​Forces to Turn a Bicycle Wheel


Abstract: A brief description of the exploration.
Subject Author Replies Views Last Message
Halfway Point pasquinit pasquinit 0 27 Nov 29, 2009 by pasquinit pasquinit

Guiding Question

How does the speed of a wheel spinning affect the force needed to turn in?

Hypothesis/Prediction

If the wheel is spinning faster it will be harder to turn, because it will have more energy on one axis, and that will make it harder to make it go off the original axis. If the wheel has a higher mass, it will also be harder to get off axis, because it has more energy spinning on its original axis.

Experimental Procedure

I will take a bike, and put it in a bike stand with the headtube vertical. that way gravity will be elimintaed from the problem, i will also use a bike that has a headset that spins freely so that friction is also largley eliminated. i will spin the wheel at 2 different speeds, and measure the force used to turn the handlebars.

Experiment

In Progress...
This is the contraption that i've created to measure the force needed. eliminaing gravity, by making sure the head tube of the fork is vertical.

bikegyro1.JPGbikegyro2.JPGbikegyro3.JPG
I measure how much force it takes to turn the wheel when it is not spinning, when it is spinning at 1/2 speed, and also when it is spinning as fast as i can make it go. I had no good way to measure how fast the wheel was spinning, so i spun it as fast as i could, and what looked to be 1/2 of that speed. Looking for an accurate way to collect data, a spring scale didn't seem to be very accurate.
While i was starting to collect data, i noticed that if you kept the wheel spinning the same way, but turned the wheel different directions you would get different measurements. So i collected different data for when i pulled the spring scale with, and against the rotation of the wheel. I determined with and against by just seeing which way the bottom of the wheel was spinning.


Data/Analysis

I made some charts in a program called numbers (Apple's version of Excel). I collected data 3 times with the wheel at different angles, so if the headset was a little stuck in one particular spot i could average it, and it would not matter. Below are my tables of data, with the average values at the bottom.


ALL FORCES MEASURED IN NEWTONS.
Screen_shot_2009-12-17_at_8.20.59_PM.png

It wasn't as clear as i would have liked it to be that the heavier wheel and the one spinning faster used more force to turn them, so i decided to make a nice bar graph to make it clearly stand out.

Screen_shot_2009-12-17_at_8.22.31_PM.png

Conclusion

  • I've always wanted to know if the wheels spinning had any influence on how the bike would flip, frontflip or backflip. When I backflip i let the rear wheel spin freely throughout my flip. It may not have a big impact on the bikes ability to flip.
  • These results are important to me because now i know that it will be easier to execute certain tricks on my bike when the wheels are spinning as slow as possible.

Sources

I dont necessarily remember doing any research for this project.

Acknowledgments

I'd like to thanks Mr. Dickson in the industrial arts room for letting me work in his shop, and lending me some random parts to built my experiment with.
I didn't really want a VPI for this project, because I thought it'd be more work than necessary to keep them updated on my project. So Mr. Dickson is the only person who really contributed to my project.

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