Comments on: Reverse Rotating Brake Rotors

By: Robby

Robby — Tue, 21 Feb 2006 23:46:09 +0000

It works. Of course it adds wieght. Yes the rotors will spin faster. Stoppies are a result of wieght transfer and have nothing to do with which direction the brakes rotate. It does not matter where the calipers are located (as long as they grab the rotors). You pull harder on the bars than you think you do even to change lean angle at 40mph. I never heard of any attempt at this before but it is my understanding that they thought it was an anti-dive solution. It has nothing to do with dive. All of the forces are contained in the lower fork just as before. The point is that the gyroscopic precession of the front wheel is canceled out on the same axis with a mass that you must spin anyway. It makes a massive difference and the prototype will prove it.

By: Hangtight

Hangtight — Sat, 18 Feb 2006 13:10:59 +0000

Don’t forget that with the planetary gearing shown it would be possible to stepup (or down) the rotation speed of the disc relative to the wheel. Higher speeds mean lower loads (power = force x distance moved), greater effective swept area and hence smaller pads/ calipers for the same breaking effect. Thermal mass would become an issue. hmm carbon/ carbon brakes on discs that do 10,000 rpm?

By: aaron

aaron — Sat, 18 Feb 2006 04:49:45 +0000

Ian said-
“The bike would rotate around the front axle, but in the opposite direction, and squat at the rear and probably experience a slight lift at the front?”

the bike tries “to stoppie” because the of the stopping force applied to the bikes through the contact patch. the bikes Cg, being higher than the line of force applied at the contact patch, is subjected to a torque, and tries to turn about it’s Cg. the greater the stopping force, or the greater the lever arm, (height of Cg) the more rotation you’ll get.

besides, friction varies with the normal force. if the bike rotated it’s mass towards the rear, you’d get less normal force, therefore less available friction, (”tire stick”) and less braking availablefrom the front wheel. (even at near lockup) not what you’d want from an “improved” braking system. rear wheel braking would improve in this case though…

By: kneeslider

kneeslider — Sat, 18 Feb 2006 00:13:30 +0000

That gearing issue occured to me, too. Since you’re no longer exerting the braking force directly to the wheel but through the gears instead, either you need some gears made out of unobtanium or they’re going to be heavy or weak.

By: C.J. Luke

C.J. Luke — Fri, 17 Feb 2006 23:46:15 +0000

Well, it doesn’t supprise me that there is plenty of “prior art” and they still got a patent. Our patent system is in a ‘really poor state of repair’ right now.

As for the reverse effect on the dynamics of the front end during braking….I hadn’t considered that…but it seems to me that it would only serve to put a ‘reverse flex’ in the fork tubes as the main forces are still going to be the inertia of the bike and rider. The primary force is generated by the friction of the tire on the road trying to asorb the inertia.

The main problem seems to me to be the size of the gears/mechanism that are reversing the rotor. Modern bikes have more ‘horse power’ in the breaks than in the engine…i.e…they can stop faster than they can accelerate. Seems like that would take some beefy gearing.