Cheapest price fork brace???

[skids]

I notice a slight improvement on two of my xs11s using the TKat braces.
The third bike really improved. Maybe there was more slop in the guides in that bike. But what really made the most improvement in the third bike was adjusting the trailing are bearings.

[Cobia]

I agree with the proponents for the brace. My G always seemed slow to respond to turning input and liked to follow cracks on the road like a religious cult.
I am the second owner, bought it from a co-worker who babied it. The G sat in his garage for three years, after he switched to HD, and it rescued me.
Not being versed in the XSs at the time, I had it gone through stem to stern and they did it right. Yet, the response to steering input was not as crisp as I like to have. That changed dramatically for the better after I installed the TKat brace.
The response to input became linear, just aim and go w/out hesitation or delay from the front wheel.
So you can definitely put me down as a proponent for fork braces.

[b.walker5]

I'm in both camps on this one. I rode my 1100 for years without one, and only put one of after reading of the 'benefits' here. So, after waiting in anticipation for my TKat brace to travel half way round the world, I was a little unimpressed after I fitted it. The brace was beautiful, a real nice piece of engineering, but its affect on the bike was a little underwhelming. It certainly did stiffen up the front end, but almost to the point of being uncomfortable to ride. Maybe I was too used to the bike without one, or maybe something else was wrong, but I wound up taking it off again. Ahh, much better.
That said, when I went to fit the brace I discovered my front guard (fender) wasn't standard, was in fact off a Virago, and it had quite a thick brace built into it, in the form of piece of 3mm x 75mm hoop on the underside, but even the stock guard felt more comfortable to me than the brace.

The forks had been rebuilt, and had progressive springs and spacer, so everything in that dept worked as intended.

My 1300 doesn't have one, and has a plastic guard, but I don't think I'll bother putting one on that.

[James England]

It certainly did stiffen up the front end, but almost to the point of being uncomfortable to ride..

you must have installed it incorrectly. A fork brace can't make a bike uncomfortable to ride. If it's not installed correctly, it could have interfered with the fork travel.

[James England]

plus the fact it'll take the load off the slider bushings. Something to think about as those ARE among the 'unobtanium'.

what bushings? The European bikes don't have bushes at all in the fork sliders. Do the US versions have them?

[James England]

My 1300 doesn't have one, and has a plastic guard, but I don't think I'll bother putting one on that.

Much thicker tubes on the 1300 though. And, as you say, there's not even a brace in the front fender.

I fitted one to mine and I must say, on that particular bike, it doesn't feel much different...if at all. But I feel better with it on and it looks nice... The brand is Coerce from www.japan.webike.net

[crazy steve]

what bushings? The European bikes don't have bushes at all in the fork sliders. Do the US versions have them?

James, I'd be surprised if the euro versions don't have the upper bushings. These are pressed into the top of the fork lowers and are present on all US models. The Specials/XJ have an additional bushing on the lower end of the fork tubes, the standards lack these. The uppers aren't shown as a replaceable part though...

[James England]

James, I'd be surprised if the euro versions don't have the upper bushings. These are pressed into the top of the fork lowers and are present on all US models. The Specials/XJ have an additional bushing on the lower end of the fork tubes, the standards lack these. The uppers aren't shown as a replaceable part though...

no, they definitely don't have bushes. The fork sliders are just alloy and the stanchions slide into them. Definitely no bushes. I've seen it mentioned in a manual somewhere too...once the sliders get worn, usually becoming slightly oval, they have to be replaced.....

[D0wn5h1ft]

Not so sure about that. Any motorsport engineer understands increased rigidity results in a better more repeatable/predictable machine. The flex from the forks is just plain due to the limitations of the design/materials. A side affect, so to say, from the design.

I think its easy to say the designers seemed to be focused on power and comfort and less on handling. "Flickability" really wasnt a consideration at that point in history with liter bikes, or at least it was "tolerable".

The front fender offers little support to the forks. They are just sheet metal and can be flexed by hand if removed... Taking the fender off has no effect on moment of inertia (WTH are you talkin about?). Moment of inertia is the mass property of a rigid body that defines the torque needed for a desired change in angular velocity about an axis of rotation. In common talk, think heavy flywheel = large moment of inertia.

