Hyde Fork Brace

I picked up a Hyde brace on table at a swap many moons ago. I installed it and discovered it introduced a way too much friction. Eventually I figured out that the two bores on the brace were not parallel. Then I recall the guy I bought it from told he had crashed the bike. Duh.
Undaunted, I decided to tweak the brace so the bores were parallel. The brace was off the bike. I used a couple of old stanchions, both run through the brace, one in the vice, the other as a prybar. I got it pretty darn close, but on the last tweak, the brace fell in two! Duh!
Still undaunted, I jigged the brace and tig-welded it back to gether. The original casting is pretty thin in the center. i always hated the HYDE lettering, so this was an opportunity to make it disapear by running beads over it.
Back to vise with the stanchions, I was able to get it perfect: two parallel bores. Looks great. Stronger than new.
It sits at back of my bench waiting for the next front end rebuild.


Dommie Nator writes: "I've found from personal experience if it's got "HYDE" on it it will be crap."
I beg to differ. I installed a set of Hyde resets on my 1973 Triumph Trident. The ergonomics and build quality was excellent. And the metalastikc bushes that the alloy plates are mounted on totally tamed the buzz through the stock footpegs.

Stephen Hill

Perhaps it would help when going over a rough road and pot holes? I liked mine but it was big and made fitting a fender a chore.

Fast Eddie said:

Exaggerations of spoke breaking aside, I kinda agree with you.

But that then begs the question (the answer to which I do believe is beyond me) ... exactly what forces is such a brace designed to combat? And
how? And... the $64m question... how relevant is it??

I know that it is rare for someone to actually grasp my wheel twixt their knees, especially whilst I’m riding!

But, it does serve to raise the question as to what movement a brace is intended to prevent, and why, and how, and does that movement actually occur without one ??

I can say that I, personally, cannot detect the difference when riding with, or without, a brace.

Click to expand...

As it was explained to me

I do not believe a brace does any good at all, since the sliders are in effect linear bearings running on the stanchions - they are free to rotate on the stanchions. People claim that they help eliminate twisting effects generated by the single disc. Since the brake caliper is attached to a slider, which is attached by the axle to the other slider, the only way you get twisting effect is if the stanchion tubes themselves are bending. Connecting the sliders together at the top does not make the assembly stiffer, and as several people have mentioned, it will generate more stiction unless the stanchions and sliders are perfectly true and the brace is set up perfectly true.
Unlike the somewhat flimsy Triumph arrangement, Norton chose a fairly stiff design for attaching the axle anyway. I spent quite some time thinking about this before giving up on the idea of a fork brace. I think it's a poor solution to a problem which very few people actually can feel, the benefits are mostly in the mind of the rider.

I do find the great fork brace debate interesting, and since Comnoz took fun out of oil debates, and since it’s the Christmas holidays, we gotta run with what we got...

But, being serious for a moment, I would love to hear from someone who actually knows something about the subject, so please chip in if you’re that person!

o0Norton0o, I know you were offended by the crudity of the physics, but the rough n ready demonstration was simply intended to show that IF such similar forces are exerted by the relationship between tyre and road and motorcycle under hard braking... the Hyde brace would still allow them to happen (my man was not busting a gut, and a 400lbs+ motorcycle plus rider, braking hard at 100mph+ would exert far more force I’m sure), in which case, the braces FUNCTIONALITY would seem to be in question...

Conversely, IF such forces are NOT exerted... then the braces PURPOSE would seem to be in question...

Either way, the brace seems to be in question!


IF the forces are as shown by acadian, surely this would be felt at the bars as the bike tried to turn slightly under braking? Personally I’ve never experienced that with a bike that has good wheel alignment etc.

My layman’s thoughts on the subject are therefore that if all important alignment is correct, and the suspension is functioning properly at both ends, then perhaps a brace is negated and the wheels will find their own points in space due to centrifugal force and with undulations taken care of within the range and control of the suspension at either end?

I would caveat this however by saying that I’d assume modern motorcycles with their huge potential for speed and even huger potential for braking forces may be a different discussion entirely when ridden at the limits of their performance?

Well Nigel, Your man by virtue of his test changed the way leverage is applied to the wheel to demonstrate his point, so his point may be valid, but his test certainly is not. It would be like comparing you grabbing a socket with your hand to twist off a tightened bolt verses connecting a breaker bar to the socket and applying force to the bolt. Does the breaker bar prove you can twist the bolt off with only your hand?

If he wants to twist the tire by grabbing it at the 6 O'clock position with one hand, while someone holds the handlebars, he would get zero deflection, and still the length of his arm would give him a longer lever than the tire's contact patch area would have as the forces on it attempt to twist the forks... Please, no bad physics should be an explanation for anything a person wishes to propose.

You mention Jim took all the fun of speculating about oil. That's because he designed testing to reflect the actual physics of the parts and the lubricants he was testing. The knee twist test doesn't reflect how force is applied while riding...

The thing that creates the great force while riding is the inertia of the bike and rider's mass, but it's still transferred to the forks at the 6 O'clock position through a very little lever length. IN fact that lever length is what gives the bike it's "trail" and causes the effect that stabilizes the wheel as it goes straight...

As was said, the 2 different types of braces do 2 different things.

The brace that connects the 2 sliders at the top, I think may do something,... It may be so little that it's not felt by a rider as an improvement in handling, but I would bet that if only one slider has a caliper attached to it with no fork brace attached, that slider (given all other aspects of both sliders are equal) will have both it's seals and bushings wear at a faster rate than the naked slider. The physics predicts this.

Having a brace that connects the sliders at the top, should help to share some of the wear on the seals and bushings.. How significantly?? I don't know, because I haven't tested it, so I can only speculate theoretically based on the physics!

As I said and wish to repeat, that doesn't mean the difference in mechanical geometry transforms handling in a perceivable way to a rider. I would think designing a slider with wider bushings that are spaced further apart would create a noticably better front end performance, and I would bet that has already been done on later model bikes, where as fork braces were not judged to be significant in enhancing performance so they did not continue to evolve... which would be a conclusion reached by consensus, not experimentation, and certainly not the "knee twist" experiment.

I installed mine years ago, and my memory is not very good, however I do remember I did install it for a reason.I installed it after I improved the one sided braking.When braking very hard , I could feel/see the forks twist , and thats why I installed the best brace I could find at the time, which seemed to help(see first sentence)

Sorry o0norton0o, but I still don’t get your breaker bar and socket analogy. This chap was simply applying very little force to demonstrate that the forks would still twist badly, just as they did on a similar bike without a brace.

Yes, you are correct to say he had the leverage advantage afforded by the handle bars, but still, he was a 60 odd years old bloke using little visible force.

The forces generated by a 400lbs+ motorcycle, plus rider, braking hard into a bend from 100mph+ would, I imagine, be significantly higher than old John Anderson was applying!

Nevertheless, we do at least seem to agree that a fork brace has questionable advantages to normal riders.

It's real good looking and strong looking but I would not fit one. A bud showed me his and I thought this looks strong ! Not.