Fork Braces

after beck's post about the fork brace for the 4th gen's making a big difference, I started doing the math on how much it would cost to machine one myself. For one, probably about the same as the one he posted. But a production run, I'm pretty sure I could get it a chunk under $100 complete. I have access to 4th, 5th, and 6th gen bikes, so I can test fitment without a problem. Just wanted to see if there was any interest in any of these for me to even see what it would cost to do a run and how complete the product should be.

Meh! I don't think it's the brace thats needed so much as replacing the crappy front end that Honda equips the viffer with. I had the entire front end rebuilt by Race Tech on a 6th gen, and it's like it's glued to the road without a fork brace. What a difference, I think and therefore it does without shudder. Of course, this is a much pricier option, but ddddamn!... what a difference!

I've already done the complete Race Tech rebuild on my 98. That said, if this was a reasonable priced add on that would enhance the racetech improvement then I'd probably be interested in it. I like powder coat black or bare aluminum. Anything that make the suspension function better helps tires wear evenly is worth the money in my book. Smooth is fast.

I've got a worked front end on my 6th gen, and it flexes in the tight stuff.

I would be interested.
This being a tough economy, I'd recommend to keep price as low as possible.
However, some simple pocketing (if in fact it is simple) will go a long way, b/c a slab of aluminum would just look wrong there IMHO. However, if it comes to making a choice bet. paying <100 for no pockets vs. close to 200 with, I'd choose the former.
As far as color, I would advise to offer it as an option. Maybe the pocketing too, come to think of it.

Alright, there's enough interest, and I'm on my way to learn a new cad system so I can make the tool paths.

Just before anyone asks the stupid but important question, yes the section that clamps to the forks will be polished.

For the second poll question, that can be done on a per-order basis.

Just need to start gathering dimensions now. Going to put them up on my first post so they're easier to find. Oh, and anyone have a clue how many microns the finish on the fork clamps have to be?

[image: View Post]YoshiHNS, on Aug 24 2009, 09:55 AM, said:

Alright, there's enough interest, and I'm on my way to learn a new cad system so I can make the tool paths.

Just before anyone asks the stupid but important question, yes the section that clamps to the forks will be polished.

For the second poll question, that can be done on a per-order basis.

Just need to start gathering dimensions now. Going to put them up on my first post so they're easier to find. Oh, and anyone have a clue how many microns the finish on the fork clamps have to be?

Where on the forks are you planning to attach the brace?

Pretty much in the same place. Right above the fender on that flat spot. Looks like the 5th and 6th gen both have that black protective piece over the flat spot, and I think I would rather remove those and have the brace right on the forks than on that black piece. So that's going to be a fun job.

sounds like a great project can i have one sent to me in the uk please. :biggrin:

I prefer three piece designs, like this rough 2min model here:
[image: Posted Image]

Hate to put the horse before the cart here, but has anyone ever bothered to, uh, prove that fork braces have a beneficial effect on street-ridden motorcycles? A real test, not simply anecdotal evidence...

Ciao,

Evidence like THIS

Can't give ya a nice cad drawing yet. Forgot all my cad programs are in rochester, and i'm in cleveland until I get two cars and a CNC working.

First trying to figure out how I can make it without those vertical bolts and/or how to make it with as little machining as possible.

Of course, the biggest problem is that my dad moved out the nice, small, CNC mill I was going to do all the work on. We have another one, but I don't exactly need the 8ft of travel this thing has.

OOh, just got a breakthrough. Gotta go see if it'll work.

what a great plan will keep my eye on this how do you feel about shiping worlwide??

I'd ship overseas. There are those international priority boxes that make things fairly simple. Bit on the pricey side. But that's for when I actually have a product that works and I am satisfied with.

I'll see what interest there is on the OzVFR site. I have an R1 front end for my bike but I might be interested in one for my wife's 4th Gen.

I put other up there for those who did a fork swap (RC51, R1). I just figured that there were plenty of options for those as well. Fork braces aren't that complicated geometry wise, so if my design goal is met, it shouldn't be a problem making the changes for different fork spacing/sizes. Or at least that's what I'm hoping.

I think the guys that have swapped to USD forks like the RC51 parts will likely need a frame brace before they ever need a fork brace. ;)

[image: View Post]JZH, on Aug 24 2009, 08:06 PM, said:

Hate to put the horse before the cart here, but has anyone ever bothered to, uh, prove that fork braces have a beneficial effect on street-ridden motorcycles? A real test, not simply anecdotal evidence...

Ciao,
Why don't you just give it a try yourself JHZ.
That's all it will take to change your mind about fork braces which IIRC, you noted that you think are just uneeded unsprung weight on the front end (Frankly, I think the weight is negligible).
I was also skeptical it will have an effect on my VFR as much as it did on my much smaller, lighter Hawk GT, but it definitely did make a difference.
As I noted, the fork brace does not provide the mega "boost" in performance to what you might get with an RC51, 945RR or R1 front end usd transplant (no a fork brace will not make your bike track ready. That will involve at least an upgrade of internals because the VFR has a softly sprung and damped front end out of the factory.), but it definitely does enhance the OEM fork's function/compliance by eliminating most of the flex induced stiction on the front suspension.
I think it's a good plug and play, easy mod for us that do not have the budget to do full front end transplants and can further be enhanced, for sure with a front end internal overhaul if you have mega miles on your bike.

