TIRE CUPPING & DEATH WOBBLE

[FM-USA]

It does not explain all the possibilities of Death Wobble
but if you have tire cupping, hopefully this info helps.

[Nlmman47]

my tire is starting to cupping now. is it just normal wear or is it a sign of something more

[FM-USA]

Tire pressure low?
Worn front wheel bearings.
Rear tire pressure low?
Loose bearings in steering stem and/or swing-arm.

Balance Beads (basically) fixed one badly cupped Battlax tire.
B.B.'s smoothed out the tire rotation and cupped tire worn evenly. Got about 5k more miles out of it.

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[Rednaxs60]

Adding to the list. Weak/worn out suspension.

[FM-USA]

Adding to the list. Weak/worn out suspension.

AHHhhh, right. Forgot about that.
A weak or broken spring, low fluid fork leg would/could be the culprit.

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[WingAdmin]

I don't think cupping can be a cause of death wobble.

When a tire is cupped, it is usually a repeating left/right pattern of every 10 inches or so around the tire. Death wobble on our bikes is most prevalent at around 35 mph, particularly when decelerating. At 35 mph, the left/right cupping cycle would be hitting the ground more than 60 times per second. Death wobble is a much lower frequency oscillation, at between 4-10 times per second - it's the resonant frequency of the steering head assembly (coupled to the bike frame).

Death wobble has quite a few potential causes, but as a result of the grip loss from cupping is not going to be one of them.

Grabbing onto the handlebars lowers the resonant frequency of the handlebar system to below that which is induced by whatever is causing it. That's why death wobble often occurs when decelerating without hands on the handlebars (or only loosely holding on to them). Hold onto them firmly, that little bump won't induce the wobble, because the resonant frequency of the handlebars is too low.

[Nlmman47]

is there a way to check if it is my forks. i haven't changed the oil in them since i had it and i doubt the old rider did. i am going to change the oil soon as i get the gauge i order in. i want to make sure i get the right amount in there. i dont want to take the forks off to do that if i can help it. is there any way to check to see if it is the forks?

[newday777]

Many will give you various things to do but the only cure for tire cupping and the steering wobble is to replace the steering bearing set, and properly torque them.
Steering bearings are a maintenance item that most riders fail to replace thinking "naw they don't wear out.... "
Get tapered bearings sets not round ball bearings.

[minimac]

The combination of of replacing the steering head bearings and using balance beads cured my headshake and tire cupping issues.

[WingAdmin]

For cupping, anything in the front end that is loose can cause it: steering head bearings, wheel bearings, fork bushings. If the wheel can move in any other direction other than rotating or steering, then there's a good chance you're going to see cupping. It can also be caused by incorrect tire pressure, unbalanced tires and overloaded bikes.

Death wobble can be caused by so many things, it makes it very hard to track down. Anything loose or flexible, from wheel bearings to swingarm pivots can cause it.

[cbx4evr]

my tire is starting to cupping now. is it just normal wear or is it a sign of something more

This is Dunlops response to the cupping question:

You may not be able to entirely avoid cupping. Tire cupping or irregular wear is a somewhat common occurrence on all vehicles. On a four-wheel vehicle, you are advised to rotate your tires periodically to even out wear. Unfortunately, you do not have this luxury with a motorcycle because front and rear tires, unlike those on most four-wheel vehicles, are not interchangeable.

However, there are steps that can be taken to minimize cupping and uneven wear on a motorcycle: Maintain your motorcycle and particularly your front and suspension. Avoid hard braking whenever possible. Braking causes the tire to grab and wear in one direction. When braking is applied to the front tire, the load transfer over-flexes the tire and increases the tendency for cupping and uneven wear. Maintain your tire pressures. Under inflation and overloading of motorcycle tires are significant causes of cupping and uneven wear, particularly in association with hard braking and/or trailer use.

Once a tire begins to show signs of uneven wear, even following these steps may not improve the condition.

Tire companies can, and are, helping to minimize cupping and uneven wear but you, the rider, must do your part. Following the aforementioned guidelines will help avoid uneven wear.

[Nlmman47]

i just installed a fork brace. i believe its the super brace not blackwing. but it does make the front end tighter and more control of the steering. i still have the deceleration woble at 35 but it still helps on the leaning and steering. im happy with that i hope it would stop the wobble but i happy

[Sassy]

I don't think cupping can be a cause of death wobble.

When a tire is cupped, it is usually a repeating left/right pattern of every 10 inches or so around the tire. Death wobble on our bikes is most prevalent at around 35 mph, particularly when decelerating. At 35 mph, the left/right cupping cycle would be hitting the ground more than 60 times per second. Death wobble is a much lower frequency oscillation, at between 4-10 times per second - it's the resonant frequency of the steering head assembly (coupled to the bike frame).

Death wobble has quite a few potential causes, but as a result of the grip loss from cupping is not going to be one of them.

Grabbing onto the handlebars lowers the resonant frequency of the handlebar system to below that which is induced by whatever is causing it. That's why death wobble often occurs when decelerating without hands on the handlebars (or only loosely holding on to them). Hold onto them firmly, that little bump won't induce the wobble, because the resonant frequency of the handlebars is too low.

I disagree. When I bought my bike the tires were almost done, the front badly cupped, and had a severe wobble as soon as I let go the bars. The instant I changed the front tire with no other changes the wobble was gone. The bike didnt have a brace on it at the time and there was no detectable looseness in any suspension components front or rear.

[Nlmman47]

I don't think cupping can be a cause of death wobble.