Yes, to the definition you pulled from wikipedia: "Moment of inertia is the mass property of a rigid body that defines the torque needed for a desired change in angular velocity about an axis of rotation". But unfortunately, you typed the wrong thing into google when you went to fact check me. What you should have typed is: Second moment of inertia, also known as the second moment of area because that is clearly what I was referring to. http://en.wikipedia.org/wiki/Second_moment_of_area

In short, when you remove material from along the direction in which the force is being applied (in our case transversely across the forks) you reduce the second moment of inertia in that that direction. Meaning the rigid body becomes less "rigid" in the sense that if thought of as a cantilever beam (with the fixed end obviously being the triple trees) we are lowering the spring constant thus making it easier to displace. To deny that the fender does not have ANY contribution to the rigidity of the forks is simply not correct.

Take a look at this thread where WildKat made a post suggesting that further weakening the reinforcement in the forks could lead to problems:

http://www.xs11.com/forum/showthread.php?t=17374&page=2

When I said "never meant to be" I was referring to the design process. The forks were engineered to allow for a bit of flexibility to respond well to the stresses the front suspension would endure. As a result, the handling on the old yammys are relatively poor because that built in stress-relief causes a degradation in handling performance. By adding fork braces your are trading stress for strain, meaning that as stress is applied to the forks, instead of it being relieved through strain (the deformation, or "flexing" of the forks) it builds up across this fork braces and results in higher shear forces on the forks (which they can obviously withstand).

Take a look at this very basic example of a stress-strain graph (and yes, I know it's an example of axial loading but bear with me):


As you can see the stress increases until a certain point where the body then begins to deform (strain). If we prevent this deformation from happening then instead of the increase in stress leveling out, it continues to build up until the point at which the shear forces become to great and the forks buckle (not suggesting this would ever happen as they would bend long before this point).

To conclude, I didn't mean to imply that fork braces were a bad thing just that it wasn't necessarily a design mistake that NEEDS to be fixed. Does it improve handling performance? Absolutely. Does it add additional stress to the forks that they may or may not have been designed for? Yes. Does this mean that your forks will buckle or bend? No, because they can handle it. I apologize for the confusion in my wording. I'm an engineer and we don't always "talk too good".

[jetmechmarty]

I was left pretty much unimpressed when when I put a fork brace on my Special. One day after some carburetor work, I crashed driving up the mountain. It was determined that my front end was pretty well worn out. I replaced the springs with custom straight rate and added emulators. The were pretty well freshened up. I also bought some decent shocks with springs appropriate for me. After that, it's like a new bike. The fork brace might make more of a difference now, but I don't care to take it.off to test.the theory.

The bottom line is that it's not a majic bullet. The fork brace will likely make a good front end better.

[WMarshy]

... But unfortunately, you typed the wrong thing into google when you went to fact check me. What you should have typed is: Second moment of inertia, also known as the second moment of area because that is clearly what I was referring to.

OK look, dont let your head get too big you might get top heavy and fall out of your chair. Clearly you didnt type that because you wrote "moment of inertia" and not second moment of inertia in your original post and seem to know there is a difference. Type what you mean and we wont be left to interpret it. Secondly, I'm not trying to prove I'm smarter than anyone here and I suggest you try to do the same and be a little more humble when someone points out a mistake.

The simple point I was making was 1) you used moment of inertia incorrectly in your post. 2) fender offers little rigidity because its whimpy and can be flexed by hand. 3) there are several factors as to why there is flex in the forks but it wasn't a design input like you infer "had flex designed into them", but rather an output of the product built.

In short, when you remove material from along the direction in which the force is being applied (in our case transversely across the forks) you reduce the second moment of inertia in that that direction. Meaning the rigid body becomes less "rigid" in the sense that if thought of as a cantilever beam (with the fixed end obviously being the triple trees) we are lowering the spring constant thus making it easier to displace. To deny that the fender does not have ANY contribution to the rigidity of the forks is simply not correct.

Nor did I read anyone saying the fender added NO support...

