sprint_st
Well-known member
Look, I'm not going to try to give a physics lesson here because I am really not qualified, BUT the ratio of weight to inertia???? Come on!!!!! Weight is a force. It is mass under the accelleration of gravity. Inertia is the tendency of a body at rest to remain at rest or a body in motion to remain in motion. The effect of gravity being a constant on two objects of different mass is because the force of gravity as computed by the universal gravitation constant times the mass of object one times the mass of object two divided by the distance squared and is swamped out by the mass of the earth compared to two objects in question and the comparitive distances are extremely short. Feathers only apply when in a vacuum and none of this has anything to do with brakes slowing down a motorcyle. In the grand scheme of things 16lbs of ABS is insignificant in the stopping distance, BUT overall weight IS significant. If anyone wants a demo, lets set up a time and date and meet in Franklin, NC to run NC 28. I'll be on my Sprint ST and you be on whatever year FJR you want. We have the exact same wheel and tire specs and the FJR has a 27hp theoretical advantage. The ST is around 150lbs lighter. Those 600's will probably smoke both of us but anyone who thinks you can stop a significantly heavier bike as fast as a light one you need to try it on the road rather than out of some report.One last post, and I'll keep it short (for me).
Cannon ball/feather analogy shows the ratio of weight to inertia is constant. In braking, weight holds the tyre onto the road, inertia tries to keep the bike moving. Inertia is proportional to weight. More correctly, both weight and inertia depend on mass.
Friction force of tyre to road depends on weight. With the bike on the side stand, try pulling your front wheel round. Hard, no? Now put the bike on the centre stand, pull up on the front of the front wheel. Oh, lookee, it turns (rubbing a little black stuff onto the ground, and possibly a little BS onto your hand). So, the more weight, the more friction force available. Just enough to deal with the extra inertia of that extra weight.
Finally, at least in modern systems, ABS doesn't work by bike deceleration, nor by comparing front to back wheels. It works by looking at the individual wheel's deceleration.
OK, that's me done.