Beck
95 VFR

[image: View Post]Beck, on Aug 24 2009, 11:19 PM, said:

but it definitely does enhance the OEM fork's function/compliance by eliminating most of the flex induced stiction on the front suspension.
I think it's a good plug and play, easy mod for us that do not have the budget to do full front end transplants

It sounds very interesting and might be worth a shot. It makes you wonder why Honda doesn't include them in the stock design. It would have cost Honda two bucks to include one in the first place.

[image: View Post]RE-Agent, on Aug 25 2009, 12:51 AM, said:

[image: View Post]Beck, on Aug 24 2009, 11:19 PM, said:

but it definitely does enhance the OEM fork's function/compliance by eliminating most of the flex induced stiction on the front suspension.
I think it's a good plug and play, easy mod for us that do not have the budget to do full front end transplants

It sounds very interesting and might be worth a shot. It makes you wonder why Honda doesn't include them in the stock design. It would have cost Honda two bucks to include one in the first place.



Might be one of those "fear-factor" situations. People might wonder why it "Needs" a brace, and be afraid of it...

I would be interested in one. Preferably not solid, but I don't really care if it's shiny or whatever. In order to move them, I'd suggest being as close to the $100 mark as possible, if not in the $80-$90 range. Probably sell like hot cakes in there.

Having the centers cut out a bit would also help with shipping costs. :warranty:

FWIW, this one that JamieD made for my VF750F is custom, and it cost about $125. The finish is not great though, not as nice as I would have liked anyway, it's rough. I don't really want the polished look on it, but I will end up polishing it before the bike is done because it won't look very good as-is when the bike is complete.

[image: Posted Image]
[image: Posted Image]

[image: View Post]YoshiHNS, on Aug 24 2009, 08:40 PM, said:

Evidence like THISNo, that's anecdotal. I mean a test under at least semi-controlled conditions, undertaken by people who regularly test such things (and hopefully understand suspension). Like you would expect for any other performance-related mod... :dry:

Fork braces used to be de rigueur back when they were putting 1,000cc engines in bikes with steel frames and 35mm forks, but as OEM suspension began to catch up with engine technology this was a mod that was dropped from most parts of the market. You can still get the original Telefix fork braces, but in recent years other companies have brought back the fork brace--even as OEM forks have grown comparatively massive.

I've seen a lot of interesting claims about fork braces, but nothing that I would consider convincing. (It probably doesn't help their case that racing seems to be trying to achieve optimum fork flex, rather than total fork rigidity.) But few VFRs ever see race tracks, so racing performance really isn't the appropriate test of fork braces. What puzzles me most is that the anecdotes of praise seem to emphasise the perceived low-speed benefits of fork braces. I would think that a fork brace would have the least likely effect at low speed, given that the fork unit as a whole is less likely to suffer from any sort of distortion at low speed than at high speed, and this effect would be less pronounced on modern bikes with modern, beefy suspension units.

I've got nothing against bling for bling's sake...but if someone makes a performance claim for something, I'm inclined to ask them to back it up.

Ciao,

[image: View Post]SEBSPEED, on Aug 25 2009, 06:32 AM, said:

FWIW, this one that JamieD made for my VF750F is custom, and it cost about $125. The finish is not great though, not as nice as I would have liked anyway, it's rough. I don't really want the polished look on it, but I will end up polishing it before the bike is done because it won't look very good as-is when the bike is complete.

[image: Posted Image]

Yeah, that's about what I came up with for making only one on our mill. A production run will really drop the price. Just really wish I had the small CNC mill back. Perfect size for this job, and I could write the program on the fly.

To me, that design is not ideal, meaning the combination of 5 parts to make the clamp. In my opinion(untested), the best setup would utilize no more than 3 parts to make a solid bridge.

Also, to make things a bit more complicated, I think a really nice brace would implement a raised rib inside the fork clamp area, which could positively lock into the groove that some of the VFR forks have at the tops of the sliders.

[image: View Post]SEBSPEED, on Aug 25 2009, 11:45 AM, said:

To me, that design is not ideal, meaning the combination of 5 parts to make the clamp. In my opinion(untested), the best setup would utilize no more than 3 parts to make a solid bridge.

Also, to make things a bit more complicated, I think a really nice brace would implement a raised rib inside the fork clamp area, which could positively lock into the groove that some of the VFR forks have at the tops of the sliders.

Pretty much what I was thinking. Hopefully with the 5th and 6th gen fork shields right where I want the braces, I can go off of those grooves.

Here's another successful run of the waterjet program I made for a VTR, which will also fit the 4th gen:
[image: Posted Image]

[image: View Post]SEBSPEED, on Aug 29 2009, 05:38 PM, said:

Here's another successful run of the waterjet program I made for a VTR, which will also fit the 4th gen:
[image: Posted Image]

That looks fantastic Seb!
It looks as stiff as a steel bridge That 1 piece design will have ZERO flex. I might just have to upgrade mine to whatever you guys come up with once the design is finalized! :fing02: :fing02:

Beck
95 VFR

But don't the VTR braces fit the 3-5 gens? Don't get me wrong, I'd much rather buy a custom piece from a VFRD member than an Asian-made E-bay piece, but it seems you'd have most interest in 6th gens, as there is no option out there, and most members on here are 6th gen owners.

