Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

I'm a hardcore cyclist too. If you're bombing down a San Francisco hill at top speed and lock the front tire, no amount of crouching behind your seat is going to leverage it from flipping. The point is physics is physics, monocycle and bicycle follow the same simple kinematic diagram of pivot point x torque vs pivot point x inertia. If you use 100% of your braking ability you'd better be tall and heavy enough to torque it the other way, else the free body diagram rotates.


There's a world of difference between locking up your front wheel and not using the front brake at all. A reasonably skilled cyclist is able to use the front brake effectively without locking it up.


We are in total agreement. I was illustrating my point that a unicycle rider avoids flipping because they never use the full braking power (lock up the wheel). The gyroscope controller won't let you - you can only brake as hard as you can counterforce (throw your entire body weight hard backwards). As soon as the gyroscope senses a change in angle, the P.I.D. motor controller compensates.


The angle of a very steep hill makes it easier to do a front flip, but such steep hills are an exceptional circumstance. Most of the time, experienced cyclists can safety use a great deal of front braking.


Bicycles are not a physics 101 problem. In practice this just doesn't happen. See the links I provided. You can also read more about this in the "Bicycling Science" book.


A unicycle or bicycle flipping is a Physics 101 problem. First you must lock up the wheel if you want to flip, meaning the complications of kinetic friction are irrelevant. There's a center of mass, a contact point, a velocity, and a force. You can make a free body diagram to accurately calculate if you have the speed and CG to rotate forward (flip). Newtonian physics isn't magic. Telling someone to "read a bicycle science book" just sounds like a flippant dismissive insult. You're safe to assume I'm already well studied. This is a conversation, not an insult battle. If you have a point in mind, then bring it to the conversation in plain english to be inspected under the light of day. What juicy morsel is contained in this book of yours - perhaps it will sell people on moving it to the top of their reading list. Until then it's meaningless.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: