New Michelin front tire

[cjmitch]

Reversing the tire direction however, is another matter.

It defies all logic that a tread design specifically engineered to move water from the front center of the contact patch to the rear outside will perform that function as adequately when rotating in the opposite direction.

The reason that you should reverse the PA is that there are different shear forces on a rear tire than on a front tire...
Let me explain...

The time when its most critical for a REAR tire to have good adhesion is when the tire is starting off, IE you hit the throttle and take off.

Now picture the tire from the side with that rotational force being applied, the tire will compress slightly at the front (at the point of contact with the ground "contact patch"), now if the rain dispersion groves are orientated as they are on the FRONT tire (ie pushing water foreward, and to the sides), the as the tire "scrunches" it will close off those channels, and to a degree give you a smooth tire (ie a racing slick = hydroplaining, not good:no:.)

You can see this effect when you watch a top fuel, or nascar racer hit the throttle, notic how the tire winkles at the bottom.

NOTE: rain tires are not designed to push water out of the back. they are designed to ush it to the sides, and slightly foreawrd of the vertical center axis. NOT THE BACK, WHY, because once a section of the tire reaches the bottom of the vertical axis, it is then starting to rise from the ground, is no need to remove anything

NOW look at the other side of that contact patch, where the tire is comming OFF the ground in the back. That area is being STRETCHED, so it would make more sense that the treads would be reversed, so that the tire would PUSH the water out of the back of the tire, where these water chanels are being opened up

So now you take that tire and put it in the front, you must reverse the tire rotation to get the correct orientation of the rain groves / tread

Now you may ask why dosen't this happen to the front? Well a front tire (on a MC) is basicaly free wheeling. There are no rotational forces being exerted on the tire BY THE BIKE, it not a drive wheel.
so that "scruncehd" contact patch does not exist, and the tire is free to push the water out of the way via the front/sides.

This is how a Michelin tire rep explained it to me

 

[cjmitch]

deleted

 

[JJTRIKER]

I want to thank you for the explanation i didnt know. I just do what i'm told to do. Now i have a couple of x's that will not agree with that but thats another story lol

thanks

 

[Gorilla]

It does make sense, but I need to give it some more thought.

 

[cjmitch]

NOW look at the other side of that contact patch, where the tire is comming OFF the ground in the back. That area is being STRETCHED, so it would make more sense that the treads would be reversed, so that the tire would PUSH the water out of the back of the tire, where these water chanels are being opened up

I made an error on the above statement... it shoud be as follows
NOW look at the other side of that contact patch, where the tire is comming OFF the ground in the back. That area is being STRETCHED, so it would make more sense that the treads would be reversed, so that the tire would Let the water just flow out of the back of the tire, where these water chanels are being opened up

Thats what I get for trying to "think" as I type

 

[JJTRIKER]

HERE I WHAT MY TIRE LOOKS LIKE AFTER 12K