I would definitely be interested--if I weren't unemployed at the moment... :(

[image: View Post]JZH, on Aug 24 2009, 02:06 PM, said:

Hate to put the horse before the cart here, but has anyone ever bothered to, uh, prove that fork braces have a beneficial effect on street-ridden motorcycles? A real test, not simply anecdotal evidence...

Ciao,

Are you asking us the members of the forum this? Because I doubt any of us has the resources and know how to do so. I'm sure manufacturers have done this real testing in the past. Heck I remember Honda used to put fork braces on their custom/cruiser bikes' forks in the early 80s, replete with logo on the front. I'd be willing to bet money that their findings were that traditional style forks, not usd, like those on VFR's do indeed flex and would benefit from a brace. This given amount of give was most likely written off as acceptable within the service life of the forks and wouldn't distort them permanently, etc.

Could they be made stiffer? Sure, but at added cost or redesign. Would we notice through our hands and butt-mounted g-meters the difference? Sure, but not enough to make the bean counters accept the added cost.

You really don't need evidence. We all know two HOLLOW steel shafts approx. 2-3 feet long will flex. Oh, wait, the fork assembly is made of separate cylinders that make them longer? Surely they wouldn't be prone to flex.

I'll trust others that say it works. Those that say a Type - R sticker makes them faster, not so much.

I'd also add that if they are useful they are probably on the racing bikes(I'll have to start looking for them at the races).....
I had one added to an old 72 Honda 360, and it made a lot of positive differences.

[image: View Post]fastbroshi, on Aug 30 2009, 06:29 AM, said:

[image: View Post]JZH, on Aug 24 2009, 02:06 PM, said:

Hate to put the horse before the cart here, but has anyone ever bothered to, uh, prove that fork braces have a beneficial effect on street-ridden motorcycles? A real test, not simply anecdotal evidence...

Are you asking us the members of the forum this? Because I doubt any of us has the resources and know how to do so. I'm sure manufacturers have done this real testing in the past. Heck I remember Honda used to put fork braces on their custom/cruiser bikes' forks in the early 80s, replete with logo on the front. I'd be willing to bet money that their findings were that traditional style forks, not usd, like those on VFR's do indeed flex and would benefit from a brace. This given amount of give was most likely written off as acceptable within the service life of the forks and wouldn't distort them permanently, etc.
Well, I'm curious if anyone has done any kind of testing, actually. Yes, Hondas used to come with OEM fork braces...and spindly forks. Some people might conclude that if Honda no longer considers fork braces necessary on modern sport motorcycles, they aren't. Amusingly, the fork brace manufacturers seem to rely on breathless testimonials and comical animations, rather than any kind of rigorous testing. Maybe Motorcycle Consumer News will one day do a fork brace "shootout", using one of their skilled testers in a "blind" test...

[image: View Post]fastbroshi, on Aug 30 2009, 06:29 AM, said:

Could they be made stiffer? Sure, but at added cost or redesign. Would we notice through our hands and butt-mounted g-meters the difference? Sure, but not enough to make the bean counters accept the added cost.
The added cost of a mass-produced OEM fork brace can't be very much--assuming that's all it would take to put the bike at the top of the supersport heap, surely Honda would have done it back when the CBR600RR debuted. What they actually did was fit 45mm conventional forks--quite a bit more expensive than slapping a fork brace on the F4i's 43mm forks, eh? (Sorry, that's an anecdote! :blush: )

[image: View Post]fastbroshi, on Aug 30 2009, 06:29 AM, said:

You really don't need evidence. We all know two HOLLOW steel shafts approx. 2-3 feet long will flex. Oh, wait, the fork assembly is made of separate cylinders that make them longer? Surely they wouldn't be prone to flex.
I admire your ability to so convincingly employ conventional wisdom in place of science! :blink:

[image: View Post]fastbroshi, on Aug 30 2009, 06:29 AM, said:

I'll trust others that say it works. Those that say a Type - R sticker makes them faster, not so much.
No comment! :biggrin:

Ciao,

ok, i've been a bit busy at work wiring a machine. Hopefully get the measurements and prototypes done this week. I like the thought of a one-piece design, but for sheer convenience I think I'll go with two, though making it one piece won't be too much extra work. I'll do the math on the shear of a 1/4" screw, but I have a feeling it's going to be good enough.

[image: View Post]Ryanme17, on Aug 29 2009, 01:36 PM, said:

But don't the VTR braces fit the 3-5 gens? Don't get me wrong, I'd much rather buy a custom piece from a VFRD member than an Asian-made E-bay piece, but it seems you'd have most interest in 6th gens, as there is no option out there, and most members on here are 6th gen owners.

I would definitely be interested--if I weren't unemployed at the moment... :(

The 6th gens also have stiffer/better forks to begin with, I've only experienced my VTEC forks flexing under the hardest of circumstances, on very twisty roads running a very hard pace, or while taking my chicken strips off within a single lane. In those circumstances I don't mind having a bit of flex. Don't forget the engineers know that the forks flex and take that into consideration when they design the chassis. They should have SOME lateral give to them.

Yoshi, do you want a .dxf file of the brace I have? You can play with that and make it 1, 2, 5 pcs, whatever. It will at least get you the slider and spacing dimensions to start with.

A .dxf file would be great. Was just going to ride the two bikes down to the shop and get the measurements there. Did you design that to have a bushing between the fork and brace? I saw the Coerce had a nylon bushing or something.

