3dogs
Well-known member
I’ll have to disagree with your BS call on hanging off vs. lean angle. Here why.
In teaching Total Control to the Marines we did a class experiment to show lean angle as it relates to hanging off. Here are the steps we took.
1. With the rider on their bike sitting completely upright in the center of the seat (and not moving at all).
2. I balanced the bike using pushing on the right and left hand grips with one finger (I stood over the front tire).
3. An Inclinometer was placed on the fuel filler cap and zeroed out.
4. The distance from both foot pegs was measured (theoretically they should be the same and if they are slightly different this can be taken into account for later calculations). For this example we’ll use 10 inches for each side.
5. Now the rider hangs off with other students holding the bike. (in Total Control we spend a great deal of time teaching the correct body position for doing this).
6. Step “2” is repeated but this time the rider is leaning one direction (hanging off) and the motorcycle is leaning the other. The inclinometer angle of the bike is read. For this example we’ll use 10 degrees.
7. Step “4” is repeated. The side of the motorcycle that the rider is hanging off is now going to be further from the ground. The side that the bike is leaning towards will be closer to the ground. For this example let’s say the foot peg measurements are 10.5” and 9.5”.
8. The difference between the two foot pegs is the amount of ground clearance that is increased by hanging off—in this case 1 inch. This is also the amount that the lean angle has been reduced.
How much hanging off reduces lean angle is a function of the motorcycle’s weight in relationship to the rider’s weight—heavy rider on a very light bike will equal less lean angle when hanging off.
In the real world suspension does have much to do with scrapping. If the spring rate is to soft the suspension will compress too much in a turn (due to centrifugal force) causing a loss in ground clearance and thus touching down of hard parts. So It’s not just too soft of a spring (or not enough preload) that can cause scrapping but also changing the center of gravity, or not hanging off.
Another Experiment
When teaching motor officers Total Control an experiment was tried to prove that hanging off increased ground clearance. Here are the steps.
1. I placed a GPS on one of the police bikes and set it to record max speed.
2. The officer rode around a 40 foot circle sitting bolt upright in the seat. He started out slowly and gradually increased speed without changing the diameter of his path of travel. He did this until the inside floorboard scrapped. The GPS indicated a max speed of 18 mph.
3. Reset the GPS for max speed and the student rode the circle again—this time hanging off (I had him slide off the seat like he was riding a sport bike)
4. He rode around the circle steadily increasing his speed until the inside floor board scrapped. The GPS recorded a speed of 22 mph.
His suspension was not changed –the only variable was his body position (hanging off). He achieved a higher speed (without scrapping) for the same diameter of circle because he had more ground clearance—proving that hanging off does help prevent scrapping.
I’m finished with my *********---maybe you’d like to add more of your own!
(May be too twitchy for some?) And hanging off does help w/ ground clearance, but ya gotta be able to move around on the bike smoothly while be'in light on the bars.