When I said "never meant to be" I was referring to the design process. The forks were engineered to allow for a bit of flexibility to respond well to the stresses the front suspension would endure. As a result, the handling on the old yammys are relatively poor because that built in stress-relief causes a degradation in handling performance. By adding fork braces your are trading stress for strain, meaning that as stress is applied to the forks, instead of it being relieved through strain (the deformation, or "flexing" of the forks) it builds up across this fork braces and results in higher shear forces on the forks (which they can obviously withstand).

Whuuut? lol Stains is always present when a member is stressed (load applied). Deformation is always taking place when a member is stressed. Permanent deformation doesn't occur until you reach the yield point. If you reach yield the forks have failed. The forks flex (deformation) could be corrected if the design used a tougher material or increased the size of the tubes but they decided to do neither. That is why the flex is an output/side-effect or inherent flaw of the design.

To conclude, I didn't mean to imply that fork braces were a bad thing just that it wasn't necessarily a design mistake that NEEDS to be fixed. Does it improve handling performance? Absolutely. Does it add additional stress to the forks that they may or may not have been designed for? Yes. Does this mean that your forks will buckle or bend? No, because they can handle it.

No, its doesnt add stress to the forks because the the load and force applied to the forks is the same unless you are riding harder and pushing the bike further because it is handling better... Just making the fork assemblies more rigid via the brace does not add stress to them...

Its not that it needs to be fixed, its just and enhancement. Just like pepole who buy after market head lamps or steering dampeners etc...

http://xaxor.com/funny-pics/funny-go-home-youre-drunk-memes.html/attachment/go-home-youre-drunk-memes6

[D0wn5h1ft]

I'm sorry if I came off sounding like a smart a$$. I was just trying to engage you on an intellectual level because I'm really passionate about motorcycles, their operation, and how my limited experience/education can be applied to different aspects of performance. I misspoke originally and that is what has lead to this and I apologize for that. I'm glad we can come to some sort of consensus on the validity of fork braces as performance enhancing components.

The only points you made that I disagree with are:

When you say that strain is always present (which it is) but suggesting that it is the same both with the fork braces and without. It's the same idea as a fishing pole, a short fishing pole has higher stress at the base of it than a long fishing pole because the load at the tip is more evenly distributed. When you install the fork brace you are inducing another "fixed" point along your cantilever other than the triple tress causing it to have "high stress" point in the middle of your forks which, like I said, it may or may not have been designed for.

And your last point which the reasons are the same as above.

[crazy steve]

One thing that should be noted is the Special fender is a lot stiffer than the standard one, so a fork brace on those probably won't show as much improvement. With that said, I've never been all that impressed with fork braces except on my chopped Sportster but with no fender, a 49 degree rake and 4" over forks, it needed the help.

[WMarshy]

I'm sorry if I came off sounding like a smart a$$. I was just trying to engage you on an intellectual level because I'm really passionate about motorcycles, their operation, and how my limited experience/education can be applied to different aspects of performance. I misspoke originally and that is what has lead to this and I apologize for that. I'm glad we can come to some sort of consensus on the validity of fork braces as performance enhancing components.

The only points you made that I disagree with are:

When you say that strain is always present (which it is) but suggesting that it is the same both with the fork braces and without. It's the same idea as a fishing pole, a short fishing pole has higher stress at the base of it than a long fishing pole because the load at the tip is more evenly distributed. When you install the fork brace you are inducing another "fixed" point along your cantilever other than the triple tress causing it to have "high stress" point in the middle of your forks which, like I said, it may or may not have been designed for.

And your last point which the reasons are the same as above.

Your really not introducing a new fixed point though. You analogy of the long vs short fishing pole is a bad example and irrelevant to the forks scenario because the forks are staying the same length. You really should draw a FBD to understand what the fork brace is doing and how forced are being transmitted.

Essentially what you have is 2 cantilevers (fork tubes) which share an anchor point (triple tree). The parallel tubes are fixed together at the end through the axle bolt. Transverse loading of the forks are applied at the axle and the fork tubes have the highest stress at the fixed end at the triple tree.

Now add a joining member (fork brace) between the fork tubes and apply the same load as above. The stress developed at the triple tree is going to be the same or slightly less because of the added rigidity of the lower half of the forks being connected together.

[James England]

Blimey, this thread is getting heated. Calm down you two. Everyone else can ponder that unintelligible (to most people) graph while you two kiss and make up......

Hey...why not post new topic with a poll about fork braces?