[image: View Post]YoshiHNS, on Aug 30 2009, 10:26 PM, said:

A .dxf file would be great. Was just going to ride the two bikes down to the shop and get the measurements there. Did you design that to have a bushing between the fork and brace? I saw the Coerce had a nylon bushing or something.
I think the bushing is a particular design approach by the manufacturer that can be deleted on other fork brace designs. I think they used it to deal with possible tolerance differences between different fork units, but the density of the material seems to be enough to get a good hard grip on the slider tops. The Telefix fork brace I installed on my Hawk GT came with thin strips of aluminum for shims instead I assume for the same purpose/reasons.

BTW, I think JHZ won't ever be satisfied unless someone sets up a jig with strain guages and lasers to quantify the added stiffness that fork braces add to the fork assembly. Sorry, but I don't have the funds or tools to do that. All I can say is, this is the second bike I installed a brace on and there definitely is an improvement with fork action, stiction reduction and resulting compliance. Went riding the twisties again yesterday and the front wheel tracked perfectly through the trip with the tires staying on the road giving me good feel and control through the bumpiest turns........but I guess, for some, my body and brain isn't a sensitive enough instrument to make that judgement...not even after over 30 years of riding all sorts of bikes in all sorts of conditions doesn't make me some sort of motrocycle chassis expert.........I guess that's a valid opinion I could respect......In the end, you don't have to buy a fork brace for your bike if you don't want to....

Beck
95 VFR

[image: View Post]SEBSPEED, on Aug 31 2009, 07:05 AM, said:

The 6th gens also have stiffer/better forks to begin with, I've only experienced my VTEC forks flexing under the hardest of circumstances, on very twisty roads running a very hard pace, or while taking my chicken strips off within a single lane.

Taking your chicken strips off within a single lane... :blink: :laugh:

We need video, Seb...

Once when out on a multiday ride, I jumped off a 4th Gen with a well-sorted front end (valving, springs, oil all modded and tuned) onto a stock brank new Vtec - first and only time I've ever ridden one - and the improvement in feel of the front end was immediately obvious. I eventually decided that it was mainly down to the beefier 43mm forks rather than anything else as there isn't a huge amount of difference in the internals between 4th and 6th Gen AFAIK. Note that prior to riding the Vtec I'd just done the best part of 2000km of 7/10ths fanging on tight bumpy mountain roads, so was pretty well tuned into how I wanted the bike to behave. I was impressed.

So, given that the VFR is a road bike and not a racebike, and is designed and built accordingly (and for a 60-70kg rider to boot!), anything that can help with overall stiffness is a good thing in my book - and as an additional thought related to the above, I don't think Vtec owners will see an improvement with a fork brace that is of the magnitude of that which a 3rd-5th Gen owner may see.

I appreciate JZH's point, it's quite valid, but if we assume that the fork brace provides *some* additional stiffness and helps tie the front end together just a little more, then when you combine that with a bunch of other small improvements you get an overall result that is obviously going to be a) better than just a fork brace on a stock front end) and b) perhaps something that is more than the sum of its parts... so, you do springs, oil, valving, new wheel bearings, fork set correctly in tripleclamps for minimum stiction, correctly balanced tyre with the right pressure setting for its type and your riding style - and voila, good sex front suspension! :cool:

[image: View Post]The Phantom, on Aug 30 2009, 06:08 PM, said:

Taking your chicken strips off within a single lane... :blink: :laugh:

We need video, Seb...

I'm sure it looks real squidly, but it's fun and good practice for avoiding surprises in the road. :blush:

This is one of those discussions where both sides have points but don't know where exactly to agree. :biggrin:

In my experience (no scientific jig building here!), anything below 41mm can benefit from a brace while anything above 41mm goes into the money best spent elsewhere category. And this isn't forgotten 80's tech. My 98 bandit 1200 had a hidden one built into the front fender mount. FWIW

To any doubters, I say this: buy one for $120 (or whatever), mount it (it's super easy), ride it, and if you don't think it's worthy, sell it on a forum for $90-100 and it will be gone in a day! :dry:

[image: View Post]JZH, on Aug 24 2009, 03:06 PM, said:

Hate to put the horse before the cart here, but has anyone ever bothered to, uh, prove that fork braces have a beneficial effect on street-ridden motorcycles? A real test, not simply anecdotal evidence...

Ciao,

Suspension is an art, not a science. I'm not sure how you'd quantitavily test something like this, anecdotes seem about the best one could get.

[image: View Post]Ryanme17, on Aug 31 2009, 02:38 AM, said:

[image: View Post]JZH, on Aug 24 2009, 03:06 PM, said:

Hate to put the horse before the cart here, but has anyone ever bothered to, uh, prove that fork braces have a beneficial effect on street-ridden motorcycles? A real test, not simply anecdotal evidence...

Suspension is an art, not a science. I'm not sure how you'd quantitavily test something like this, anecdotes seem about the best one could get.

