Another Fork Brace Thread

[dennisgb]

I've read over most of the threads on adding a fork brace to the Commando and I keep wondering why there is so much negative information. I would think that the addition of a fork brace would be a good thing especially with upgraded brakes.

If a fork brace is installed properly and fork performance and function is not compromised can it hurt?

 

[bmwbob]

I'm a big advocate of a fork brace, but the braces available for Nortons is nil! :cry:

 

[dennisgb]

I'm a big advocate of a fork brace, but the braces available for Nortons is nil! :cry:

I found one on Ebay

 

[batrider]

I found one on Ebay

OK Let's see it.

 

[bwolfie]

http://www.ebay.com/itm/171152261079?ss ... :MEBDIX:IT

 

[Hobot]

1. If a fork brace needed one will feel like rubber bands connecting the bars to the axle, ie: a slight delay in jerking on bars...
[as in tight switch back lumpy gusty chicanes is about only road conditions severe enough to show this weakness in Roadholders so can take sweepers fine w/o a brace right into isolastic resonance weave/wobble zone w/o a worry from even factory Roadholders]
... before it acts on tire with a likely fork twist rebound shudder you may instinctively try to counter the delay, but human speed/force counter efforts just add to the rebound so gets more rubbery stretchy ineffective until ya let off to recover or loose it. Roadholders are plenty stiff to take one sided disc brake loads. Its possible to encounter fork twist **hot dogging** rough off road but not just crossing it with a normal sense of damage and injury avoidance. A brace can somewhat delay a tank slapper but that's a fairly minor brace function and will not prevent full onset YIKES.

2, So It takes some harsh to dangerous operation conditions few encounter before Roadholders would be helped by a brace.

3. Its very very very very tricky to get a brace to actually mount solid enough to actually brace and fork travel not to be restricted in some range where needed most or the whole range just crossing parking lot speed bumps.

4. They did run in the hundreds of dollars. No one making em for Cdo's > so extra $pecial cu$tom job now a day$.

5. They look cool and implies the pilot is able to load forks to actually appreciate the brace.

 

[john robert bould]

Seen these in the past, i always wondered when the forks twist what stops one side from unscrewing?

http://www.ebay.com/itm/171152261079?ssPageName=STRK:MEBDIX:IT

 

[mike996]

Had one; took it off.

The Hyde fork brace, regardless how it was oriented/adjusted created a misalignment in the forks which caused increased friction/abrasion between the tubes and seals - and probably between the tubes and lowers. Bike handles noticeably better without the brace and I can't find any reason to use one - at least with the standard fender. Maybe with a FG fender it would be necessary to prevent other issues that might be worse than increased friction.

 

[Hobot]

Now there are a few cycles that fork braces are a wise thing to do...

 

[dennisgb]

Had one; took it off.

The Hyde fork brace, regardless how it was oriented/adjusted created a misalignment in the forks which caused increased friction/abrasion between the tubes and seals - and probably between the tubes and lowers. Bike handles noticeably better without the brace and I can't find any reason to use one - at least with the standard fender. Maybe with a FG fender it would be necessary to prevent other issues that might be worse than increased friction.

Mike,

Okay I follow what your saying, but here is my question. If a person took the time to insure that the fork brace were aligned properly, and there were no friction or abrasion, why wouldn't a fork brace provide a benefit? Particularly when upgrading the brakes to modern specification. I don't see the little fender bracket providing enough support to insure that the fork tubes don't twist.

I don't plan on racing my bike or even driving too crazy in normal use, but a brace properly installed seems to me to provide a benefit...I can't find any reason why it wouldn't. Some may think it is not worth the cost, and that is an acceptable reason, but from a function standpoint I don't see why it wouldn't help.

Dennis

 

[Unclviny]

The cost is not the main issue here, getting the adjustment correct is nearly impossible and at best will take WAY too much time. While you are playing with the adjustment your forks are not going to work very well, this is the reason that a LOT of us have passed on fork braces for Commando's.

Vince

 

[ludwig]

The problem is not so much with the brace itself , but with the tripple trees .
Fork stanchions (should ) have practically zero clearance in the bushings .
A really solid brace , in combination with the wheel spindle , will make the 2 sliders act as one .
This means that the slightest misalignment of the stanchions , even a fraction of a mm , will cause binding .
Without a brace , each slider can follow its own way , so to speak , because there is enough elasticity in the forks to allow for some misalignment .
If some braces seem to work , that is because they still allow some movement , which in a way defeats their purpose .
( they work because they don't work ..) .
It is a trade off between fork rigidity and compliancy .
So if you insist on a brace , for starters begin by putting your stanchions in a lathe to check/correct the taper , etc ..
Even if you do achieve perfect static alignment , there is no garantee that it will stay so under load .
I would leave those Hyde braces for the posers .
Anyway , good luck with it ..

