Fork brace question...

[dwilson]

I have some 1/2" aluminum plate, tools and lots of free time...  I want to make a fork brace.  

What shape are the holes?  I assume they're not perfectly round, probably a touch loose somewhere and a little tight where the sides bolt on?  

If you have one and a dial-caliper handy I'd appreciate some measurements  ;D

[tzracer]

When I worked at Buell any part we made that was going to clamp onto something round, it was machined round to the size of the tube. The hole was machined for the clamping bolt(s) and finally the slot was cut.

[dwilson]

So I should try cutting the holes (the same size as where I'll be mounting it), drill the holes for the bolts and then cut the end pieces off?  I'm assuing that the material removed by the cut (1/32" +/-) is enough to supply the grab?

Thank you for the reply.

[tzracer]

That would be how I would try. The contact is friction, so as much contact as possible is needed. That is why the hole should be round and the size of the tube. You may want to make a 3 or 4 piece brace as some manufacturers
(Telefix - http://www.xs11.com/pix/telefix1.jpg) have done.

Cutting the ends off and using 2 clamping bolts would require the holes to be properly spaced or you will introduce stiction in the fork by bending it (inward or outward).

[dwilson]

Thanks, you 'da bomb

[tzracer]

You're welcome. Let me know how it turns out.

[Nate R]

Brian, do you think a fork brace is needed on the SV?  How about with the aftermarket triples like you have?

[cardzilla]

I agree, save your creative juices for something that will make you faster.  Maybe the motor or lightening, etc.  The AMA outlawed fork braces for supersport this year citing the fact that modern sportbike front ends are extremely rigid and don't need them.  The rule was leading to some "liberties" being taken by the bigger teams on what a fork brace was (you know the "creativity" that exists at that level  ;)  Many times throughout the history of GP racing teams have had handling ills that no one could figure out ...  until they softened the frame or one of the ends. I had the same experience in 1993 with a supersport F2.  I couldn't figure out what was wrong... until I removed the fork brace, then everything was smooth as glass.  I've never ridden a SV, but my guess is the brace will do more harm than good.  Remember, stiffening the front end may expose frame flex, which is much worse.  Just my two or three cents worth.  Good luck either way.

[tzracer]

Nate, with the Attack triple clamps I don't think a fork brace is necessary. Of course you really don't know unless you try ;)

In general, a cheap, poorly made brace can make things worse than no brace at all (due to stiction issues). The brace is mainly to keep the fork tubes from twisting relative to each other. It is most noticed on turn in.

[dwilson]

Being into mainly 70's bikes I always think of a fork brace as a good thing  :)  After thinking about it, I'd have to agree it's probably not necessary.  

[Super Dave]

Having raced bikes that were made in the 70's and earlier...

We tried fork braces on a couple of bikes, and didn't have good results.  Ended up taking them off.

It really can come down to rider preference, that's why you didn't see it being used on all the bikes of the teams that were working with the braces in the AMA.