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=news&action=fullnews&showcomments=1&id=250&PHPSESSID=3d456a44e1e4161baaa4ef34f4c07280

[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?:done:

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

[RantyDave]

Nope. Won't work.

Get a gyroscope and spin it. It stands upright. Spin it the other way. It stands upright. The gyroscopic effect stops it from falling over. It's not like you can get a negative gyroscopic effect ... spinning it backwards doesn't make it fall over faster.

I'll also join the doubters about putting all the braking forces through a gearbox before it gets to the front wheel. It'll be fun when you jump on the anchors to avoid some arsehole backing out of their drive without looking - and promptly snap a gear.

Dave

[TygerTung]

I would have thought that heavier steering at high speeds would be a good thing, stop you chucking the bike into the corners REALLY fast, and then overcoming the tires or highsiding it whatever.

[riffer]

Would you still counter-steer, or counter-counter-steer?

This could get a little confusing.... :gob:

[Darryboy]

Would you still counter-steer, or counter-counter-steer?

This could get a little confusing.... :gob:


I got an 8 in 6th form physics but I'll still have a guess that you'll still counter steer as (the way I see it) counter steering is more to do with centrifugal force as opposed to gyroscopic (although gyroscopic forces most certainly do effect the balance throughout the manoeuvre).

Upon rethinking I am quite sure I deserved the 8 but I will leave this post intact so people can laugh at my failure to comprehend... uh... things.

[Motu]

Pays not to think too hard about it...

If the rotors are geared up to make them spin faster - does this gear them down for braking with reverse input? I can only see the gearboxes having to be made excessivly strong to cope with braking forces.

[RantyDave]

counter steering is more to do with centrifugal force as opposed to gyroscopic
Theyre kinda the same thing. But ... counter steering (as best I can tell) works thus:

* The front wheel goes where you point the handlebars.
* The real wheel follows the front.
* The vertical centre of gravity of a motorbike+rider is about half way up.
* In the absence of a pivoting point an object will rotate around it's centre of gravity.

Therefore the process with countersteering is:

1, Turn handlebar right.
2, Front wheel starts to go right.
3, Back wheel starts to go right.
4, Motorbike pivots about it's centre of gravity, causing it it lean left.
5, Nice roundy tyres start providing a force at a right angle to their centreline and left because they're leaning.
6, Bike accelerates "inwards" - hence around the corner. Left.

Easy. Possibly wrong, but it sounds convincing, eh?

Dave

[Paul in NZ]

Pfft!

Hes wasting his time, this whole disc thing is a passing fad! It, along with electric starts and suspension will soon be a thing of the past! Retro is king man!

[Nutter34]

I'm more curious about it stopping tankslappers....
Surely, if you have no gyroscopic effect, what stops the wheel from 'slapping', since you've lost the inherent stability. Or is that part of rake/trail setup? Would the geometry then have to be changed to compensate?

[Jamezo]

Sounds just fine on the surface to me.

I initially had some concerns that if gears were used to change the ratio of angular velocity between the wheel and rotors, then because of the exponential relationship between angular velocity and rotational energy, the negating effect would not be even along the entire velocity range (and might even run into the negative!)

But then I realised it was the angular momentum which was important in this scenario, which has a linear relationship with angular velocity. So it shouldn't make your bike steer backwards. :spudflip:

We also need to remember that angular momentum does not have to be entirely negated, perhaps just reduced to a comfortable (?) level.


And I'm still not sure, who has The Word on bike steering, I always assumed it was gyroscopic precession, but I've been hearing stuff here and there about tyre reaction forces. I am teh confuzzled!

[myvice]

And not forgetting the new(ish) 2WD that we have now, and ABS linked breaks, and the new goldwing is an auto, and airbag jackets, and on and on...
There is a lot to be said for a simple, everyday, bike with a single cylinder, a carb and a kick start...
Not that I have one, but still...
Would like to pull it apart to see how it works tho...

[GSVR]

Cool concept and when I read it I wondered if anyones ever put power steering on a bike. (no tank slappers and light steering)

Motorbike designers are generally a few years behind car designers.

Sukhoi's aerobatic planes have a huge prop that rotates the reverse direction to the engine. I always thought this was to lessen the torque rolling effect but it should also lessen the gyroscopic precession and make the tail control surfaces more effective.