 

[Matt Spencer]

RICH Posers ! Winning bid:US $535.00 . doubt the sanity unless theyve more money than they know what to do with .

 

[dennisgb]

The problem is not so much with the brace itself , but with the tripple trees .
Fork stanchions (should ) have practically zero clearance in the bushings .
A really solid brace , in combination with the wheel spindle , will make the 2 sliders act as one .
This means that the slightest misalignment of the stanchions , even a fraction of a mm , will cause binding .
Without a brace , each slider can follow its own way , so to speak , because there is enough elasticity in the forks to allow for some misalignment .
If some braces seem to work , that is because they still allow some movement , which in a way defeats their purpose .
( they work because they don't work ..) .
It is a trade off between fork rigidity and compliancy .
So if you insist on a brace , for starters begin by putting your stanchions in a lathe to check/correct the taper , etc ..
Even if you do achieve perfect static alignment , there is no garantee that it will stay so under load .
I would leave those Hyde braces for the posers .
Anyway , good luck with it ..

Ludwig,

Thanks for a well thought out answer which finally helps to make sense of this to me. I hadn't thought about the fact that the two sliders essentially become one, although even with the stock set up the fender brace ties them together. A fork brace will make this much more rigid and thus the two sliders must be adjusted to allow them to move together...and I can see how this might be difficult to accomplish. I will see how it goes when I get the brace.

I did not pay $500+ for the brace...someone else put that up. I paid $100 with free shipping so not out much to try it. If I don't like it, I'm sure I can sell it for a tidy profit given the numbers quoted here

 

[Hobot]

The other little buggaboo is even if ya get yokes and tubes and bushes true enough while brace firm but slack freedom enough to function at rest, on the fly things flex/bend/bind up on the conditions that loads the brace to come into play. Peels RGM took long time frustrations fits and tests to get it to work for Peel, but mainly felt as raising the fork twist frequency high enough not to bother handling or tire grip or delay inputs too much, but for sure did not and can not really strengthen Roadholders not to twist and flex almost to same degree as w/o just faster to a blur at axle level. Peel does not need a brace for racer type riding, ie: keeping both tires planted in turns, only going faster/harsher than that into phase 3 & 4 where she low sides for the hi side launch off front or rear and catch the landings on front and rear. Same action trail brakers want to avoid I induced on Peel by over power over steering the wrong way and brace sure helped then. W/o Peel's 'one in a row' tri-links there is too much slish-slash of multiple factors it would of been almost impossible to sense what her brace was doing and what was doing it to the brace. Btw if fork sliders do bind up an instant in some range you will know it instantly d/t the reversed control and direction of jerk off to the side by mild in perfections in the path at speeds over ~15 mph. Binding stem bearing feel similar but to a lesser degree of out of control sense. Most the conditions that would load fork to point a brace might help will have forks pretty compressed so the bushes far apart for decent over lap stability. When Peel lands after launches out of holes or off lumps in pastures it smacked her and my spinal forks hard but still compressed about fully instantly for fully loaded bottom outs, so can't really think of a condition to strain forks on full and weakest state of extension. Well maybe one conditon, the translation of vertical to horizontal if riding a bluff face/canyon wall, which feels like a short jump to extrend forks then a hard helmet on yoke smack down as tires plant by inertia on the wall then again but lessor on returning to road surface. I got started on this by a tractor with hay forks suddenly filling whole two ruts path, so no creeping up into extreme handling for me, Do or Die nothing to loose terror I lucked out to pull off is all.
Now I practice it on milder shorter grass covered berms, not rocky walls thank you please Lord.

 

[dennisgb]

Hobot,

That makes sense. We are talking about static loading compared to real world road conditions. No way to know how that effects things until you try it. So I need to be cautious because even if I get it to feel right in the garage could still damage seals and bushings under load...getting a feel for this now. Thanks.

Dennis

 

[concours]

Had one; took it off.

The Hyde fork brace, regardless how it was oriented/adjusted created a misalignment in the forks which caused increased friction/abrasion between the tubes and seals - and probably between the tubes and lowers. Bike handles noticeably better without the brace and I can't find any reason to use one - at least with the standard fender. Maybe with a FG fender it would be necessary to prevent other issues that might be worse than increased friction.

Mike,

Okay I follow what your saying, but here is my question. If a person took the time to insure that the fork brace were aligned properly, and there were no friction or abrasion, why wouldn't a fork brace provide a benefit? Particularly when upgrading the brakes to modern specification. I don't see the little fender bracket providing enough support to insure that the fork tubes don't twist.

