[sportbike_pilot]

The only problem is that Keith Code, at least as quoted here, is not exactly correct about this.

In order to steer a bike it must lean. The countersteer is merely the most efficient way to initiate lean.

The sequence of events works something like this for most bikes:

- Countersteer rake and trail combine to steer the bike out from underneath its center of mass (gyroscopic effect has litte to do with this phase)

- As the bike leans a gravitational torque causes the "roll motion" of the bike to accelerate since the bike has a pretty large moment of inertia about it's roll axis the change in angular momentum causes the front wheel to precess in the direction of the intended turn

- this precession causes the front wheel to swing back in the direction of the intented turn and stops the roll of the bike towards the ground.

- the turn is executed.

There are numerous factors that muddy up this general scenario but that's the gist of it. I would note that there is a fair amount of argument even among physicists about the finer points of this, but not about the basics.

Even Tony Foale agrees that this is basically correct which is why I imagine that his seminars recently with Keith must have been interesting.

-sbp

 

[44890]

In my world (which usually bears no resemblance to the real world) I think of turning as intentionally making the bike fall over.

Countersteering is what makes the bike fall in the correct direction. However, my bike fell over so well a few months ago that I am currently bike-less, so what do I know.

 

[34763]

Great comments (those that I understood). As with most debates, I suspect the reality about steering is somewhere in between two opposing viewpoints. Those who focus solely on countersteering avoid the benefits of "hanging off" relative to lowered center of gravity, reduced lean angle, steering the rear wheel, etc. Those who swear by body position seem to discount the fact that their movement is allowing for better (quicker, lighter, more controlled, whatever) countersteering. So if countersteering is all about the efficiency of turning / leaning a bike, it seems that body position is about efficiently managing the inputs and outputs of that process. Doing one without the other is incomplete.

 

[Vlad]

sbp:



I looked at your explanation, and it works for me. I think that the confusion exists because Code is trying to prove that "body english," aka the rider's leaning, isn't what turns the bike. It's countersteering (as in your explanation) that does the trick. We, as riders, lean with the bike. I'm one of the strange people in the world who has practiced swerving, and I don't lean to start anything, I just keep up with the bike. Once in the corner, then your CG can affect the bike's lean angle, but changing direction is dependant on countersteering.



Just my two Euros.



FC

 

[15311]

Well, I can steer my motorcycle and my bicycle without my hands on the bars. However this is only possible because the forks arent welded solid.

It happens because I use body language to initiate movement of the headstock, and normal motorcycle physics takes over from there. It's not that hard, but I wouldnt want to try tight corners.

It's not as accurate and reliable as turning the bars, obviously, but on one outback stretch of road, I once did 40km without touching the bars - gentle curves and all.

I do get that Code's point is to illustrate to riders how important countersteering is, and how that knowledge can make them faster, safer riders.

 

[seruzawa]

Turn... schmurn. I wanna know why KPile's 205 MPH thread got pulled. We had a real flamefest in the making there!

 

[jungkvist]

Whazzup?

Yeah, whazzup wit-at!

I put up a lame post, 'cause I came in second, but I was figuring on a blood bath, later...with K-speare doing his, "Once more into the breach," (of reality) routine.

 

[sportbike_pilot]

I think that our board may have been compromised this evening. Haven't heard back from Sean yet but we may have a real haymaker in the offing. Hope I am wrong tho.



How are things down in yer neck of the wood? Not much snow up here except up high. You?

 

[jungkvist]

I Ain't Never Rode A Black-Board!

Anything over parking lot speed, I counter steer.

Going into a right-hander…I push my right knee against the tank…I lever the right-side of my butt off the seat…I push the right grip forward…The bike leans…I hang-off, with the inside of my left knee hooked on the left side of the seat…The bike does everything else.

Counter-Steering initiates the turn; all other actions are for keeping the most tread on the road, and my hard-parts unblemished. Leaning, I figure, is the natural result of the physical laws of motion and inertia (which I don’t much care thinking about…while dragging my A$$…probably faster that I should…around a curve).

Hey, I like physics as much as the next guy, but I ain’t never rode a black-board….works for me!

 

[39970]

I'm sure that I'm not the only one to note that counter-steering begins at a threshold speed. Before that threshold the Bike steers intuitively (turn right to go right).



Vector analysis shows that the lean angle will increase with an increase in velocity in a constant radius turn to balance the increased centrifugal force the centripetal force must increase equally. These forces must be in equalibrium for both the tire acting through it's contact patch to maintain the intended track and the bike/rider combo to prevent highside/lowside. When you consider that the actual (acting) center of gravity may pass to a point outside of the contact patch, (along the center of the tire) through air to reach the surface amoung many other variables throughout a Motorcycles chassis it is not surprising that Physicists and other smart people find that there is still plenty of "Art" to the science of handling. IMHO



On the banks of Daytona the bikes can approach 90 degrees of bank relative to the earth and the "g-force" can daze a rider with their helmet slamming off the tank with increased force when hitting bumps.



