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Discussion Starter · #1 ·
I've never had a stabilizer on a bike before but have installed fork braces on on previous bikes to get rid of the death wobble. Do they serve the same purpose?
 

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No, they don't. The fork brace will reduce the twisting of the forks by "locking" them together. A steering damper or stabilizer helps to dampen the side to side wobbling along the steering head axis (think preventing tank slappers).
 

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... and a fork brace cannot be installed on "upside down forks" ....

This is a fork brace .. note that it's installed on conventional telescopic forks. When installed it makes it more difficult to "twist" the forks ... as if you stood in front of the motorcycle with the front wheel locked between your knees while you attempt to "twist" (turn?) the handlebars ... the brace will resist the forces attempting to tweek the front wheel out of alignment with the handlebars.

Note that the fork brace goes "up and down" with the front wheel and fork legs as the suspension cycles when you ride over bumps.

Bicycle Tire Bicycle tire Bicycle frame Wheel


Bicycle part Wood Nickel Silver Font


Tire Wheel Bicycle frame Bicycle tire Automotive tire



Someone else needs to pick up from here and explain/demonstrate a steering stabilizer ... supper's ready and my wife's tappin' her foot .... gotta run!

:)
 

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1991 Ducati 907ie, 1991 Ducati 900SS, 1991 Ducati 851 Strada
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2 completely different things, The fork brace helps lock the the forks in place so they do not twist--this amount may be very slight but it makes a big difference when pushing the motorcycle through a corner--without the fork brace ( depending on what fork setup is on the motorcycle) & ( depending on how aggressive you ride) you may see little benefit or you may see a huge benefit----The steering damper helps control side to side oscillation of the front end.--aka a tank slapper which can be caused by a number of factors. ---I race AHRMA vintage--I run a 1972 BMW R75/4. I have a steering damper, a fork brace, a heavy duty upper triple clamp & a few other mods to make the front end rock solid--again this is using a stock style front end--( again with many mods) --This alone helps a lot but by no means is it the end of the suspension mods.
When we are talking Ducati it all depends on which year & model you have --you didnt say---upside forks as far as I know there are no fork braces available--steering dampers there are many, but it depends again which motorcycle you have as too whether or not you even need one,
I have 3 Ducati's all are 1991 models----907ie, 900ss & 851 --Now I do not push these motorcycles anywhere close to their potential & I do not do track days on them--But I have friends that do push theirs and all have said the same thing--Steering damper on those models totally no needed. & they are dragging their knee's thru the corners.
You have to ask what you expect from the motorcycle & what you want it to do,
Just as a note--In 1975 when BMW won the superbike championship with their R90S models, nobody was making a fork brace--BMW aka Butler & Smith used as a fork brace an extra lower fork bridge w/ the steering stem removed mounted lower on the front forks If memory serves about 5 inches below the stock fork bridge--this made 4 points of isolation --upper bridge, --lower bridge, --extra lower bridge & ft axle --all this made it rock solid-& this was with normal forks--( not upside down forks)
 

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Discussion Starter · #6 ·
Thanks guys for all the info. I'm not understanding the damper reducing an oscillation concept. Perhaps I haven't experienced it. As I originally stated, I have utilized fork braces before. I experienced wobble on 2 previous bikes and installing fork braces was amazing. I just purchased a Monster S4 that I have not driven more than once at this current time due to insuring its brought up to snuff after sitting for 5 years. So I haven't experienced any issues per say with it, just trying to understand the use/purpose of a damper. I don't think it would serve the same purpose as you experience on a 4X4 truck.
What does the oscillating feel like? I'm thinking it would be like a high vibration slowly or perhaps rapidly coming and going?
 

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Discussion Starter · #7 ·

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Discussion Starter · #8 ·
No, they don't. The fork brace will reduce the twisting of the forks by "locking" them together. A steering damper or stabilizer helps to dampen the side to side wobbling along the steering head axis (think preventing tank slappers).
Would this not be caused by an improperly balanced rim and tire or forks that are not equally balanced?
 

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Thanks guys for all the info. I'm not understanding the damper reducing an oscillation concept. Perhaps I haven't experienced it. As I originally stated, I have utilized fork braces before. I experienced wobble on 2 previous bikes and installing fork braces was amazing. I just purchased a Monster S4 that I have not driven more than once at this current time due to insuring its brought up to snuff after sitting for 5 years. So I haven't experienced any issues per say with it, just trying to understand the use/purpose of a damper. I don't think it would serve the same purpose as you experience on a 4X4 truck.
What does the oscillating feel like? I'm thinking it would be like a high vibration slowly or perhaps rapidly coming and going?
A rapid "wiggling" of the handlebars ... sometimes it can increase in it's intensity rather quickly ... handlebars wiggling faster and faster, wider and wider apart, until the grips are ripped from your hands or the bike throws you down on the street right on your face. It's where the term "tank slapper" comes from ... in reference to the handlebars slapping back and forth from full lock to full lock, your hands "slapping against the tank" ... hence, tankslapper.

The damper serves the exact same mechanical purpose as the steering damper on that 4x4 you referred to. It "dampens" any side-to-side (fast) movements so as to keep things more stable with less rider (driver) input.
 

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Would this not be caused by an improperly balanced rim and tire or forks that are not equally balanced?
The tire thing ... That's up and down imbalance ... instead, think of the handlebars moving side to side (left to right), like I detailed above.
 

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The only reason for a steering damper is to control headshake, a.k.a. tankslapper, a.k.a. wobble. If you’re not having a problem, you don’t need (or want) a steering damper.

