bike
esiegel | August 19, 2012“If you want total security, go to prison. There you're fed, clothed, given medical care and so on. The only thing lacking... is freedom.” -Dwight Eisenhower
One of the greatest feelings is the freedom to travel, whether by your own power or a mechanical motor, far faster than your own legs can take you. Kimya Dawson understands how delightful this is (and how much is missing when you can't have it), as you can likely tell from her song,
My Bike
I've always loved the feeling of biking, fast, along a deserted road, feeling the wind rush past me and seeing the world go by.
Image credit: Flickr…
rallain | July 23, 2010Check this out - NY Times: No Motors, but Mistrust at Tour de France.
So, the short story is that some people claim that Cancellara is cheating by putting a hidden electric motor in his bike. Now they are going to do random hidden-motor checks.
I have analyzed this motor-in-a-bike already:
Energy in a hidden battery: The short answer is that you could get about 500 watts for about 1.5 hours with a hidden battery that weighs 1.6 kg. Doable, yes. Advisable? Probably not. Also, you would probably hear the motor being used.
Do bikers cheat? In this post I look at some clips of Cancellara…
rallain | June 11, 2010Back to the discussion about hiding an electric motor in a pro racing cycle. Before, I looked at a video of Fabian Cancellara to see how his speed and acceleration compare to other bikers. The claim on the internet is that he pulls away so fast that he must have a motor hidden in his bike.
Just to be completely clear, I don't think he is cheating. Then why bother? If you ask that then this must be the first time you reading this blog. I welcome you. No, but really, this is what scientists do. How hard would it be to cheat?
From my analysis, it seems that a person could ride like he…
rallain | June 8, 2010Well, maybe that isn't the best title. You see, there is this video going around saying that it is possible that a professional bike racer was cheating by putting a hidden motor in his bike. I am not really going to talk about the cheating aspect (my gut feeling says that it would be too easy to catch, so he is not cheating).
Actually, there was an interesting analysis by Ron at CozyBeeHive. Quite a thorough job. He even used Tracker Video Analysis. However, he didn't use some of the nicer features of Tracker, so I figured I would do this analysis also. Plus, you know I love bikes.…
rallain | February 28, 2010I ride my bike and mostly the wind makes me unhappy. On a very few days the wind is with me on the way to work and then changes so that it is with me again. But most days the wind is fairly constant. So, if the wind is constant then shouldn't everything even out? (Even Stephen).
Assumptions:
Let me start with the assumption that I (a mere mortal) can output at a constant power (but not 57,000 Watts like some people). I will also assume an air resistance force that is proportional to the square of the relative air speed. Here is a diagram.
A couple of quick things to point out. First,…
rallain | July 11, 2009My friend J sent me a link to this gyrobike (http://www.thegyrobike.com/index.php). From what I can tell, it's a flywheel that you put in the front wheel of a bike. The site claims that this will help kids learn how to ride a bike.
So, what do I think? Clearly, this is a real product, but I am not so sure how effective it would be. As I mentioned in a previous post, it's not really about angular momentum that prevents you from falling over. Well, actually I didn't really say that. I referred to an excellent article on the physics of bicycles, David E. H. Jones and published in Physics…
rallain | June 13, 2009Our German friends let us borrow their son's bike after he got too big for it. I guess it will still be called a "bike" because it has two wheels.
See. No pedals. We don't need no stinkin pedals. Really, this is a great way for kids to learn how to ride. They just start off kind of walking while sitting on it. As they go faster, they kind of get the hang of how to not fall over. As I have said before, this is counter intuitive - if you are falling to the right, turn to the right.
I don't know if you can get a bike like this in the U.S., maybe you just need to find a German friend. If…
rallain | December 2, 2008For many people, it is the time of the year to put the bikes away. I live in Louisiana, so now is the time to get the bikes out (too hot in the summer). Learning to ride a bike is a curious thing. Most parents use training wheels to get kids started. I do not think this is the best strategy. In this post, I will focus on teaching bike riding skillz. If you are looking for the physics of bike riding, there are some good links:
David Jones - "The stability of the bicycle" (pdf)This is a great article. The key aspect is that this guy modified a bike in unique ways to see if it was still "…