I am not suggesting fork braces don't make forks stiffer--from their design it seems like they would have to--though a question remains regarding the sufficiency of the stiffness that already exists. I'm simply questioning whether "additional stiffness" is something worth having on a street-ridden sport-touring bike. For (anecdotal) example, the guy who suggested I perform an experiment on my ST1300's OEM 45mm forks, using safety wire, clearly expected the forks to bulge sufficiently at the top of the fork lower tubes to break the safety wire, which would have proved his point. However, this did not happen under even the most punishing London speed bump-attacking I dared. So, from a layman's perspective, either there was no substantial bulging to be arrested by a fork brace, or I somehow managed to achieve the benefit of a �100 fork brace for the price of some safety wire... :cool:

(BTW, fork braces could be tested the same way they test tyres. Get someone who could literally feel a pea on the road and have him (or her majesty) ride the same bike several times over the same course at increasing pace whilst not knowing whether the fork brace was installed or not for each run. Download rider impressions after each run and collate and analyse at the end. The truth will out.)

Ciao,

JZH, were you going over those speed bumps at a decent lean angle, while in a turn?

I am NOT trying to stir anyone's pot by asking, please don't take it that way. When I think of fork flex, the first thing that comes to mind is lateral(side to side) flex. So, in a left lean for example, the forks would flex to the right, with the left becoming shorter and the right longer, causing misalignment and stiction due to the axle being the only bridge. In hard left/right transitions, I experience the forks twisting beneath my hands. A fork brace would help deter these forces, more so in the first scenario, although certain design changes could be made to eradicate the twisting as well.

Now, to your point, as to whether or not this is truly beneficial or merely an ease on the mind; I can't prove it to you one way or the other with hard evidence. I will say that the theory sounds damn good though, and has common sense written all over it. I would be more concerned with analyzing the forces transferred to the steering head and neck of the chassis, as well as the subsequent raise of force on the swingarm pivots. All the physics are still at play, they're just being moved to another part of the bike by adding the brace.

Again, to me, it's not truly a matter of what exactly the brace by itself does, but rather how it affects the chassis as a whole.

[image: View Post]Ryanme17, on Aug 31 2009, 03:38 AM, said:

Suspension is an art, not a science. I'm not sure how you'd quantitavily test something like this, anecdotes seem about the best one could get.
I don't think having a major in art gets you a job at the R&D department of e.g. WP or �hlins. A degree in mechanical engineering might ;) Also ask yourself if you have evers seen fork braces in the catalogues of reputable suspension tuners. I am not saying that a brace is not beneficial for a pre vtec front suspension, It's just that when I read the claims made by the people who sell them I get a feeling they have no real clue about suspension either.
It is not that difficult to test the impact a brace has on the front suspension. Put the bike on a hydro-pulse and you can measure fork flex in any direction. Also fork sticktion, and the effect a brace has on fork sticktion, is something that can be measured whith the fork riding over simulated bumps.

JZH, I am not surprised the safety wire din't break, it is much too flexible. Maybe replacing it with a carbon string has a different outcome. Like you, I find the superbrace animation a bit comical. It only shows sideways flexing of the forks, nothing about the forks bending back and forth when riding over bumps or when braking. I have a slow motion video of that somewhere, maybe I can dig that up. Amazing to see how much older forks used to bend under heavy braking. So the claim that superbrace eliminates (all) fork flex is total BS imo.

[image: Posted Image]

[image: View Post]SEBSPEED, on Aug 31 2009, 03:17 PM, said:

When I think of fork flex, the first thing that comes to mind is lateral(side to side) flex. So, in a left lean for example, the forks would flex to the right, with the left becoming shorter and the right longer, causing misalignment and stiction due to the axle being the only bridge. In hard left/right transitions, I experience the forks twisting beneath my hands
I can't imagine the forks flexing much because of lateral load. If what you describe would happen than you will likely have more problems with brakes sticking. The forks will not be equaly loaded when going through a turn, your fork brace design can cope with that a lot better than the low profile braces like the superbrace. But isn't what you are experiencing more of a torsional flex with the wheel out of alignment with the bars?

A couple items that came to mind throughout this post:

1 - I am one of the poeple who would be interested.

2 - I think the reason the other makers went with a 5 piece design is for ease of installation. (trying to get the center piece of a 3 piece mount installed could be VERY challenging and mess up the paint / finish on the fork, IF you can even get it in there somehow)

3 - One thing that has not been brought up yet is "the weakest link". When you stiffen up the front fork at a certain area, you are removing some of the play that MAY have been designed into the fork. i.e. the old bend vs break idea.

4 - this leads me to my next idea. if worried about the shear strenght of the 1/4 inch bolts, it may be BETTER to use a 5 piece design. that way you can ensure that one of the bolts would break BEFORE one of the fork legs buckles BELOW the fork brace due to the increased load applied to that location.

5 - I raced Mtn bike for a long time. Back in the beginnning god created Mtn bikes....... (sorry tangent) No, really when I started riding mtn bikes, the front fork HAD to have fork braces on them because they had so much flex in them. As time went on, you no longer needed the fork brace as they were designing them to better. This does not mean that I think the 6th gen is perfect, quite the contrary, they have done a wonderful job of making it better, FOR 150lb riders. when you get someone my size (215) or bigger, then your are putting more weight, which equates to MUCH more force on the forks.

Sorry, I know I ramble on some times, but if I don't get these thoughts out, then I have other bad thoughts.........

