Reverse Rotating Brake Rotors

[zadok]

Wow this looks like a breakthrough concept:

Reverse rotating brake rotors
Monday February 20, 2006 at 10:39:30 AM by Netrider

If inventor Robby Kasten receives his patent pending design for reverse rotating brake rotors, it could dramatically change the landscape of bike design and riding performance for all of us.

Gyroscopic forces, stability, and resistance to bike lean is what it's all about. Reading through the US patent application and the inventors website, it all sounds feasible and on the level too - if you reverse rotate rotors in relation to the wheel, you cancel the gyroscopic precession, giving you the ability to change lean angles easily.

Imagine a 1000cc superbike that turns easier at speed than a 125 Grand Prix bike! With counter rotating brake rotors, steering effort can be the same at 20 km/h as it is at 200 km/h, while eliminating the possibility of tank slap. Braking feel will also be improved and braking effort required by the rider will be reduced. This new technology is in the last stages of prototype development and is set for testing next month (March '06)

"This is an exciting time for us," said Kasten. "Soon, for the first time ever, we will be riding a motorcycle that changes lean angle almost effortlessly, regardless of speed. The system is very stock-looking, which was intentional. It will be bizarre enough when people see the rotor spin backwards."

Solid Design Solutions, of Florida USA, was hired for development of the first fully functional prototype, and has done a superb job in meeting all of the goals set by Robby. The services of Eagle Machine, who develop parts for land speed record holders, have also been enlisted in the project.

When a motorcycle is leaned to one side in order to turn, the gyroscopic force of the front wheel resists the directional change. It is relative to the speed the wheel is travelling at. In order for a rider to lean the bike over for a turn, s/he must overcome the gyroscopic force of the wheels with an amount of torque equal to the amount of torque generated by the wheels.

By cancelling out these gyroscopic forces of the wheel with a counter rotating disc rotor, the inventor claims leaning in a bike will be effortless at all speeds, thus dramatically increasing rider safety and fatigue.

Websites:
Inventors information
US Patent application

Thanks to: http://www.netrider.net.au/?page=new...a4ef34f4c07280

[bluninja]

Wow, this will start a whole new debate about countersteering...if gyroscopic precession is removed then the only thing turning the bike must be camber thrust from the tyre profiles.

Also if it cancels the gyroscopic forces on the wheels then the only gyroscopic stabiliser would be the crankshaft and flywheel.

[Motu]

Have they ridden the thing yet? Could be a laugh.It's going to take some power to counter rotate the rotors,and feed the braking forces back through what ever mechanism they use...

[Devil]

Have they ridden the thing yet? Could be a laugh.It's going to take some power to counter rotate the rotors,and feed the braking forces back through what ever mechanism they use...

All I can see in my head is some kind of gearbox, but shite, that thing would take a hammering.

[WRT]

Ok couple of things that spring to mind - one is that we use those gyroscopic forces to STAY UPRIGHT. On the flip side, there is more mass in the spokes/rim/tyre than the rotors, so I cant see it cancelling all the forces.

Also, in keeping with what Devil mentioned, the only way I can think to do it (but then again, I'm no "inventor") is using a gear mounted on the forks to spin the discs backwards. I cant see how this would fail to add to the unsprung weight, which is not really a good thing, and as Motu mentioned, its going to cause more resistance for spinning the wheel.

Also, I can only see this having a noticable impact at higher speeds. I guess we will just have to wait and see once they have a working system up and running.

[Mental Trousers]

All I can see in my head is some kind of gearbox, but shite, that thing would take a hammering.

I'll say.

Sounds a dodgy to me. It's very rare for a new technology to be revolutionary when it comes to motorbikes. Even funny front ends like the Bimota Tesi, BMW Telelever etc have been around for donkeys years, they just haven't been properly refined for road use until recently.

This, however, I've never ever heard of. As far as I'm aware counter rotating something only cancels torque forces out, eg counter rotating helicopter blades which mean a tail rotor isn't needed.

Anyone got a physics degree??

[dhunt]

Ok couple of things that spring to mind - one is that we use those gyroscopic forces to STAY UPRIGHT. On the flip side, there is more mass in the spokes/rim/tyre than the rotors, so I cant see it cancelling all the forces.

According to the website this is how they get round it

#3 Braking feel is improved and braking effort reduced due to a dynamic
increase in the swept area of the braking surface. This is because the
rotors are spun faster in reverse in order to cancel the gyroscopic force of the wheel and tire.

It certainly sounds interesting enough I guess we'll see in a few years if it takes off.

[NordieBoy]

Ummm...
See it rotating backwards?
Has anyone looked at their rotors whilst riding recently?
Difficult isn't it.

------------------------
A motorcycle wheel assembly comprising a brake hub rotatably mounted to a wheel axel. A brake disc is affixed to the brake hub rotating with the brake hub. A tire hub is rotatably carried by the brake hub carrying a tire for contacting a road surface to rotate the tire hub. A transfer gear is disposed between the tire hub and the brake hub for interconnecting the brake hub and tire hub. A center gear is carried by the brake hub for engaging the transfer gear, and a ring gear is carried by the tire hub for engaging the transfer gear so that rotation of the tire hub causes the transfer gear to counter-rotate the brake hub. Accordingly, counter-rotation of the brake disc carried by the brake hub creates a counter-rotational gyroscopic force that cancels out the gyroscopic force created by rotation of the motorcycle tire and tire hub.
------------------------

How big is this sucker?

[Darryboy]

Ok couple of things that spring to mind - one is that we use those gyroscopic forces to STAY UPRIGHT.

Exactly what I was thinking. I'm going to be very interested when more details surface.

[T.W.R]

interesting concept indeed, wasn't there a european outfit who had something similar for cars last year ? i'm sure it was displayed on one of the technology programs from germany mid-year sometime.
phenominal braking ability but rather complicated in design.

[k14]

Anyone got a physics degree??

yep thats me, fucked if i know if they cancel out though. am i supposed to remember the stuff i learnt or something?

Rotational inertia acts at a right angle to the axis of rotation (right hand rule) so if you have two bodies rotating in the opposite direction i would have though the forces are antiparallel and thus cancel each other out. I doubt one disc would have enough inertia to be able to cancel out that of a wheel, it would have to have a fairly large diameter to even get close. This is just my flawed understanding of mechanics though, never really got to grips with rotational mechanics.

[SimJen]

We'll have to see how it goes, they are testing at Daytona shortly.
Can't see it really taking off, motogp can handle 200+mph with no probs.
Who cares if it makes it a little easier to turn, the additional weight and possible failure points (locked wheels when gear system spits the dummy) more than likely outweighs the advantages.
Website doesn't look exactly professional either....makes you wonder.

[bugjuice]

yeah, i can't really see how it works..
you'd have to have more balance at low speed than every before. If the effect of doing 200kph is like turning at 20kph, then what's riding at 50kph going to be like? Standing still? I can hold my balance at the lights for may be 30 seconds if I do it right (which isn't often), but then my foot has to come down.. Fuck me am I doing that at 100kph

[onearmedbandit]

30 seconds balancing still? Fuck me, give that man a medal. I thought I had good balance being able to sit stationary in nuetral for about 5-8 seconds. 30 seconds would be an eternity.

[bugjuice]

it's not often I can do it, but if you roll up gently, then use the back brake to stop, it's often the best way to hold it. Then just slowly shift your weight to counter the bike. Or you can do it standing up..

I used to mountain bike a lot, so probably got good then.. motorbikes are just a shit load heavier