Headshake is basically a dynamic instability. Once it gets going it’s hard to stop, so a velocity-dependent damper can be used to progressively decrease its severity. If you’re not familiar with it here’s an example:


Headshake is caused by a combination of factors: too steep a steering angle setting, too little trail in the design of the bike, too little weight on the front wheel (usually under acceleration exiting a corner), a certain bike speed, lean angle, rider weight, and of course a bump or series of bumps in the road to start it all going.

But unfortunately a damper just doesn’t work just during a headshake (high velocity oscillation of the handlebars). You also reduce the bike’s ability to transition into corners (low velocity bar movements) and more important, you increase the tendency of the bike to weave from side to side at high speeds. So, by its very nature a steering damper will spoil your bike’s steering to varying degrees.

That’s why there are adjustable steering dampers. The trade-off between handling feel and steering stability is a personal choice.

Track surfaces are smoother than typical roads, so often less damping is needed. Also, the steeper steering head angle is less stable (less self-correcting) so more damping should be considered when this setting is used.

See:
 

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Discussion Starter · #12 ·
The tire thing ... That's up and down imbalance ... instead, think of the handlebars moving side to side (left to right), like I detailed above.
Ok, I have experienced that. It was on a Yamaha 650 turbo, scared the shit out of me. I never did figure out the cause and parted the bike out after the 2nd episode.
I figured the frame must have had damage that I couldn't find.
So now that I know what it is, what is the cause? There are far less components and adjustable parts on a bike than on a 4X4 truck.
 

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Discussion Starter · #13 ·
The only reason for a steering damper is to control headshake, a.k.a. tankslapper, a.k.a. wobble. If you’re not having a problem, you don’t need (or want) a steering damper.

Headshake is basically a dynamic instability. Once it gets going it’s hard to stop, so a velocity-dependent damper can be used to progressively decrease its severity. If you’re not familiar with it here’s an example:


Headshake is caused by a combination of factors: too steep a steering angle setting, too little trail in the design of the bike, too little weight on the front wheel (usually under acceleration exiting a corner), a certain bike speed, lean angle, rider weight, and of course a bump or series of bumps in the road to start it all going.

But unfortunately a damper just doesn’t work just during a headshake (high velocity oscillation of the handlebars). You also reduce the bike’s ability to transition into corners (low velocity bar movements) and more important, you increase the tendency of the bike to weave from side to side at high speeds. So, by its very nature a steering damper will spoil your bike’s steering to varying degrees.

That’s why there are adjustable steering dampers. The trade-off between handling feel and steering stability is a personal choice.

Track surfaces are smoother than typical roads, so often less damping is needed. Also, the steeper steering head angle is less stable (less self-correcting) so more damping should be considered when this setting is used.

See:
That vid you shared is exactly what happened. So when it took place I quickly thought, DON'T hit the brakes. I did not rapidly drop off the throttle either and just gradually slowed down till the wobble stopped. I have often wondered what rapid deceleration would have done in that situation? Any knowledge on this scenario?
 

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Discussion Starter · #14 ·
The only reason for a steering damper is to control headshake, a.k.a. tankslapper, a.k.a. wobble. If you’re not having a problem, you don’t need (or want) a steering damper.

Headshake is basically a dynamic instability. Once it gets going it’s hard to stop, so a velocity-dependent damper can be used to progressively decrease its severity. If you’re not familiar with it here’s an example:


Headshake is caused by a combination of factors: too steep a steering angle setting, too little trail in the design of the bike, too little weight on the front wheel (usually under acceleration exiting a corner), a certain bike speed, lean angle, rider weight, and of course a bump or series of bumps in the road to start it all going.

But unfortunately a damper just doesn’t work just during a headshake (high velocity oscillation of the handlebars). You also reduce the bike’s ability to transition into corners (low velocity bar movements) and more important, you increase the tendency of the bike to weave from side to side at high speeds. So, by its very nature a steering damper will spoil your bike’s steering to varying degrees.

That’s why there are adjustable steering dampers. The trade-off between handling feel and steering stability is a personal choice.

Track surfaces are smoother than typical roads, so often less damping is needed. Also, the steeper steering head angle is less stable (less self-correcting) so more damping should be considered when this setting is used.

See:
I just reread your post and see that you gave the causes. That's very appreciated and helps alot to understand. Some of them appear obvious now but Im sure it's due to your great description👍
 

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I just reread your post and see that you gave the causes. That's very appreciated and helps alot to understand. Some of them appear obvious now but Im sure it's due to your great description👍
Hopefully you feel "better equipped" now. Knowledge is power.
 

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That's funny you should get into the conversation Stillrollinalong, it was your damper that got me thinking about what exactly they are correcting or preventing.
Thgats not my damper. I am on an ST because of geometry they rarely need a damper. Tha's why I asked what bike you are on.

The other thread gave me a quick way to show just what a damper is.
 

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That tankslapper video was crazy with the complete 360° spin. Never would have thought a bike could do that. Looked like a HD so I guess anything is possible and given his choice of riding gear I wouldn't want to see how the rider fared after that little get off.
 

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It doesn't take any defect to cause a tank-slapper. Just a set of circumstances to set up an oscillation. Every part of your bike can be described in terms of a spring, and each has it's own natural frequency. Sometimes those springs can oscillate in a way that they reinforce each other, causing the tank slapper. I had a huge tank slapper on the race track once, and on the next lap I could see big, crescent-shaped alternate skid marks left by the front tire. The best way to end a tank slapper is counterintuitive, you hit the throttle and make the front end lighter.
Of course modern sport bikes have much stiffer steering components and modern tires are fantastic, but the odd tank slapper can still pop up when the stars align just so.
 
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