Heres an explaination of precession http://www.gyroscopes.org/behaviour.asp

[WINJA]

the crank has more effect on turning in speed than the wheels or brake rotors , the wheels and brakes on the 600s and thousands are usually quite the same , and even when you compare an older 600 with heavier components its still turns faster than a later model 1000 with lighter wheel components , most of it i think is down to crank weight, thats a fair chunk of steel doing 10,000rpm

[SixPackBack]

the crank has more effect on turning in speed than the wheels or brake rotors , the wheels and brakes on the 600s and thousands are usually quite the same , and even when you compare an older 600 with heavier components its still turns faster than a later model 1000 with lighter wheel components , most of it i think is down to crank weight, thats a fair chunk of steel doing 10,000rpm

So by deduction we need counter rotating crankshafts to nullify the negative reality inversion of the central diode resistor thus making a 1000 turn like a wheel chair with Steven Hawkins mid mounted rooting his nurse up the poopy.
Sounds good:cool:

[riffer]

the crank has more effect on turning in speed than the wheels or brake rotors , the wheels and brakes on the 600s and thousands are usually quite the same , and even when you compare an older 600 with heavier components its still turns faster than a later model 1000 with lighter wheel components , most of it i think is down to crank weight, thats a fair chunk of steel doing 10,000rpm

Still confused. How does a Moto Guzzi go around corners then? Or a BMW twin?

[cowpoos]

the crank has more effect on turning in speed than the wheels or brake rotors , the wheels and brakes on the 600s and thousands are usually quite the same , and even when you compare an older 600 with heavier components its still turns faster than a later model 1000 with lighter wheel components , most of it i think is down to crank weight, thats a fair chunk of steel doing 10,000rpm

I agree totally with WINJA... the spining forces of the engine have a awesome affect on your bike ability to turn at high speed.... its also a givin that wheels and disc rotors make a difference too...thinner wheels make a difference.... so do smaller diameter wheels....as the weight is more inbound and requires more reveloutions to make the same gyroscopic effect as a larger diameter wheel...so if we look at the rotors as a smaller diameter wheel....they will have to be gear to a large degree to counter the gyroscopic effect...and then it will multipliy the forces need by the braking system to stop...and multipling the braking forces will reduce feel....and another down side is the exra unsprung weight involved with the gearing system will reduce your suspensions ability to work aswell...

a better system would be to mount a inline four engine north south in the frame and have two banks driving a crank shaft one direction and two driving the a crank shaft in another direction....IE:two cranks would be far more benifitial than reverse direction rotors as it will have few down sides...

Ps: WINJA.....whats up with your avatar.....that nude chick made me read far more of your posts than I normally would...and besides ZED liked her!

[WINJA]

a better system would be to mount a inline four engine north south in the frame and have two banks driving a crank shaft one direction and two driving the a crank shaft in another direction....IE:two cranks would be far more benifitial than reverse direction rotors as it will have few down sides...

!
NAH JUST MAKE THE CRANK GO BACKWARDS SO THOSE FORCES ARE PARTLY CANCELLED BY THE WHEELS ,JUST LIKE ROSSIS BIKE , YES ITS LESS PRONE TO WHEELSTANDS

[Motu]

They are turning on the same plane as the rotation of the crank or some such techo talk....kinda like if you had axles and wheels like that too.....In MX there is a trade off between flywheel weight and turning,the heavier flywheel is harder to turn.Same on the flattrack,the XR750 has the advantage of a narrow crank,the old XS Yamaha's were hard to turn because of the wider crank.And Honda turned the CX around to a fore and aft twin.

[NordieBoy]

And I'm still not sure, who has The Word on bike steering, I always assumed it was gyroscopic precession, but I've been hearing stuff here and there about tyre reaction forces. I am teh confuzzled!
Tony Foale speaks The Word on bike steering.

:scooter:

[NordieBoy]

Still confused. How does a Moto Guzzi go around corners then? Or a BMW twin?
They go around corners?

Next you'll be telling me they can wheelie...

