articles in Pull this is all old news though.

My favorite part is when it explains the weight of components on the bike in non technical terms. The placebo effect: “Since the rider feels that they are on better (lighter) equipment, they push themselves harder and therefore go faster.” This is all too relevant in BMX. Do you really notice that the difference when you drop a few ounces off your frame? Do those new handlebars really make your form better?

I just thought it was interesting. If you’re into physics and such you’ll like it too!

  http://gd.is/OJQDUr