Counter Rotating Brakes Vid

[Phil 998]

Originally Posted by banda

Motorcyles don't lean because they are turning, but rather they turn because they are leaning - the tires are narrower in diameter at the edges than they are in the center, causing them to roll in an arc when leaned over - like a styrofoam coffee cup lying on its side. Coning.

I don't agree with this at all Banda. I can very easily ride down the road when there is a strong side wind and go straight as a string while the bike has a lot of lean angle. When I countersteer a bike, if I put effort into one of the bars while the bike is straight up and down, it turns now.

[banda]

Originally Posted by Phil 998

I don't agree with this at all Banda. I can very easily ride down the road when there is a strong side wind and go straight as a string while the bike has a lot of lean angle. When I countersteer a bike, if I put effort into one of the bars while the bike is straight up and down, it turns now.

No one told you you had to take my word for it. I'm repeating David Hough, who is repeating the Wright Brothers. You can believe anything you want to believe.

So the wind is pushing you one way, your tires are pushing you the other, and the fact that you're going in a straight line is proof of what again?

[banda]

Ok. My last words on the subject: Don't take it from me. Read Physics Today from 1970:

http://ist-socrates.berkeley.edu/~fa...onesBikeBW.pdf

[PSk]

After reading the pdf ... thus a bike stays upright due to front wheel geometry, ie. rake and trail ... and the gyroscopic affect has minimal affect on upright stability (makes sense as it is easy to lean a spinning wheel a few degrees but gets progressively harder ...).

We all know though that gyroscopic affect makes a wheel when spun harder to lean horizontal ... so yes it might not provide the stability we think, but it makes it harder to lean and thus corner a bike.

Hence why lighter wheels make a quicker turning bike ... and hence why this counter rotating brake disc might be easier to turn. One thing that does confuse me ... brake discs on most bikes are pretty light and much smaller than the wheel, thus surely they would only cancel out about 1/3rd of the gyroscopic affect of the larger and heavier wheel?

Pete

[cgarrison]

Originally Posted by PSk

One thing that does confuse me ... brake discs on most bikes are pretty light and much smaller than the wheel, thus surely they would only cancel out about 1/3rd of the gyroscopic affect of the larger and heavier wheel?

Pete

I quickly browsed through all the posts, and haven't had time to really consider the issue much, but I believe the answer to your question about the size of the brake rotors is answered by the fact that they spin in reverse at a higher speed than the wheel is spinning, making up for their smaller size.

[AZ Scott]

Motorcycles do NOT lean because of the gyroscopic effect of the wheels.

They lean DESPITE the gyroscopic effect of the wheels.

Banda is 100% correct on this matter, and Kevin Cameron - all due respect - is wrong. Them's the facts.

Tell me...

How does a downhill skier change direction, when he has no gyro effect whatsoever?

How can a 200 pound man riding a 12 pound bicycle with carbon fiber wheels change direction so quickly, yet remain stable at 45 mph?

[Dezmo]

Originally Posted by AZ Scott

Tell me...

How does a downhill skier change direction, when he has no gyro effect whatsoever?

How can a 200 pound man riding a 12 pound bicycle with carbon fiber wheels change direction so quickly, yet remain stable at 45 mph?

apples and oranges......besides who said gyroscopic effect is required to turn anything besides a motorcycle?

And all you guys thinking cameron is wrong is fine, thats your right.

But until I see some proof (and I dont mean 36 year old articles about bicycles ) I will believe what I have found to be the truth

I cant say for certain, but I would wager nobody who has posted on this thread is a physics major....not that you need to be, its pretty easy to understand using what I remember from HS physics (not much)

[Phil 998]

Originally Posted by banda

So the wind is pushing you one way, your tires are pushing you the other, and the fact that you're going in a straight line is proof of what again?

I thought you could follow, this is your quote "Motorcyles don't lean because they are turning, but rather they turn because they are leaning"

My point is, the bike was leaning and not turning, it was on the smaller diameters of the tires and still going straight. I was making a point to discuss this, it was not a personal attack. Worse things have happened than having someone disagree with you.

[banda]

Originally Posted by Phil 998

I thought you could follow, this is your quote "Motorcyles don't lean because they are turning, but rather they turn because they are leaning"

My point is, the bike was leaning and not turning, it was on the smaller diameters of the tires and still going straight. I was making a point to discuss this, it was not a personal attack. Worse things have happened than having someone disagree with you.

You're right. My response was smart assed.

And you're right again. leaning doesn't produce a turn. It produces a turning force. A force which can be counteracted or enhanced by other forces.

I'll try to be more adult next time.

[banda]

Originally Posted by Dezmo

But until I see some proof (and I dont mean 36 year old articles about bicycles ) I will believe what I have found to be the truth

Do physical principles go bad after some amount of time? Is it just a few decades? Maybe that's why we haven't been back to the moon.

Originally Posted by Dezmo

I cant say for certain, but I would wager nobody who has posted on this thread is a physics major....not that you need to be, its pretty easy to understand using what I remember from HS physics (not much)

Does Mechanical Engineering count? Granted, most physicists look down on MEs because they concentrate on statics, dynamics, deformable bodies, and thermodynamics, but those things seem to be better related to motorcycling than quantum mechanics and string theory.