Little wonder that the Fastest guys I've known when I've asked for "Secrets of Speed" have concured "If you want to go fast work on being smooth, speed will come."

 

[seruzawa]

There's plenty of snow in the Wasatch this year, so far. The resorts opened early.



It's 40 degrees today! Wonderful. So do I go riding? Nah! Gotta change the intake manifold gaskets on the K2500. Dammed red antifreeze eats the gaskets.. grumble grumble. If anyone owns a newer car with that stupid red antifreeze, get the system purged and the old green stuff put in before it wrecks something. GM @$$holes.....

 

[longride]

I don't worry about any of this stuff. I just hang on and hope for the best. Worked so far!

 

[23063]

When I learned to ride a motorbike, I started out just like I rode my bicycle. I'm sure we all started out the same. When you lean in the direction of the turn you put a little pressure on the that side of the bar and over she goes. That worked for the machines and speeds we rode.



The bikes in my day didn't let you steer hard. The tires were skinny and most were ridden until nearly bald. The suspensions were stiff. Steering head bearings often went loose and it wasn't unusual to eventually have a little wobbel in the rear end as well. It was real important to keep up on the mainenance.



I remember when old guys on chopped Harleys were among the fastest riders around. We were new riders and just learning new skills.



It's all changed. Now we talk about steering on the internet!

 

[sarnali]

F#@k, I've got that in my van and my Trumpy, are you talking about the Dexron 111? It's supposed to be silicate free 150k mile all that good stuff.



Is your Blazer an older one? my 2000 Venture uses neoprene O rings on everything I've had apart, maybe it don't work with older 350's with paper gaskets.



It's about 25 outside clear and frosty, it's been high 20's and low 30's and foggy all week which is one of the few conditions I won't ride in if I don't have to. Too much black ice and frozen visors.

 

[sarnali]

I never really think about it either, I just pretty much point the bike in the direction I want to go and keep cranking till it get's there.



I just figured the bike read my mind or something.....

 

[sarnali]

Old school choppers were pretty fast, on mine that's where the money went. As long as you didn't get carried away with the forks and stretched the frame to compensate they handled pretty good. I did run Conti's on a 19" single disc front so that helped. God knows rivited shoes on a rigid frame drum brake didn't do much

 

[longride]

Hey Sarnali, I'm am checking out a deal on a Triumph chop project bike. You know, the REAL Triumphs from Meriden! LOL. Looks to be a 72 5 speed Bonnie engine like I had a long time ago in a 70 frame. Looks a bit rough from what I see so far, but it's cheap and will make a nice budget chopper. Triumps are still under the radar for the Jesse James/OCC crowd. Should be interesting.

 

[32849]

Omigod, physicists argue? Say it ain't so.

I admit, I am stunned. I thought this was all just math. I won't be blaming my next crash on physics. Not if they can't agree. I guess i will be out there looking for some other reasons my bike won't work right.

I have to get back to my dog eared copy of the Dancing Wu Li Masters to see if countersteering is subject to randomness.

If I shine a light through a prism will I be able to dynamite the brakes in turn 2 at Pacific in time to stay on line? That's the question that's been bugging me. So far I'm 0 for 2. But I will keep experimenting for the good of science.

What is the difference between real physics and quantum mechanics. And can a quantum mechanic fix my oil leak?

 

[seruzawa]

All I know is that the red stuff is noted for eating the intake manifold gaskets on the 350 small blocks. Several mechanics have told me to replace the red stuff with the old ethyl glycol antifreeze. Wish I'd known that a few years ago.



I'm sure it doesn't help that the manifold is plastic now. Good old American ingenuity.



Be careful though. If there is any red stuff left it turns to a solid goo when it mixes with the green stuff. I mixed the two in a drip pan as an experiment and did in fact get a yellowish goo as a result. So get the old stuff completely flushed out first.



I'm sure that as soon as I get the manifold done it'll snow again. At least I got my Magna out for a bit this AM before starting on the truck.



Remember: There is no such thing as "idiot proof". There is only "idiot resistant". The ingenuity of idiots knows no bounds.

 

[seruzawa]

A guy I know has a '57 Triumph Thunderbird for sale. It's in pieces. He swears it was running when he bought it and only tore it down to paint it and lost interest. What a deal! it might be a wonderful an experience as that Magna I got cheap.