new alloy one piece girvin elite disc mount - OP?

[junkster]

Hi people, any criticism is welcome.

One piece alloy bashed to within an inch of it's life  [smiley=nod.gif]

Will be bonded to the alloy leg using JB Weld steel epoxy. The longer curve goes along the inside of the leg, (and the drill holes, aside from lightening it a little), hopefully aid the bonding strength). OP, KIWI, and Tmaybee - do you think it'll be sufficient.

Took your idea OP, using the same 4 1/4" long measurement, but increased the length of curve on the inside. I'll need to make 2 x tab extension/spacers and fit the original alloy postmount adapter I made for my current mount, but what d'ya think? cheers D  [smiley=beer.gif]

[Old Proflexer]

a good idea and i've done similar projects on front and rear.

please keep in mind that the strength of the bond with the leg is not the critical issue as a minimal bond is all that's necessary to keep the part in place.  the issue is applying the pressure from the caliper over an extended area on the leg and that pressure is centered on the leg.  

with that, gum can hold the part in place, the bracket made out of an old campbells soup can and the piece would work well.  (for new readers, see some of the pics of the clampon elt disc mount in my gallery)

make sure that you mount all 'final' hardware, get all the angles, spacers and positioning 100% correct before bonding.  that will allow you to trim off a lot of excess as well.  put it all in place a few times til your happy with the fit then sleep on it.  bond it the next day.  I thought i had it all wired first time around and afterwards realize i still made a few minor miscalculations.  be sure to have all parts assembled and use the wheel pressure to hold the part in place while bonding.  I use some elastic straps to use wheel forward pressure to hold things in place and some big rubberbands on the brake lever to hold the caliper on the rotor.

but in the end, hey, it's just a bike and projects like these are supposed to be individually fun and challenging to us garage mechanic engineering wannabee types -
just go slow - measure twice, cut once so you'll be happy with the end project.  
looks like you're well on your way my friend.

OP

[kiwi]

I agree with OP that the forces should be spread over a large an area as possible and the bonding material plays a role here in that it can fill any minor variations.My only reservation is the bond may be critical those times you dont quite make the top of your favourite tecnical climb and clamp on the brakes just as you start to roll back
The unknown factor is the strength of the crosslink leg itsef.I was amazed at how thin the leg material is the first time i pulled my vector to bits....I have some fears about the strength of the leg.I doubt  it would fail instantly but keep an eye on it.If i ever get around to making one it will encricle the whole leg,and i would try to get some leverage/assistance from the dropout.

[Simon]

Checkout this
http://www.proflex.demon.co.uk/855headfeatures/bike97/index.html  
scroll down to the article on disc brakes.
It appears Hope produced at one time a D shaped disc mount for the girvin fork,this was stopped at the request from Girvin,
Simon.

[dan]

hi all, (couldn't remember my log in and on a mate's PC) - thanks for the input. Will bear all in mind -

Simon - you mentioned a wrap around idea for the girvin mount - that is actually my current design (eyesore):

 [smiley=laughing.gif]

I wanted to rid myself of this design mainly because of the new girvin legs. I decided I'd try OP design, slighly modified. My current one adds way too much weight, (cause it was knocked together and added to, it looks a right mess. Half the problem was the IS to Postmount adapter I had to make. Rather than redesign the mount, (couldn't remove it as bonded to the leg), I added to it. Ideally would like to have stuck to IS design but only had the postmount caliper. Works fine though [smiley=nod.gif]

Also, your reverse direction when rolling backwards warning is duely noted. I usually use the rear brake when rolling backwards anyway. Will most likely create a brace utilising the left v-brake boss as well I think. A brake booster will be emploed too.

A while back another poster warned my not to do the current mod on the girvin vector legs, so I figured the girvin elite were stronger, (the drop outs are much better constructed).

I had looked for the mysterious D adapter from Hope, but there is nothing on the Web. Pity, would\ have liked to look.

I have drilled more small holes in the thiner outer side of the mount to aid the bonding, (heard someone else had done this with their carbon dic mount)

cheers people, will put up a piccy of the finished mod in due course.

Dan  [smiley=beer.gif]

[junkster]

damn, I hate typos you can't amend:

(" heard someone else had done this with their carbon dic  [smiley=laughing.gif] mount ")

heh, heh - carbon dic  [smiley=laughing.gif]

ahem!   [smiley=turtle.gif]

Dan  [smiley=beer.gif]

[will]

Gents,

This string is very helpful as I am trying to cipher a front disc solution myself...

The world cup frame just looks "right" with a crosslink fork. (Don't really like the look - or the physics - of a slider fork. Hard & frequent testing of my 'zoke Flylight is tearing up my headset.)

At the same time, once you've gone with discs, you can't go back!

If there was a way to get the exact cross sectional dimensions, like a print of the extrusion, I could quickly print up an engineering drawing for an adapter.

With a good drawing, I know a guy with an EDM machine who could cut a dozen of these things next weekend...

So, anyone know the dimensions? Those blending radii are a little too tricky to guess at.

Will

[Old Proflexer]

Dan -

I can only imagine you had that stuff all over your hands when you were done -

This one was my prototype -

http://idriders.com/proflex/galleries/Old_Proflexer/Front%20Disc%20Mount%20Crosslink%20Finished%20Side%20Closeup.jpg

OP

Will - who needs dimensions if you're good with a hacksaw and a big hammer? [smiley=laughing.gif]  
(I gotta admit that i did use my "DREMEL!" to touch things up)

[junkster]

Added brace to hold the JB weld epoxy bond, so if the brake should be applied while rolling backwards the bond is held. Around a 3rd of the weight of my previous attempt. Thanks OP for the initial mount concept, and everyone else for their helpful input. Works a treat!  [smiley=nod.gif]
[smiley=beer.gif] Dan

[Old Proflexer]

looks perty -

you be careful out there -

OP

[junkster]

[Old Proflexer]

looks like you remodded the rear plate as well -

somehow it looks familiar - - - - -


OP

[junkster]

sure did a few months back - inspired by your template, but again modified to suit the materials and tools to hand. check out my gallery.

cheers again  [smiley=beer.gif]

D  [smiley=nod.gif]