Tire chop





kjcili

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#1
I'm on my 3rd front tire in 12K. All of them have ended up being chopped. I've had my forks rebuilt cuz they were leaking and i've tried tweaking the adjustments this way and that, but they still chop. I's confused, any1 else run into this.
 

kjcili

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#5
Please:
What is "chopped"
New term for me.
tire chop is an uneven wear across the pattern of the tire. if you run your hand across a new tire it's virtually 'flat'; whereas, a chopped tire will have hi & lo spots, usually caused buy bad shocks, springs, or in the case of a car, struts.
 
#8
My front tires do it too.
The way it was explained to me is in a hard corner, the leading edge bites in an the next edge (next in tread) then bites in.
Picture 10 pencils held in a group with the erasers down.
Now drag that group across a table top. The leading edge of each eraser will wear, and the trailing edge will not wear as much, even if the eraser is in the middle of the group.
If you turn hard, it just happens.
Please pipe in if I am wrong.
 

kjcili

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#9
I can see the theory, but i'm not a knee dragger, so I don't THINK that's it. I do get low sometimes but I didn't think I did it often enough to chop the tire. I'm gonna have to do some more research on the "pencil eraser" to tire theory and see how it plays out.
 
#10
I can see the theory, but i'm not a knee dragger, so I don't THINK that's it. I do get low sometimes but I didn't think I did it often enough to chop the tire. I'm gonna have to do some more research on the "pencil eraser" to tire theory and see how it plays out.
I think it is a function of how hard/soft the front tire is too, and the weight on the tire and air pressure.
Low pressure, heavy weight, soft tire will increase that "chopping"
 
#12
Hey I saved it, here it is:

Motorcycle Tire Wear


CUPPING:
Cupping, which is more accurately described as scalloping (see pictures, but we will use the more common term "cupping" here), is a natural wear pattern on motorcycle tires and it will always follow the tread pattern. It is not a sign that you have bad suspension parts. It merely shows that your tire is indeed gripping the road when you make turns (thank you for that Mr. Tire!). This cupping develops within the side wear bands of a leaned motorcycle. The extreme forces that come in to play when the bike is leaned in a turn are what produce the effect and when the wear becomes sufficient, one will experience vibration and noise when one banks into a turn. Upon examination of the pictures at left of our sample rear Avon, our dusted front VTX Dunlop D256, and the picture of our chalked Dunlop D206 one can see how the cupping follows the tread pattern. The leading edge of the tread does not flex much as it grips the road and the rubber is scuffed off the tire in that area causing a depression. As the tire rotates, the pressure moves to the trailing edge of the tread pattern where the tread flexes more causing less scuffing so less material is ground off the tire. The more complex the tread pattern, the more complex the cupping pattern will be. The softer the compound of the tire, the sooner this cupping will develop. Radial tires are more prone to cupping than are bias ply because the compound of radials is softer. As one can see, the simple tread pattern of the Avon pictured produces a simpler scallop pattern while the more complex VTX D256 Dunlop is somewhat involved, though still easily seen in our photo. Cupping on the Valkyrie Dunlop D206 is very hard to photograph because of the complex tread pattern. Low tire pressure will exacerbate this wear pattern and you will lose many serviceable miles by running low. Improper balance has nothing to do with cupping on a motorcycle tire. Improper balance will merely cause your bike to vibrate within certain specific speed ranges.
The following textual illustration comes from Martin who contributed to this article by E-mail on June 26, 2006:
I was just reading your bit on "cupping" and thought I'd share with you how I describe what's going on. I usually tell people that what's happening is that the individual "blocks" or "islands" of tread are squirming and deforming due to the forces applied to them during cornering and braking. When this deforming takes place, the wear is naturally not evenly distributed across the surface of the tread. (I define a tread block as an area of the tire surface surrounded by a groove.) I next tell people they can demonstrate to themselves what's happening by taking a new pencil with an unused eraser on the end and while holding the pencil perfectly vertical, push down and drag the eraser on a rough surface in one direction. Then I tell them to look at the eraser and note that all the wear is on the leading edge and not evenly distributed across the end surface of the eraser. It seems to make the concept easier for many to understand. Cheers!

Cupping.jpg
 
#13
Are you referring to this? If so, it's cupping caused by the braking and turning stress that deforms the tread and carcass. It is normal on bikes that have been ridden agressively and on heavier bikes like the Busa, FJR and ST1300.

TredCupping.jpg


TredCupping2.jpg
 

wardie

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#14
Has anyone noticed that the cupping usually occurs on the left (clutch handle) side the of tire? This is caused by the crown in the road and the fact that Americans drive on the right side of the road. You wear that side/portion of the tire more. Think about it and it will make sense. You can minimize cupping by running your tires at 42 psi and run dual or triple compound tires the kind where the center section of rubber is harder and as you go to the edge it gets progressly softer. This is just my experience but I put several thousand miles on a year and have had these problems before. Wardie
 
#16
Hmmm quickest and cheapest way to fix this I had similiar issues with mine is buy a complete front forks and yoke set usually comes with handle bars and grips & damper for about $300 bucks for the guys that strip hayabusa's so they can put the engines in custom cars look on ebay should be some near you. $300 bucks is the max you should pay
 
#17
Hmmm quickest and cheapest way to fix this I had similiar issues with mine is buy a complete front forks and yoke set usually comes with handle bars and grips & damper for about $300 bucks for the guys that strip hayabusa's so they can put the engines in custom cars look on ebay should be some near you. $300 bucks is the max you should pay
Are you saying changing the front end of your Busa fixed this?
What was wrong with the front end you had?
 
#19
my front didn't feel planted when i was pushing the bike hard in the corners and on really going for it acceleration would sometimes tank slap.. doesn't happen now
 

kjcili

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#20
think i figured it out. i've had a brake pulsation for some time, and today I was actually watching my forks and front tire as I was getting on the brake pretty solid, and yeah, the tire is dancing with the brake pulsation, so I'm gonna figure thats gotta be the deal.
 

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