Reverse Rotating Brake Rotors

[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....

[Darryboy]

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

This could get a little confusing....

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

[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!