[Just Riding Along]

Ok, so you're just riding along. Your motorcycle "wants" to go straight. You have to overcome that momentum to go around a corner. Exactly the same on a bicycle since all common 2 wheeled vehicles are governed by the same laws (saying different would mean that you believed bicycles existed in some separate dimension, we're not talking Buckaroo Banzai here).


Now let's take the corner and even the ground out of the equation. What's going on in this photo (thanks MXA destops)?

[944Monster]

Originally Posted by Phil 998

I don't agree with this at all Banda. I can very easily ride down the road when there is a strong side wind and go straight as a string while the bike has a lot of lean angle. When I countersteer a bike, if I put effort into one of the bars while the bike is straight up and down, it turns now.

I spent about 2 hours in the most hurrific,for me on a motorcycle,crosswind riding through Indio and Palm Desert Ca. At one point I got a peg down and the force that kept me on track was steering into the wind.
Countering the lean if you will.
The wind was coming from my right and the bars where turned right,I'm sure it was atomatic on my part,to stay on track.

When the gust would let up I would pop upright right now! Then almost counter steer my ass into the wind again.

I heard later the wind was in the 50-70mph range that day!

[Dezmo]

Originally Posted by banda

Do physical principles go bad after some amount of time? Is it just a few decades? Maybe that's why we haven't been back to the moon.

no, but one can hardly compare notes from a 36 year old bicycle and a 180mph superbike....I read the article and found it inconclusive....its impossible to cancel out gyroscopic forces without a equal force in the opposite direction, without somehow having another front wheel spinning backwards in the same area currently occupied by the forward spinning front wheel. This is why counterbalanced engines still vibrate, its physically impossible to make a setup that cancels all the forces out.

[AZ Scott]

Originally Posted by Just Riding Along

Now let's take the corner and even the ground out of the equation. What's going on in this photo (thanks MXA destops)?

This is the "apples and oranges" Dezmo was talking about. In the air, everything changes. When motocrossers get crossed up in the air, that's absolutely the gyro effect at work.

However, it has nothing whatsoever to do with a bike on the ground leaning into a turn. When was the last time you saw a superbike going through a turn upside down (on purpose)?

You can pretend that motorcycles have their own set of physics at work, but the fact is, a 30 year old bicycle and a 180mph superbike do in fact use the same basic principles to go around a corner. Believe it or don't.

[millemille]

Counterbalanced engines viabrate because they operate over a wide rpm range.

There will be an rpm, and multiples thereof, where viabrations do not exist. This is due to the primary balance factor used in the balance calculations - an engine can only be balanced for a set rpm, or multiples thereof (unless an engine, such as ducati 90 degree v twin, has perfect primary balance). Engine manufacturers decide during the R+D process where they believe the engine will spend the majority of time within the rpm range - the primary balance factor will then be derived to balance the engine at some point within the chosen band.

Anyone who believes otherwise is welcome to throw their hat into the ring on how to fit lighter pistons and conrods to a rotax V60 engine and retain primary balance via the two balancer shafts.....

[Just Riding Along]

Originally Posted by AZ Scott

This is the "apples and oranges" Dezmo was talking about. In the air, everything changes. When motocrossers get crossed up in the air, that's absolutely the gyro effect at work.

However, it has nothing whatsoever to do with a bike on the ground leaning into a turn. When was the last time you saw a superbike going through a turn upside down (on purpose)?

You can pretend that motorcycles have their own set of physics at work, but the fact is, a 30 year old bicycle and a 180mph superbike do in fact use the same basic principles to go around a corner. Believe it or don't.

I know the physics is the same, I was trying to condense what happens when you steer down into some simple description and had to give up and post the picture instead (I dont' have the bunny with a pancake on it's head).

The explanation is 10 pages long, and still leaves you scratching your head. At least when you're in the air we don't have to talk about tire slip.

What I really don't know is what we're all arguing about here.
Gyro good or bad?
Turn then lean, or lean then turn?
Backwards spinning brakes cool or junk?

[AZ Scott]

Originally Posted by Just Riding Along

What I really don't know is what we're all arguing about here.
Gyro good or bad?
Turn then lean, or lean then turn?
Backwards spinning brakes cool or junk?

Gyro - Good for stability, BAD for efficient steering.

Lean - then turn.

Backward spinning brakes - Probably a bunch of crap.

[sp2pilot]

The more things change the more they stay the same

Harley Davidson used backwards spinning front brake rotors on its 500 cc GP bikes in the late 1970's


There is currently one on display at the Barber Motorsports Museum in Alabama

[Just Riding Along]

Originally Posted by sp2pilot

The more things change the more they stay the same

Harley Davidson used backwards spinning front brake rotors on its 500 cc GP bikes in the late 1970's


There is currently one on display at the Barber Motorsports Museum in Alabama

Any other un-patented items there? Maybe it's time for me to do some cyber-squatting and make my fortune.

[UnpaintedHuffhines]

the motor has more gyroscopic influence than the rims by far

c1