Fork brace rendering

[olie05]

YG,

Could you please trim the fat on that last post so that it stays on topic? This is not about fat axles or axle swaps. This is about fork braces.

I recognize that the problem is the small diameter axle, but in my approach, that is also a constraint. I will retain the stock axle, so please stop suggesting that I need a larger diameter axle.

[yamaha_george]

YG,

Could you please trim the fat on that last post so that it stays on topic? This is not about fat axles or axle swaps. This is about fork braces.

I recognize that the problem is the small diameter axle, but in my approach, that is also a constraint. I will retain the stock axle, so please stop suggesting that I need a larger diameter axle.

O,

OK I will sum up for you

Fork brace = waste of time/effort/ money
YMMV

[olie05]

I would think that as an engineer you could understand how stiffening the connection between the two fork legs can be accomplished either with a fat axle OR with a fork brace.

Since you don't see it that way, I'll just send you one when I make it and you can tell me if it works or not.

[SquadraCorse]

I put mine on because I have a thing for Italian parts and it looks cool. It's an old bike, if I could ride it to the limit and front end stiffness was holding me back, I'd buy something newer with USD forks. But I can't ride that well. So to me all of it's negligible.

[yamaha_george]

that as an engineer you could understand how stiffening the connection between the two fork legs can be accomplished either with a fat axle OR with a fork brace.

O,
I understand as an engineer that the problems origin is the contact with the road surface and the mass of the bike putting lateral forces thro the rim which being cast is very stiff then thro the axle to the first part of the "frame " ie the forks. This lateral force is magnified by the distance from contact patch to the first thing other than the rim (since the rim absorbs very very little) so by definition has to go thro the axle to the fork legs. on the FZR these are both kinda spindly.

Because any uneveness in the road can help multiply the force significantly we have sprung forks which being hopefully parallel are supposed to work together in fact they do not since the axle the thinest bit around flexes.therefore the shocks do not quite work in harmony.(which is why the whole lot feels like wet string under us )

Now you say that a brace half way up will tie them together, yup sounds feasible except the force by now has multiplied because the distance from the origin has doubled I.E no longer the radius of the wheel but the diameter plus a chunk of clearance. so we are now trying to tie the forks together but we must now cater for what 2.2 times the original force.

That fork brace is usually flat by design rather like a plate which is scientifically easy to twist so not too much help there. the brace needs to be braced to resist the torsion thro it. this is compounded by a means of fixing to the forks which is in itself a weak point.

I would love you to think this thro and find an answer, and come up with something that worked, was simple to make & use, you could not have a bigger fan than me.

I am flattered that you want me to have one of your design I would be churlish to dismiss your efforts out of hand so i will do you a deal make one and send it to me I WILL PAY the shipping and I will fit it and try it out.

be aware that I will PM you my thoughts I will not try to make fun of you publicly if it fail me I will keep your trust that you have shown for my experience in riding.

I do not think I can be fairer than that, but I would first ask you to read the books I mentioned to give your self the better shot on making a better brace I have faith in your trying

[reelrazor]

Yeah, maybe getting a bit off-topic....but fork braces have been done-there are numerous manufactured ones, and as Geo points out, they have dubious benefits.

The old school 'hoop' style fork braces/fender mounts (think chrome fendered early Honda CBs) were actually quite good at doing what they needed to do...bolted low on the fork tubes, up over the tire and were usually paired up fore and aft.



How about drawing up a mechanical/linkage anti-dive setup for our bikes?

I had a TZ350 chassied RD400 engined bike for a while that had linkage anti-dive on one caliper-the other was normal 'fixed' . It felt odd at first but quickly became a nice addition to it's handling.


examples:

http://classicmotorcycles.about.com/od/ ... i-Dive.htm

[DonTZ125]

That anti-dive concept has been flickering in and out of my head since the day, lo these many years ago, that I first saw pic of a Bimota Tesi, with the free-swinging caliper carrier and a tie-rod to the chassis...

[yamaha_george]

That anti-dive concept has been flickering in and out of my head since the day, lo these many years ago, that I first saw pic of a Bimota Tesi, with the free-swinging caliper carrier and a tie-rod to the chassis...

I much preffered the Cork Ballington Kawa design very tidy looking:-

[olie05]

I now have a fork brace on my bike. I went and got some forks and brakes for my bike, and the guy I was buying from had this fork brace sitting in a box. and it was for sale. I jumped at the opportunity.

It looks very similar to this:



It fits snug against the fork legs, and best of all I CAN TELL THE DIFFERENCE.

The front end feels much more solid over road irregularities, and bumps. I'm a believer in fork braces... (I already was, but that was for purely theoretical reasons.)

I don't know how much my design could improve upon what I already have, but I still want to run the simulations and see if there is any benefit in going to my design.