Nice article but It's the force that makes the magic happen.

 

Okay guys, here's the answer you've all been dying to hear: It's the shape of our tires. Of course, tires are round or they wouldn't roll, but they also have a rounded profile, unlike car tires, which have straight sidewalls leading into a flat tread area. Motorcycle tires have a rounded tread area.
Take a funnel and lay it on the floor. Give it a little nudge so that it rolls across the floor. Does it roll in a straight line? No, it rolls in a circle because one end is fatter than the other. Now take 2 funnels and attach them together so that the fat ends are mouth to mouth and the 2 skinny ends stick out to the sides. If you stuck a long skinny rod through the middle, like an axle, you could roll this in a straight line. When it's tilted so that the smaller diameter and larger diameter are both in contact with the floor, the larger diameter wants to roll farther for each revolution, therefore the unit rolls in a circle. I'm not sure that my explanation will make sense to every one. If not, feel free to ask questions.

 

ya, i was wrong... I didnt really think about the tires that much, more of rotating force and such. I suppose thats a good answer considering the more you wear off the curve of you tire the harder it is to turn the bike.

 

As Paul Harvey use to coment, now you know the rest of the story. Some of you may not be old enough to remember this. Johnnyh

 

god i just got my first bike like 2 weeks ago and thats what i guessed and i dont know ****. but then again ignorance is bliss, and all the other answers were probably too complicated for me to figure out so i went with the easy one lol.

 

A pointier profile makes quicker turn-in. I use a Michelin "V" competition front which has a more pointed profile and has one of the quickest turn ins ever.

The rounded profile is also why weaving doesn't significantly warm your tires, though people love to do it.

 

Guilty, hahahaha. I know it doesn't significantly warm them, but I do it anyway.

 

That would explain things IF motorcycles had tires of different diameters mounted side-by-side and on the same axle.

If your explanation were correct, you could take any round object and roll it and it would roll in a curved line.

The reason a motorcycle turns is described in the diagram posted earlier in this thread. If you look at the diagram of the rider initiating the turning process, you'll see that he first counter-steers to cause the bike to lean to one side or the other. Once the bike is beginning to lean, the rider will begin turning INTO the turn, opposite of the initial counter-steer. This turning of the handle bars INTO the turn causes the motorcycle to track in a curved line. The bike's lean is merely to counteract the centrifugal force that is trying to push the bike to the outside of the curve and does not, itself, cause the bike to turn. The shape of a motorcycle's tires is NOT what causes the bike to turn when leaned to one side or the other. It is, in fact, friction caused by the front wheel being turned in the direction of the curve that causes the bike to turn.

Don't make it harder than it is, folks. Turning on two wheels is very much like turning on four. You just don't have to lean when on four wheels (so no need for counter-steering).

 

Okay, patches.
Let's conduct a little experiment. We'll have to use your bike though because I'm not about to try this with mine. Get on your bike, go find an entrance or exit ramp, you know the ones I'm talking about, those long circular ones like you find that look like a big clover leaf. Use our nifty counter steering technique to start your turn and after your bike is leaned into the turn I want you to turn the bars gently into the turn. According to your explanation this should tighten the radius of your turn. WRONG!!! Whenever you get out of the hospital after wadding your bike up on the outside of the turn I want you to come back and tell us how that worked out for you.
I hate to be an *** about this but you obviously have no clue what you're talking about. Turning a bike is like turning a car? WTF? You should have checked out the counter steering post that Jules put up where she had the pointer installed on the top triple tree. Never ever does the handlebar turn into the turn. It will come back to a neutral steering position and no farther, at which time the bike will be leaned over and the "different diameter" function will keep the bike turning.
Go take the MSF course, or some other motorcycle riding course before you come into a forum and start spewing bullshyt that could get someone hurt or killed.

 

Not trying to get into a pissing match here, but you can go out to your garage and prove your explanation wrong yourself without even cranking your bike. Go out and lean your bike over a little bit and push it forward without turning the handlebars at all. Which way does it go? Straight line! Imagine that! Push it forward a bit and turn ever so slightly into the direction you are leaning and your bike will turn in that direction. It's really not that hard to understand and if you really, really pay attention when you are turning a nice wide curve on your bike, you'll realize that after you've leaned a bit, you're turning the bars back into the turn. It's just that most of the time, you've not turned the bars enough for you to physically notice.

Your explanation about the funnels will ONLY work if you had two tires of different diameter mounted side-by-side on the same axle with both of them touching the same surface at the same time. It simply does not apply to a single motorcycle tire, at all. None.

There was another thread on here that even had videos about counter-steering and you could clearly see, when the videos were played in slow-mo, that the front wheel turns back into the direction of the turn after the bike had been leaned over sufficiently.

And I have taken the MSF safety course. What the MSF teaches is to "push left, lean left, go left", but look at all of their diagrams and look at all the actual riding videos that have been drawn or recorded to demonstrate the technique and you will see that what I'm saying is correct.

In all seriousness though, I challenge you to go out to your bike and lean it to the side while keeping the bars straight as an arrow and then push it forward. Come back after you've done that and tell me that your bike has turned in a circle with no turning of the bars!