Learning to Ride a Bike
One of my kids is behind in his learning to ride a
bike. There are a couple of problems. First, the bike
is just the right size (it should be way too small to
learn on). The second problem is that training wheels
don't really do much to help you learn to ride a
bike. To assist in his learning process, I modified
his bike in the following way:
Notice the two modifications:
The traditional strategy for learning to ride a bike is to put training wheels on, then one day take them off. This doesn't really help. One of the important skills to learn to ride a bike is balance. When you are riding, if you are falling to the left you turn to the left. Not an obvious action. So, here is my plan - let him practice pushing on this bike with his feet so he can get used to balancing and then put the pedals and seat back on. He is currently proceeded well in his training.
Here is a good summary of the different approaches to teaching kids to ride a bike.
This started me thinking about the physics of riding a bike. I am not going to explore this area, but rather summarize it - there as already been some excellent articles published on this:
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 "rideable". For instance, some claim that it is the angular momentum of the wheels that keeps you up. To test this, he made counter rotating wheels to produce zero angular momentum. This article is old, but still awesome.
J. Fajans - "Steering in bicycles and motorcycles" (pdf) Another good article. This one has much more detail on the stability of 2 wheeled vehicles. Where as the first article included a large experimental component, this one is more theoretical.
Both of these papers were found at Fajans's site - Physics and Bicycling
Here are some summarizing points:
- Removed the pedals
- Removed the seat and put some carpet padding there (effectively making the bike shorter)
The traditional strategy for learning to ride a bike is to put training wheels on, then one day take them off. This doesn't really help. One of the important skills to learn to ride a bike is balance. When you are riding, if you are falling to the left you turn to the left. Not an obvious action. So, here is my plan - let him practice pushing on this bike with his feet so he can get used to balancing and then put the pedals and seat back on. He is currently proceeded well in his training.
Here is a good summary of the different approaches to teaching kids to ride a bike.
This started me thinking about the physics of riding a bike. I am not going to explore this area, but rather summarize it - there as already been some excellent articles published on this:
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 "rideable". For instance, some claim that it is the angular momentum of the wheels that keeps you up. To test this, he made counter rotating wheels to produce zero angular momentum. This article is old, but still awesome.
J. Fajans - "Steering in bicycles and motorcycles" (pdf) Another good article. This one has much more detail on the stability of 2 wheeled vehicles. Where as the first article included a large experimental component, this one is more theoretical.
Both of these papers were found at Fajans's site - Physics and Bicycling
Here are some summarizing points:
- Is a bike stable due to angular momentum of the wheels? No.
- Does the bike have inherent stability properties? Yes. If you let go of a standing bike, it will fall quickly. If you push it and let go, it will take much longer to fall.
- The most important aspect of bike stability is a positive trail. The trail is the distance between the axis of the front wheel and the axis of rotation for the steering fork.
- Can you turn a bike by JUST turning the handlebars? No. If you try this, you will fall.
