# "The Physics Problem"

cjdelphi: I'm amazed there's no gyroscope/accelerometer to give warnings to the rider that they've about to hit point of no return...

some kind of buzzer to alert the rider....

Like he really has the time and spare thinking power to pay attention to some sensor. When you are laid over like that at speed you are putting every bit of spare processing power into feeling what is happening in real time, and the time to process some number on a display would only be letting you know why you went down, not that you were nearing the edge. What got this guy in trouble was that he didn't quite read the bike right and was just a hair fast.

A drop of oil/water/spit/snot at just the right spot and the traction picture can change

Assumptions can be: a) The road is not wet. b) Normal sunshine is there making the road a normally hot

atleast such sort of calculation will definitely help, it will not take away rider's judgment completely but will Supplement what he thinks he's doing and coupled with All that Math and Rider's judgment/experience this may wholly be a great riding experience which is also secure upto some extent.

More complete explanation with pictures and diagrams here:

http://www.stevemunden.com/leanangle.html

Here's the formula BUT....

.067 v2/r = tana

the constant 0.067 depends on many difficult to measure things like rider weight/geometry, bike weight/geometry, tire dimensions/u, street surface, how the rider is sitting or hanging off. 0.067 is anything but constant. You can't calculate it, you have to measure the 3 variables first. The maximum lean angle is much easier all you need is u=tana.

0.067 is anything but constant. You can't calculate it, you have to measure the 3 variables first.

sort of empirical determined variables, most important to determine is how the original variables influence "the constant", linear exponential quadratic chaotic etc. If that is determined one can derive formulas and calculate it.

This is sometimes trivial, but often rather complex as the variables you start with and measure may not be the "root" variables but depend on an underlying mechanism. Furthermore the "root" variables may change in time which causes the need to recalculate the "constant" constantly. Rules of thumb and approximations maight become the only workable solutions.

And note that the speed you can take a certain radius turn will be different in a level turn vs a descending or rising turn.

Racers learn the course before trying for maximums. A good rider knows how far he or she can lean and still there is no guarantee of safety. What margin you give is the margin you get. Just because someone has killed a tiger with a stick doesn't mean to approach tigers with sticks.

0.067 is anything but constant.

This Constant is a Constant problem.

Actually the lean angel WITH RESPECT TO GRAVITY, does not depend on the road surface banking angle. I may have mistakenly included a few variables in my list that do not change the constant, but some of them do.

yes I understand the explanation on that page was Really precise. the only thing now holding me back is how can I get the Radius 'I was banking Upon accelerometer to get the tilt & its corresponding Radius by forming a look-up table.

There’s no cheap way to measure tilt. You’d need an expensive Gyro because of the vibration. Accelerometers are useless of course. The only way I can think of to measure radius is predetermined based on the road, or GPS.

And where would you take the angle measure? Bike and rider tilt WRT each other, helmet tilts and turns. I leaned inside of hard turns and lifted the inside leg to let the peg fold up. Helmet always turning, I needed to keep awareness high. What's your tire-patch angle on a high crown road as opposed to a low crown road? I once went into a T at 45 mph on a bike with low center stand and slid a ways on the crown with the back wheel off the ground before getting back on two wheels and continuing along my way. I was already letting off the throttle, the back wheel didn't torque me and it's the front wheel that keeps you up. A little instinct with a lot of practice behind it, just hang in there and such minor events won't end your happy day. My accelerometer and gyros are built-in and pre-wired.

A little instinct with a lot of practice behind it, just hang in there and such minor events won't end your happy day. My accelerometer and gyros are built-in and pre-wired.

perhaps thats the reason such system isn't integrated yet.

Mine are inner ears and kinesio sense I was born with and trained.
Unfortunately they are not calibrated, nor are my eyes and ears, etc.
All are Mk I OEM wetware parts though the eyes have manufacture defects.