[image: View Post]V4 Rosso, on Aug 31 2009, 10:24 AM, said:

[image: View Post]SEBSPEED, on Aug 31 2009, 03:17 PM, said:

When I think of fork flex, the first thing that comes to mind is lateral(side to side) flex. So, in a left lean for example, the forks would flex to the right, with the left becoming shorter and the right longer, causing misalignment and stiction due to the axle being the only bridge. In hard left/right transitions, I experience the forks twisting beneath my hands
I can't imagine the forks flexing much because of lateral load. If what you describe would happen than you will likely have more problem with brakes sticking. The forks will not be equaly loaded when goign through a turn, your fork brace design can cope with that a lot better than the low profile braces like the superbrace. But isn't what you are experiencing more of a torsional flex with the wheel out of alignment with the bars?


Yes, sorry, two different thoughts going at the same time there. I don't have a problem at all with "normal" riding. The hard left/right stuff isn't really a problem either, but it does bother me to feel that torsional flex happening. Now I could just stop doing that... or?

I don't know anything about torsional flex or lateral stability, or the like. I DO know that when I look down through the fairing at the forks when I'm under hard, controlled braking and see the forks wiggle front to back, maybe a fork brace may help.
Just my 2cents.
Jeff

Heck, the 4th gen forks are so wimpy that I could actually see it twist just when sitting on the bike and looking down the fork leg from above and just putting al little pressure on the handlebars to turn left or right. I could see the bars turning before I see movement of the wheel and tire below to the direction I am turning the bars towards. It was actually after I saw this that I decided to go ahead and find a brace for my 4th gen. After installation I did the same test and I cannot see the same twisting anymore . I do not think that 100% of the twisting is eliminated, it is impossible to do so with any mods on the front end. Materials will always have some flex to them, but it has been reduced to the point that I cannot detect it by sight anymore as I did before installing the brace.

Beck
95 VFR

[image: View Post]Beck, on Aug 31 2009, 12:24 PM, said:

Heck, the 4th gen forks are so wimpy that I could actually see it twist just when sitting on the bike and looking down the fork leg from above and just putting al little pressure on the handlebars to turn left or right. I could see the bars turning before I see movement of the wheel and tire below to the direction I am turning the bars towards.
Beck
95 VFR


Yep, me too. As cool as it would be to have a "scientist" or "science" confirm it, it's not a requirement. Being able to see it when just sitting there, and then mentally adding 2-3G of decell, couple with a 500lb bike and a 200 lb rider, all going around a bumpy tight turn......hmmm.. yep, I think they are flexing. A LOT.

Just a guess, no science to back it up. :biggrin:

[image: View Post]Terminex, on Aug 31 2009, 11:52 AM, said:

Sorry, I know I ramble on some times, but if I don't get these thoughts out, then I have other bad thoughts.........
And it also keeps the voices in your head at bay.

[image: View Post]Terminex, on Aug 31 2009, 05:52 PM, said:

5 - I raced Mtn bike for a long time. Back in the beginnning god created Mtn bikes....... (sorry tangent) No, really when I started riding mtn bikes, the front fork HAD to have fork braces on them because they had so much flex in them.
Or was it because back then all ATBs had rim brakes as opposed to discs. HS33 brakes are still frequently fitted with an extra brace, or brake booster as they call it.

[image: View Post]Insomniac, on Aug 31 2009, 07:48 PM, said:

I DO know that when I look down through the fairing at the forks when I'm under hard, controlled braking and see the forks wiggle front to back, maybe a fork brace may help.
A fork brace will be the least effective in that direction.

[image: View Post]Beck, on Aug 31 2009, 09:24 PM, said:

It was actually after I saw this that I decided to go ahead and find a brace for my 4th gen. After installation I did the same test and I cannot see the same twisting anymore .
That explains the many positive testimonials for better low speed handling.

[image: View Post]SEBSPEED, on Aug 31 2009, 02:17 PM, said:

JZH, were you going over those speed bumps at a decent lean angle, while in a turn?No, I wasn't. I'm willing to fly the flag for science; I'm not as willing to die for it!

[image: View Post]SEBSPEED, on Aug 31 2009, 02:17 PM, said:

I am NOT trying to stir anyone's pot by asking, please don't take it that way. When I think of fork flex, the first thing that comes to mind is lateral(side to side) flex. So, in a left lean for example, the forks would flex to the right, with the left becoming shorter and the right longer, causing misalignment and stiction due to the axle being the only bridge. In hard left/right transitions, I experience the forks twisting beneath my hands. A fork brace would help deter these forces, more so in the first scenario, although certain design changes could be made to eradicate the twisting as well.If this were the primary design goal, I would think the braces should be designed to be a thick as possible--like 25mm--at the clamps. Most designs seem to be dealing with the "bulging" non-problem. This lack of direction probably stems from a lack of analysis concerning the exact problem the design is supposed to solve...

I wonder if Larry's experience with fork bushing shims would be informative w/r/t the "designed-in" slop in the front suspension? Unfortunately, I can't remember his conclusion! The only other consideration I can think of is whether the fork brace would be manufactured to more precise measurements than the triple clamps it works with--if the measurements are not an exact match with the existing parts, the fork brace could actually create stiction where there was none before...

Ciao,

sorry there hasn't been much progress/updates with these. Was about to write how I was going to make the test pieces, and then realized that there was a major design flaw. :blush: . So I'm making a slight alteration to my design. Not too happy about it as I feel it loses a certain advantage, but still trying to make a two piece bolt on design work.

OK, I voted pro!