:scratch: :wait: :dodge:

[WINJA]

Still confused. How does a Moto Guzzi go around corners then? Or a BMW twin?IS THIS A PT ? IF IT IS YOU SHOULD HAVE INCLUDED THE Y2K IN YOUR QUESTION.
ALL BIKES (IN THEORY WITH THE SAME GROUND CLEARANCE)CAN GET TO THE SAME LEAN ANGLE, HOW FAST THEY GET TO THAT ANGLE IS ANOTHER QUESTION , A 600 CAN GET TO ITS SIDE FASTER THAN A 1000 OF THE SAME SPEC, THIS IS IMPORTANT WHEN THE NEXT EVENT IE THE CORNER THAT IS COMING AT YOU FASTER THAN YOU CAN GET THE BIKE TO LEAN OVER

[WINJA]

In MX there is a trade off between flywheel weight and turning,the heavier flywheel is harder to turn.
WOULD IT BE FAIR TO SAY THEN THAT THE HIGHER YOU CAN HAVE THE HANDLE BARS RELATIVE TO THE CRANK AXIS THE EASIER ITS IS TO TURN IN DUE TO EXTRA LEVERAGE?????? HHMMMMMM

[cowpoos]

NAH JUST MAKE THE CRANK GO BACKWARDS SO THOSE FORCES ARE PARTLY CANCELLED BY THE WHEELS ,JUST LIKE ROSSIS BIKE , YES ITS LESS PRONE TO WHEELSTANDS

well that is true...and probally the simplest thing that could be done

also mounting the engine upside down will make a bike easyier to turn...by moving the crank higher on the bike you reduce the effort required to turn the bike [less bar leverage needed] and I'm surprised some whizzz hasn't done that yet!

[Ixion]

They are turning on the same plane as the rotation of the crank or some such techo talk....kinda like if you had axles and wheels like that too.....In MX there is a trade off between flywheel weight and turning,the heavier flywheel is harder to turn.Same on the flattrack,the XR750 has the advantage of a narrow crank,the old XS Yamaha's were hard to turn because of the wider crank.And Honda turned the CX around to a fore and aft twin.

Yith, it is becos the Guzzi and BMW cranks are effectively very close to the centreline. Remember it is only when you LEAN a rotating mass that gyroscopic forces come into it. An across the frame crank, when you lean the bike you lean the crank. With a fore and aft crank when you lean the bike you simply twist the crank around its own axis. So the crank contributes little gyroscopy, either way.

[riffer]

Great answers guys. Rep to you all.

[T.I.E]

question, when the discussion of crank came into saying that if an engine runs at 10 revs it's harder to turn a corner? due to cranks size eg 1000's ahave bigger cranks the 600's? so if it's in first gear and the engines screaming i'm fucked and ill end up going straight ahead? even doing 70kph? and change into 2nd and revs drop so turning a piss of cake?

and with a counter rotating rotars, i'm interested if it would decrease the cyn-tri-fiya-cal oh shit the force, or would it increse it? the force maybe moving in the opposite direction but it is all based on a single spinning point with the same rotation. just a different direction.

oh my head hurts.

[Pixie]

While thinking about the Gnome-Rhone rotary radial aircraft engine.(the crank is stationary and the cylinders rotate)
I thought it would be good to have the calipers attached to the wheel and the disc fixed to the forks.
That's my silly idea for today.

[WINJA]

question, when the discussion of crank came into saying that if an engine runs at 10 revs it's harder to turn a corner? due to cranks size eg 1000's ahave bigger cranks the 600's? so if it's in first gear and the engines screaming i'm fucked and ill end up going straight ahead? even doing 70kph? and change into 2nd and revs drop so turning a piss of cake?

and with a counter rotating rotars, i'm interested if it would decrease the cyn-tri-fiya-cal oh shit the force, or would it increse it? the force maybe moving in the opposite direction but it is all based on a single spinning point with the same rotation. just a different direction.

oh my head hurts.
YOU WONT GO STRAIGHT AHEAD , BUT YOU WILL BACK OFF THE THROTTLE AND INCREASE THE TIME IT TAKES TO GET TO THE CORNER AS THE 1000 TAKES MORE TIME TO GET ONTO ITS SIDE.
EG ME AND ANOTHER HOON ARE ON OUR WAY TO PIHA IM ON MY GIXXER1000 WITH THE SAME GEOMETRY AND SAME WHEEL AND DISC ROTATING MASS AS HIS GIXXER 600 .GET TO THE FIRST LEFT HAND CORNER AND WE BOTH LEAN IN AND MAKE THE CORNER AT THE SAME SPEED , BUT IF TTHE NEXT CORNER IS A RIGHT AND THE TIME IT TAKES TO GET TO THAT CORNER IS SHORTER THAN THE TIME IT TAKES TO GET THE 1000 ONTO ITS RIGHT SIDE I WILL HAVE TO BACK OFF AND INCREASE THE TIME IT TAKES ME TO GET TO THE CORNER SO I DONT RUN WIDE, MEANWHILE THE FLICKABLE 600 HAS MAINTAINED ITS SPEED AND ALREADY GOT ONTO ITS SIDE READY FOR THE CORNER, AND HAS THEN GAPPED ME BY A FRACTION OF A SECOND, THROW A THIRD CORNER INTO IT AND THE GAP WILL BE GREATER