When a tire is cupped, it is usually a repeating left/right pattern of every 10 inches or so around the tire. Death wobble on our bikes is most prevalent at around 35 mph, particularly when decelerating. At 35 mph, the left/right cupping cycle would be hitting the ground more than 60 times per second. Death wobble is a much lower frequency oscillation, at between 4-10 times per second - it's the resonant frequency of the steering head assembly (coupled to the bike frame).

Death wobble has quite a few potential causes, but as a result of the grip loss from cupping is not going to be one of them.

Grabbing onto the handlebars lowers the resonant frequency of the handlebar system to below that which is induced by whatever is causing it. That's why death wobble often occurs when decelerating without hands on the handlebars (or only loosely holding on to them). Hold onto them firmly, that little bump won't induce the wobble, because the resonant frequency of the handlebars is too low.

I disagree. When I bought my bike the tires were almost done, the front badly cupped, and had a severe wobble as soon as I let go the bars. The instant I changed the front tire with no other changes the wobble was gone. The bike didnt have a brace on it at the time and there was no detectable looseness in any suspension components front or rear.

Did you notice a difference in the front steering and the way the front feels after you put on the brace. i notice a big difference in the front outside of the wobble. but i do need to change the tire. and maybe it will make things even better. i feel the road and every bump it has. i do need to change the fork oil and see if that helps with that. and see if i can fix my left front brake it not clamping tight, i hear it dragging when i press my foot brake.i have bleed it but maybe try it again or i will have to tear it down and see. thanks for anything you can tell me

[Sassy]

To be fair the brace was installed over the winter so impressions would be a little vague with the 5 month lay up.
I believe the improvement for me is slow speed maneuvers over uneven terrain,. The front wheel felt as if it followed the terrain more without the brace causing me to put a foot down more often.
I dont know what if any maintenance has been done on the front suspension but tire and brace made the front feel rock solid on a 33 year old bike with 200,000k.

[FM-USA]

I don't think cupping can be a cause of death wobble.

When a tire is cupped, it is usually a repeating left/right pattern of every 10 inches or so around the tire. Death wobble on our bikes is most prevalent at around 35 mph, particularly when decelerating. At 35 mph, the left/right cupping cycle would be hitting the ground more than 60 times per second. Death wobble is a much lower frequency oscillation, at between 4-10 times per second - it's the resonant frequency of the steering head assembly (coupled to the bike frame).

Death wobble has quite a few potential causes, but as a result of the grip loss from cupping is not going to be one of them.

Grabbing onto the handlebars lowers the resonant frequency of the handlebar system to below that which is induced by whatever is causing it. That's why death wobble often occurs when decelerating without hands on the handlebars (or only loosely holding on to them). Hold onto them firmly, that little bump won't induce the wobble, because the resonant frequency of the handlebars is too low.

I disagree. When I bought my bike the tires were almost done, the front badly cupped, and had a severe wobble as soon as I let go the bars. The instant I changed the front tire with no other changes the wobble was gone. The bike didnt have a brace on it at the time and there was no detectable looseness in any suspension components front or rear.

I expect Scott to remove your post like he did mine soon.
Folks like you & I have experiences that's NOT in his realm of experience he posts very long explanations to support HIS theory and try to prove your/ours wrong.
BUT... it's his website, he's the dictator of it.

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[Sassy]

Well FM that doesn't change the truth.
Ive always respected Scotts input, videos and totorials plus really like the site and people on it.
Ive had different experiences on repairs or changes and posted them in the relatively short time I've been on the forum and don't recall any issue.

[Rambozo]

If your tire is cupping, something is wrong. That is not normal wear.

[WingAdmin]

I expect Scott to remove your post like he did mine soon.
Folks like you & I have experiences that's NOT in his realm of experience he posts very long explanations to support HIS theory and try to prove your/ours wrong.
BUT... it's his website, he's the dictator of it.

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I do not remove posts I disagree with.

The ONLY time posts have been removed is when they are extremely inflammatory or argumentative/wholly offensive.

[joecoolsuncle]

I expect Scott to remove your post like he did mine soon.
Folks like you & I have experiences that's NOT in his realm of experience he posts very long explanations to support HIS theory and try to prove your/ours wrong.
BUT... it's his website, he's the dictator of it.

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I do not remove posts I disagree with.

The ONLY time posts have been removed is when they are extremely inflammatory or argumentative/wholly offensive.

unlike other forums. like something ending with facts. i find this one of the most honest and factual forums available.

[WingAdmin]

unlike other forums. like something ending with facts. i find this one of the most honest and factual forums available.

That's actually the reason GoldwingDocs exists. I got tired of most of my posts on the "Facts" website being deleted by obnoxious admins who had taken a personal dislike to me, so I created my own website.

[FM-USA]

Well a post of mine in this thread was removed. It has MY experience which is FACT.
If there was something inflammatory maybe either I be informed of it or THAT part removed and I still be informed as to why.
We're all here to learn... good, bad or ugly.

BTW: This isn't the 1st time a post of mine was removed in GWD. Not counting one I requested deleted. That whole thread went bad and it was in your best interest, Scott, to just get rid of it.

I'm not here to disparage anyone but I couldn't miss the 39 'Thumbs Down' without reason(s).
I expect a few T.D. since I do things on my Wing that few would even attempt or think of trying.
But if my experiences aren't up to this sites standards...

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[FM-USA]

Well FM that doesn't change the truth.
Ive always respected Scotts input, videos and totorials plus really like the site and people on it.
Ive had different experiences on repairs or changes and posted them in the relatively short time I've been on the forum and don't recall any issue.

Thanks Sassy, no it won't change truth.
Scott's input I too respect, 99% of it. There's always an IRK somewhere.


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