Now waiting anxiously to see the product. Posted Image

[image: View Post]Ryanme17, on 29 August 2009 - 12:36 PM, said:

But don't the VTR braces fit the 3-5 gens?


Can someone confirm/deny this? Does anyone out there have the fork spacing for a 4th gen? I'll post up the spacing for a 5th gen today if someone lets me know what part of the fork to measure from!

I'm interested in one for a 5th gen, make it a 3 piecer if possible, those are the easiest to install in what I've seen. Sebs one piece on that VTR is sexy, but requires a complete disassembly of the front end, yes?

Why do all of these kind of post always turn into debates? All the OP was trying to do, was get an idea of who would be interested in a fork brace, if one was produced. Now it has turned into a debate on the pros and cons of a fork brace.

[image: View Post]Ryanme17, on 29 August 2009 - 12:36 PM, said:

But don't the VTR braces fit the 3-5 gens?

Looks like they fit to me...

http://www.vfrdiscus...=1&#entry636624

[image: View Post]Hammerspur, on 07 December 2009 - 06:09 AM, said:

[image: View Post]Ryanme17, on 29 August 2009 - 12:36 PM, said:

But don't the VTR braces fit the 3-5 gens?

Looks like they fit to me...

http://www.vfrdiscus...=1&#entry636624


It will fit a 3rd/4th gen, but no one can tell me about the 5th GEN?! I've seen it mentioned that the forks are spaced further apart on the 98-01's but no one can tell me one way or the other :dry:

Yoshi, any news duder?

[image: View Post]2fast2young, on 09 December 2009 - 11:28 PM, said:

[image: View Post]Hammerspur, on 07 December 2009 - 06:09 AM, said:

[image: View Post]Ryanme17, on 29 August 2009 - 12:36 PM, said:

But don't the VTR braces fit the 3-5 gens?

Looks like they fit to me...

http://www.vfrdiscus...=1&#entry636624


It will fit a 3rd/4th gen, but no one can tell me about the 5th GEN?! I've seen it mentioned that the forks are spaced further apart on the 98-01's but no one can tell me one way or the other :dry:

Yoshi, any news duder?



I too am interested if you have made a prototype for the 5th gen...

No progress made for a bit. I've been a little busy relocating and my computer has been down for quite a while now. Hopefully once I stop house hopping and get my computer online, i'll be able to make the wood mock-ups and check dimensions. That's if I don't get volunteered for more work over the holidays.

well, after many many months without my computer, finally got it working. I have the first revision of the fork braces done. Still have to fix it up somewhere, as it will not let me make the 3D model and finish it. So here's the outline of what it is going to look like.

[image: Posted Image]

I kept the two piece design. Going to make manufacturing much easier and cheaper. Will use T651 for them. I chose to put the screws on the side instead of the front and back like on the Coerce version because this will leave the front open for attaching a fork seal guard. The curve in the middle should help out structurally. Ideally, it will give the horizontal forces a nice solid face to put pressure on. I may adjust that section a little bit yet, but that is generally how it is going to look. I forgot to add the chamfer where the halves meet and contact the forks.

Once I fix the model, I'll make the few changes I want to and finish the solid model. Not sure what I will use for fork seal guards, but it probably won't be pretty. I still need to get the dimensions for the 5th and 6th gen forks, but I should have them when I go back to cleveland at the end of the month if no one else gives them.

After that, I am going to have a friend laser cut wood templates of the braces and make sure the fitment/alignment/dimensions are all correct. Then it's off to production.

Comment!

oh, and thanks seb for giving me the dimensions from your VTR brace

Hi Yoshi, How thick do you think these will be? (Top to bottom?)
Looks great, any ideas on finish?
:fing02:

[image: View Post]rangemaster, on 09 February 2010 - 11:26 PM, said:

Hi Yoshi, How thick do you think these will be? (Top to bottom?)
Looks great, any ideas on finish?
:fing02:


They are going to be 1/2" thick. No word on finish yet. I would like to get them done with clear annodize, but I need go get the work quoted out to the watercuter first so I can see how much extra I have to play around with. Trying to keep them under $100 for the base version.

[image: View Post]YoshiHNS, on 10 February 2010 - 09:55 AM, said:

[image: View Post]rangemaster, on 09 February 2010 - 11:26 PM, said:

Hi Yoshi, How thick do you think these will be? (Top to bottom?)
Looks great, any ideas on finish?
:fing02:


They are going to be 1/2" thick. No word on finish yet. I would like to get them done with clear annodize, but I need go get the work quoted out to the watercuter first so I can see how much extra I have to play around with. Trying to keep them under $100 for the base version.


Yoshi, if you shoot me the 2D design when you're done, I can do all the waterjet toolpathing for you. I can set all the leads & cutting speeds to where I know you would want them to be. This helps you out 2 ways - 1, you don't pay the programming/engineering fee, and 2, the shop will easily see how long the part takes to cut, for a quote. You can also give them the number of on/off cycles, etc.

Speaking of program files, this reminds me to shoot the other one over to you now... :fing02:

You can sign me up for one, I put one on a old SECA 650 and it made a world of difference.

I'll shoot it over once I fix the problem. Was just going to do the toolpath myself, but not sure if waterjet programming is going to be different than milling.

PRODUCTIVITY!