[Ixion]

While thinking about the Gnome-Rhone rotary radial aircraft engine.(the crank is stationary and the cylinders rotate)
I thought it would be good to have the calipers attached to the wheel and the disc fixed to the forks.
That's my silly idea for today.
Somebody did that. One problem is that the disc will have a heat gradient across it, cos the front will get more cooling than the rear, which may lead to distortion. Also be rather hard to arrange for the hydraulics .

[Ixion]

Mind you, some of the difference between the hypothetical 1000 and 600 may be due to engine width - more weight outboard in the bigger motor. The height of the CoM would come into it , too. And the bigger motor must have either bigger bore (wider) or longer stroke (higher) . I think.

[T.I.E]

YOU WONT GO STRAIGHT AHEAD , BUT YOU WILL BACK OFF THE THROTTLE AND INCREASE THE TIME IT TAKES TO GET TO THE CORNER AS THE 1000 TAKES MORE TIME TO GET ONTO ITS SIDE....


so is it more the weight of the bike due to it enertia or kenetic energy as it wants to go straight ahead as opposed to the crank, limiting it's turning ability?

[WINJA]

Mind you, some of the difference between the hypothetical 1000 and 600 may be due to engine width - more weight outboard in the bigger motor. The height of the CoM would come into it , too. And the bigger motor must have either bigger bore (wider) or longer stroke (higher) . I think.
WIDTH DONT MATTER THAT MUCH , ITS ABOUT 1". THEY TEND TO RUN OUT OF RUBBER B4 MUCH ELSE TOUCHES DOWN , UNLIKE THE ZX9C1/C2 , LHS PICKS UP ALTERNATOR AND SPITS YOU OFF , RIGHT PICKS UP MUFFLER AND LINK PIPE

[WINJA]

so is it more the weight of the bike due to it enertia or kenetic energy as it wants to go straight ahead as opposed to the crank, limiting it's turning ability?
NO MY K3 WAS LIGHTER THAN THE 600 IN QUESTION . BUT THE CRANK IS MUCH HEAVIER , ITS THE ONLY THING THAT WAS HEAVIER.

[Ixion]

No, the rotating masses (various) resist being tilted - thats the gyroscope effect . When you do tilt them they help make the bike go in a circle , but it takes force to do it. Physics professors used to demonstrate with a bicycle wheel on a pole. Hold it over your head , set the wheel spinning, and then try to tilt it. It takes a hell of a force . The more the rotating masses (the heavier they are , or the faster the are rotating) the harder it is to tilt the mass across its axis (side to side). So the more force it needs to bring the bike (and its masses) back upright, and then over to the other side. It will still DO it OK, but it takes more effort (everything else being equal), and thus more time. So it's slower.

EDIT - That was answering Mr T.I.E not Mr WINJA

[T.I.E]

NO MY K3 WAS LIGHTER THAN THE 600 IN QUESTION . BUT THE CRANK IS MUCH HEAVIER , ITS THE ONLY THING THAT WAS HEAVIER.

so the bigger/heavier the crank along with its revolutions, is a bigger hinderence than the weight of a bike, when cornering?

[WINJA]

so the bigger/heavier the crank along with its revolutions, is a bigger hinderence than the weight of a bike, when cornering?
DEPENDING ON THE CORNERS .
I STILL PREFER A 1000 , CAUSE EVEN IF YOU FUCK UP THE CORNERS YOU CAN MAKE IT UP ON THE STRAIGHT, YOU CAN ALSO CORNER DIFFERENT ON THE 1000 STAND IT UP QUICK AND OPEN IT UP , EXCEPT IF THE NEXT CORNER IS TO CLOSE.
PS IM NOT KEITH CODE AND DONT HAVE ALL THE ANSWERS , IM JUST A HOON WHOS BEEN THRASHING PERFORMANCE BIKES FOR OVER 20 YEARS.

