Elliot, Do you have any old school beach cruiser pedals? The ones that have the individual rubber blocks held onto the metal pedal frame with thier own bolt?Elliot wrote:
Next... I think reversed pedals that unscrew themselves, but I need to do some Gainful Employment first.
Elliot wrote:
Drill and tap hex stock? You can buy that in any hardware store -- it is called a barrel nut or coupling nut. About something like maybe four or five times longer than a normal nut.
One pedal falling off will probably stop the bike just fine.
As for left-hand thread, I'm thinking that a crank arm can be cut and welded to swap sides.
Now... I may not be awake yet, or something, but my mind is struggling to comprehend the rotation and unsrewing of pedals. In my mind, it looks like normal pedals would unscrew themselves. Perhaps you could explore that question as a sanity check. My mind is on something else at the moment.
Pedal Threading
Direction
The right pedal has a normal thread, but the left pedal has a left (reverse) thread.
The reason for this is not obvious: The force from bearing friction would, in fact, tend to unscrew pedals threaded in this manner. The fact is, however, that it is not the bearing friction that makes pedals unscrew themselves, but a phenomenon called "precession".
You can demonstrate this to yourself by performing a simple experiment. Hold a pencil loosely in one fist, and move the end of it in a circle. You will see that the pencil, as it rubs against the inside of your fist, rotates in the opposite direction.
Ignorant people outside the bike industry sometimes make the astonishing discovery that the way it has been done for 100 years is "wrong." "Look at these fools, they go to the trouble of using a left thread on one pedal, then the bozos go and put the left thread on the wrong side! Shows that bicycle designers have no idea what they are doing..."
Another popular theory of armchair engineers is that the threads are done this way so that, if the pedal bearing locks up, the pedal will unscrew itself instead of breaking the rider's ankle.
The left threaded left pedal was not the result of armchair theorizing, it was a solution to a real problem: people's left pedals kept unscrewing! I have read that this was invented by the Wright brothers, but I am not sure of this.
Note! The precession effect doesn't substitute for screwing your pedals in good and tight. It is very important to do so. The threads (like virtually all threads on a bicycle) should be lubricated with grease, or at least with oil.
Hmm, how about positioning the crank arms at the same relative position on both sides rather than 180 degrees apart?Elliot wrote:
Shorten one crank arm -- no problem. Good for a "beginner's untamed bike".
But then my brain kicked in... how about different gear ratios? One foot has to pedal faster than the other! The neat way would be a planetary gear set hidden in the center of the crank. But the more realistic way -- fabrication-wise -- would be a sprocket on each side, going to an intermediate shaft. Could hide that with "routine BRC fake fur".