[image: View Post]YoshiHNS, on 10 February 2010 - 10:51 AM, said:

I'll shoot it over once I fix the problem. Was just going to do the toolpath myself, but not sure if waterjet programming is going to be different than milling.

PRODUCTIVITY!


Depends on the machine. We use Surfcam and CatiaNC for our 5-axis machines, but we use Flow's FlowPath/FlowCut software for the 2-axis and dynamic head machines.

BTW, I would recommend finding a shop with a dynamic head machine(aka corner control) to cut the braces. The mating surfaces in your design need to be cut carefully to ensure proper fitment after WJ cut. The dynamic head/corner control angles the head and nozzle to reduce the kerf angle, or should I say, to keep the cut edge vertical.

Yoshi, please put me down for one bomb proof chunk of billet :biggrin:

Looks sweet, if you PM me w/ where and how to measure the front end, I can give you the dimensions for a 5th gen (and possibly sneak down to the stealership if they have a 6th gen lurking). All for the promise of being a Yoshi Beta-Tester hehehe seriously tho, I just wanna help out any way I can!

[image: View Post]YoshiHNS, on 09 February 2010 - 11:05 PM, said:

I chose to put the screws on the side
The curve in the middle should help out structurally. Ideally, it will give the horizontal forces a nice solid face to put pressure on
Comment!

No screws in the middle section? Keep in mind that the area where you clamp the brace to the fork lowers may not be perfectly round and/or vary a bit in radius. When the surfaces of the center section mate to soon, clamping force will be reduced and not very well distributed over the fork lowers. If on the other hand there remains a small gap, there is less surface area to transfer the horizontal forces.

OK. I'm in. What's another hundred bucks when you're nearly broke. This is much more important to spend money on than mere food. After all, you just rent the food temporarily. The brace will be yours forever. Let me know when and how to pay you. Thanks!

[image: View Post]V4 Rosso, on 11 February 2010 - 08:46 AM, said:

[image: View Post]YoshiHNS, on 09 February 2010 - 11:05 PM, said:

I chose to put the screws on the side
The curve in the middle should help out structurally. Ideally, it will give the horizontal forces a nice solid face to put pressure on
Comment!

No screws in the middle section? Keep in mind that the area where you clamp the brace to the fork lowers may not be perfectly round and/or vary a bit in radius. When the surfaces of the center section mate to soon, clamping force will be reduced and not very well distributed over the fork lowers. If on the other hand there remains a small gap, there is less surface area to transfer the horizontal forces.


I'm not too worried ATM about the big radius in the center. Watercutting should give a pretty good fit, and if not, we'll be able to machine them back into spec when we drill and tap the holes. If I find that the brace is not holding onto the forks well enough then that can be adjusted to accept a thin washer. Once I get the solid model, I can run an ANSYS analysis on it and make sure that there aren't going to be any problem areas.

[image: View Post]YoshiHNS, on 11 February 2010 - 09:56 AM, said:

I'm not too worried ATM about the big radius in the center. Watercutting should give a pretty good fit,

I am not worried about the machined radii either, more about the radius (size) and roundness of the fork lowers and how that affects the brace when installed.

One thought my dad had was that by having no buffer, it would force the tube to become round if it was slighly oval. However, that theory probably won't work where the brace is actually going to go. I'll keep that in mind and pay attention to that when I make the wood mock-ups.

I may be interested depending on where you settle on the price.

Just dragging this post back from the dead, to see if Yoshi has made any progress (he types hopefully)??

Also, I figured out that 3/4 gen fork braces will not fit the 5th gen. The 5th gen tubes are roughly 1/2" wider in the triples. BOOO! But that means that Yoshi is now the man for the 98-01's!!

I know this has been dragging for some time, and I apologize. BUT --- Drawings are done. I email them out tomorrow morning to the watercutters for a quote, and sent it out to a buddy of mine so he can lasercut the wood prototypes. Results should be coming in soon.

[image: View Post]YoshiHNS, on 18 April 2010 - 07:22 PM, said:

I know this has been dragging for some time, and I apologize. BUT --- Drawings are done. I email them out tomorrow morning to the watercutters for a quote, and sent it out to a buddy of mine so he can lasercut the wood prototypes. Results should be coming in soon.


No apology neccesary, I'm sure you're working on this in the limited spare time you possess! I'm just terribly impatient haha

Prototypes!! :cheerleader:

Hi, we made now a new fork brace for 6th gen. VFR, CNC machined soon available for order or group buys at www.motobay.gr
take a look hear

Under $100 Gen5 and I'm in -as long as it isn't clunky or huge looking. Some of your prototypes look awesome.

*sigh* CAD file incompatabilities and problems. I tell ya. The first person who makes a good file converter between CAD programs that WORKS will never have to worry about $$$, ever, or their children.

[image: View Post]YoshiHNS, on 24 April 2010 - 11:13 AM, said:

*sigh* CAD file incompatabilities and problems. I tell ya. The first person who makes a good file converter between CAD programs that WORKS will never have to worry about $$$, ever, or their children.


I'll trade you a file conversion service for the Qatar GP on a USB stick... :rolleyes:

(inside joke boys)

I just got back from a six day trip with lots of hard, fast cornering. I finally pushed the bike hard enough that the flex-related shortcomings of the forks became apparent. I've got some weird wear patterns that look more like scuffs out on the sides of the front tire tread that I suspect are the result.

I don't care what the brace costs - I'M IN!!