[T.I.E]

the crank has more effect on turning in speed than the wheels or brake rotors ,

this statement just confused me. i would have thought at speed the size or weight of the bike would have been a bigger hinderence than it's crank, and at speed the energy or force from a bikes wheels would have been huge.

[T.I.E]

i must admit i prefer a 1000 over a smaller machine or lighter bike. i find it flows more in corners. although if you screw it up, it's not as quick to get out of trouble. but it keeps a steadier and smoother line.

[WINJA]

this statement just confused me. i would have thought at speed the size or weight of the bike would have been a bigger hinderence than it's crank, and at speed the energy or force from a bikes wheels would have been huge.GENERALLY THE ONLY DIFFERENCE IN WHEELS FOR TOP TIER BIKES ACROSS MANUFACTURERS IS 1/2 AN INCH ON THE BACK WHEEL 6" OR 5 1/2", 180 OR 190 . MOST FRONT TYRES ARE 120

[Ixion]

this statement just confused me. i would have thought at speed the size or weight of the bike would have been a bigger hinderence than it's crank, and at speed the energy or force from a bikes wheels would have been huge.

Well, it's all relative. A difference in crank weight may not make up for the difference between a bike weight of , say, 165kg and , say, 300kg !. But sprotsbikes tend to be much of a muchness for weight, you aren't going to get one at 300kg. And the wheels are significant, but once again (a) they're narrow - it's not just weight , it's weight and how much you tilt it (how far the weight is stuck outboard) - one reason why singles are more flickable than fours ; and (b) the wheels tend to be much the same from one sprotsbike to another. Mr WINJA is comparing two very similar beasts .

[WINJA]

to make it simple .
buy 2 gsxr600s , pullthe motor out of one and put a 1000cc in its place , add ballast to the 600 to make it weigh the same as the 600 with the 1000 motor.
the one with the 600 motor in will turn faster in general

[T.I.E]

to make it simple .
buy 2 gsxr600s , pullthe motor out of one and put a 1000cc in its place , add ballast to the 600 to make it weigh the same as the 600 with the 1000 motor.
the one with the 600 motor in will turn faster in general


absolutely agree, i just confused when you said a crank has more of a hinderence than a bikes cyyntryfiicialll (oh boy, use the force luke) force at the wheels whilst at speed when it corners.

but yeah everything else makes sense.

[T.I.E]

[QUOTE=WINJA]the crank has more effect on turning in speed than the wheels or brake rotors ,QUOTE]

i would have thought if you could lose the force thingee from the wheels, that would be a much bigger advantage than anything the crank would produce.

[oldrider]

New thoughts new ideas generate such a lot of excitement and discussion.
I like it and await more information. :banana: Healthy KB chatter. Cheers John

[notme]

Will the prototype run on specially treated water as well? :killingme

[bluninja]

Will the prototype run on specially treated water as well? :killingme

Perhaps it will ride on specially treated water!

[oldrider]

That guy went the way most people expected. Oblivion! April fools prank really. :eek5:
I try to remain optimistic. You never know what some bright spark will come up with next. :scratch:
I am a Myers-Briggs "ENTP". I just can't help myself being optimistic. :yeah: Cheers John.

[Mental Trousers]

to make it simple .
buy 2 gsxr600s , pullthe motor out of one and put a 1000cc in its place , add ballast to the 600 to make it weigh the same as the 600 with the 1000 motor.
the one with the 600 motor in will turn faster in general

Easier to just go around a corner in 6th (say at 80kph) and then go around the same corner in 2nd but doing exactly the same speed. Doing it in 2nd would be harder as the engine is doing a lot more revs.

[ManDownUnder]

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

Which raises the q... would that be enough to stay upright on the road?

At what speed would you be able to stay upright? I can balance at approx 4 or 5kph... what if it did cancel that gyro thingy and I couldn't balance till 20 - would I have to run alongside holding it up?

My thoughts is that's it's a crock. It won;t cancel anything. A spinning wheel is stable due to gyroscopic effects... irrespective of which way the wheel is spinning.

One part going one way, and another part going the other way wouldn't affect the over all level of effect. They don't negate each other as they are actually complimentary forces.

*ding* next!