I don't plan on racing my bike or even driving too crazy in normal use, but a brace properly installed seems to me to provide a benefit...I can't find any reason why it wouldn't. Some may think it is not worth the cost, and that is an acceptable reason, but from a function standpoint I don't see why it wouldn't help.

Dennis

A common misconception about fork braces is what force they resist. Picture the fender mounting pads on the inside of the forks parallel. Now, picture front wheel/axle/fender removed... rotate each fork tube a bit in the same direction.. fender pads will still be parallel, but misaligned. This rotating motion is what the fork brace is designed to resist, so, a .125" thick "fender bracket" is actually quite effective at this. The level of riding you describe, you would never, ever feel any difference. Most all OEM designs include a heavy gage fender bracket to get the benefit of bracing, without all the added complexity.

+1 on most everything the 'Bot said in above post(s).

 

[Hobot]

Well fortunately if ya can pretty much slam forks most the way to bottoming and they actually do and then snap back up you got it safe enough to test ride on. W/o getting risky a brace can add some sense of smoother stability just tooling around delights. Each thing that helped handling in Peel also made her feel smoother and steadier easier to glide along and the brace subtracted another band/layer of vibrational noise form nucance road-tire texture and wind eddies, subtle but noticed. I think they are cool looking too and wish someone could work up something along the lines of the fender arch w/o having to fuss with the slider tube inter action. I could see how a brace might help trail braking which requires some bar holding against tire angled braking for less risk of chattering squreching out of traction. That's against my religion so leave it to others to find out for me.

Oh ugh, xbacker, the sliders can't twist much to matter as you describe d/t the axle connection preventing this as well as the fender strap and struts brace-ness.also that the stanchions are free to rotate in sliders so can't impose slider twist on their long axis. What happens, ugh, is the sliders pretty much stay solid square in relation to the axle but each tube can bend opposite directions some in their length above sliders to the upper yoke ~2 ft worth. Put front tire in cement and a long lever on top yoke and try to turn front tire to see the tubes bow in opposite directions fro & aft then just let go, standing on correct side of breaker bar. Heck just put ya knees on the tire and grab bars and tug some to see immediately, ugh.

What does twist as xbackslider describes are the two front down tubes by the cradle-engine skewing aginst the iso tabs, like twist torsion bars. Oh its only a silly mm or less but boy howdy thats a silly mm doubled when the rebounds strikes. Stick a screw driver through one and try to bend the tab, which ya can't but will see what does move. Rear patch pivots sideways though the rear iso which levers the front mount to slap the gaps side to side which gives forks a silly mm of jostle, that once resonate can escalate before ya know what went wrong.

Tried to video fall foliage and sort of did but screamed/cussed on slip in mud at garage pad, ditto some yards later on a fresh rained on cow patty, ditto on limb crossing that kicked a piece in shin and bounced front out an inch, then few hundred yards, ditto as rear washed out on a climbing turn on just enough power to keep climbing about 30 mph, then DITTO over almost telephone pole tree fall hidden by long shadows across path and leaves and dirt colors same as surrounds, crused at having to nail throttle into MX'r to lighten front so hopped over with just a wiggly landing to steady, then timidly fine on short return till almost through drive way wind knocked down a vine, after a slight delay resolved IT Had significant thorns on it not the expected grape vine again, so jerked reflex fork-bike toss away so it just brushed glove not ripped across neck. All in 2o min within 2 miles of home. Got some ok video but main 'puter to post is dead till who knows when. Motorcycling is just plain crazy making.

 

[dennisgb]

Hobot,

The fork brace I bought is the one with the hoops that go over the fender and it mounts to the slider bolts at the fender bracket.

http://www.ebay.com/itm/271300793546?ss ... _34wt_1018

This one is different than the cast ones that mount to the fork tubes. It may actually allow some movement...but likely not. It will likely need to be shimmed to insure smooth slider operation...won't know until I get it. I am going to adjust everything without oil in forks so I can hand slide things up and down. Then test with oil. Then on the road.

I think I have a good understanding of what I need to do, and if I don't get there or am not comfortable with it on there, will just chock it up to learning curve and take it off.

Dennis

 

[Hobot]

Oh ok that's the most likely kind of brace to get to work as expected. It has some appeal to me as a 3rd hard point to mount deer-dog-goat guard on. It can also be used to mount a bar across that sticks out enough to both rest feet forward on long hauls and catch bike on slow tip overs. Its a strain to shove down on forks standing still so i tend to roll forward and lock brake to help my inertia compress em. Let us know how it works out eventually and feels to you. Ya can loose a pound or so by getting Greg Fauth's alloy internals and other features i love to test to the max on. Its bright and nice out mid day and gap in appointments but still too shy after yesterdays timid short ride events so don't got the spittle to try today.

oh oh just got a call from out of town people so got a reason to steal a ride before freeze hits later, chow.