[TygerTung]

It would reduce acceleration and braking as your wheel has a lot more centrical mass, as it has to spin up the brake disc twice as fast now= more centrical mass= more power used to spin it up etc.

[Ixion]

Easier to just go around a corner in 6th (say at 80kph) and then go around the same corner in 2nd but doing exactly the same speed. Doing it in 2nd would be harder as the engine is doing a lot more revs.
Or, familiar territory, it is the reason that opening the throttle and increasing revs coming out of a corner helps to stand the bike up.

[jonbuoy]

Those little disks would have to be spinning bloody fast to counteract all the mass of the tyre and wheel as they weigh a lot less. I'm guessing they would only do it on the front wheel?

I 'spose you would loose the "tail wagging the dog effect" from a tankslapper, i wouldn't think it would stop them from hapening though. I thought they were caused by short wheelbase, sharp steering angle, ripples in the road and a fistfull of throttle

Hope the boffins get there sums right before the poor bastard rides the bike.

[Milky]

My thoughts is that's it's a crock. It won;t cancel anything. A spinning wheel is stable due to gyroscopic effects... irrespective of which way the wheel is spinning.

One part going one way, and another part going the other way wouldn't affect the over all level of effect. They don't negate each other as they are actually complimentary forces.

*ding* next!

That was the first things I thought too... I am not sure on the specifics of the physics involved, but I didn't see any reason why having one wheel rotating backwards should reduce the overall effect. You still have to change the angle of both wheels, and it doesnt take a negative force to tilt a clockwise rotating wheel to the left, a positive force to tilt it right. Hence surely the rotation direction of the wheel has no effect.

There is a little voice reminding me that when I held a wheel and tried this, the wheel wanted to yaw when tilted... Maybe this is the effect that they are looking to exploit?

[zooter]

Dammit you are making me think aloud: Leaning a wheel rotating forwards requires a torque on the axle in the direction of the lean eg anticlockwise "left hand down right hand up". Imagine someone looking at it from the other side seeing a wheel rotating in the opposite direction leaning in the opposite way by virtue of opposite torque ( leans clockwise, left hand up, right down). Now turn the reverse rotating wheel around it's vertical axis so it is the true counterrotating twin of the original, the forces being applied to it ::argh: this is straining my underutilised brain...

turning the imaginary wheel around has reversed the forces and lean direction so the lean direction is the same as the original but the forces are:brick: somebody PLEASE complete this.....

on another tack the gyroscopic tendency of a spinning wheel I recall being something to do wth conservation of angular momentum, being that the twin wheels are counterroating there is zero system angular momentum to conserve so no gyroscopic force:yeah:

But even if they were sucessful all they would acheive is a big bike that handles like a scooter! All good fun but it takes a real man to make one of them fang!

[Milky]

right.

I got a bicycle wheel from downstairs, and if I spin it forwards, then go left hand down, it wants to push my left hand towards me too. The reverse is true if it is spinning backwards - left hand down, and it pulls my left hand away from my body. Hence, the addition of reverse rotating brake rotors means that less effort is required in the bars to change the spin axis angle of the wheel. This will inherently make the bike less stable. Tank slappers will be less voilent when they occur, as the wheel doesn't contribute as much to the severity as before, but they will be easier to initiate as the wheel is less stable as a stand alone item.

Braking should require less torque at the brake rotors due to the gearing. The rotational inertia of the wheel system will increase slightly due to the extra mass required to reverse the disc rotation, as will unsprung mass. As for rider feel and usability, only time will tell I guess

[thehollowmen]

I doubt one disc would have enough inertia

They'll gear it up to have enough inertia

[crash harry]

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

I think it wouldn't be that bad, you'd still have the gyroscopic forces from the rear wheel. It'd be a bit like balancing a unicycle with a front trainer wheel - maybe more like riding a penny-farthing but not quite as dangerous or ridiculous looking...

It's the rear wheel that does most of your steering anyway, the front is only used to get the bike leaned over in the first place. I think if they got the ratios wrong the steering would get horribly light though - like some of the early Jap power steering on cars. There was no feel cos the steering was too light.

It sounds over-complicated and mostly irrelevant to me though - litre bikes fall into corners easily enough these days...

[Milky]

They'll gear it up to have enough inertia

Pedant alert.

Inertia is not a property that depends on speed. The term you are likely looking for is angular momentum - momentum in a circular path