Author Topic: My floating disc brake system (Read 4094 times)

Simon · « **on:** November 04, 2004, 04:57:54 am »

Just finished building up my custom floating disc brake system,I always thought I could carryout this conversion on my 4500 and reduce brake jack and improve suspension action whilst braking.

The systems relies on a machined boss welded into the dropout,on this is a custom (hand made) caliper mount pivoting on a press fitted sealed bearing and another sealed bearing for the torsion rod also press fitted into the mount,both bearings are rated for both radial and lateral loads,a custom made torsion rod (19mm box section) secured with a Ti bolt through the mount bearing,the rod end is both threaded plus a dome nut fitted,the other end has a thread in the centre for a rose joint to be threaded into,the rose joint fits over an extra long top shock bolt also secured with a dome nut and Ti washers (aerospace quality Ti bolt used).

If this system turns out to be safe [smiley=worry.gif]and reliable I intend to change the torsion rod to a less boxy apperance (19mm box section was the most cost effective I could find),
This system also allows you to remove the wheel without the caliper or mounting becoming detached,the only thing is you have to remove the skewer to allow the wheel to be removed,I've also had to use a skewer 10mm longer (hope) than standard (supplied by Sprucey,www.ukbikestore.com),thanks also has to go to carbonangus for his incouragement and shovelon also for casting an experts eye over the origional design,

I would very much appreciate any comments/suggestion either possitive or negative,I have yet to try it, could turn out to be rubbish,the aluminium welder has advised me to wait a month before using it in anger this gives the weld time to harden, could be forced on by heat treatment but thats a bit of a specialist job.Almost forgot to mention it all weighs in at less than 200g and if you take off the weight of my old disc adapter and the steel shock bolt I've only added around 150g,I shouldn't have much trouble getting the weight back to where it was.
Simon

Will · « **Reply #1 on:** November 04, 2004, 07:22:20 am »

Very clever indeed - and sweetly executed.

Have you done some "static testing" to see if the calipers twist under pressure? I'll be interested to hear how it rides.

Not too sure about the metalurgical basis for waiting a month... perhaps he only provides a 30 day warranty? ;-)

Are you a machinist or just a perfectionist? That's a good looking linkage.

TTFN

Simon · « **Reply #2 on:** November 04, 2004, 08:17:28 am »

Quote

Have you done some "static testing" to see if the calipers twist under pressure? I'll be interested to hear how it rides.

Are you a machinist or just a perfectionist? That's a good looking linkage.

TTFN

Only tried it around the block,yes there is some twisting of the mounting plate,I expected this and just hope I've built in enough strength,my old aluminium mounting bracket used to twist and that was substantialy thinner but never broke,first impressions it didn't jack up so thats a good thing.
Not a machinist just trying to be a perfectionist [smiley=beer.gif] [smiley=beer.gif]
Simon

numbnuts · « **Reply #3 on:** November 05, 2004, 01:14:45 am »

I always liked the idea of floating brakes but think they look crap ! Yours is the most aesthetically pleasing one I've seen, I hope it works as well as it looks!

kiwi · « **Reply #4 on:** November 12, 2004, 07:30:37 pm »

On my old motorcycle dirt bikes the torsion rod or tourque rod was mounted under the swigarm ,looked tidier and the arm worked in tension,therfore doesnt have to be so big,

Simon · « **Reply #5 on:** November 12, 2004, 11:48:32 pm »

Quote

On my old motorcycle dirt bikes the torsion rod or tourque rod was mounted under the swigarm ,looked tidier and the arm worked in tension,therfore doesnt have to be so big,

Absolutely all my MX bikes pre disc brakes had that system (full floating drum brake),
my first idea was to run a torque arm under the s/arm and anchoring 1 end at the s/arm pivot and having the caliper arm facing down and leaving the caliper in its current location,,
I made a mock up and it looked good but unfortunatly it simply didn't work,the caliper barely moved around the disc radius,even trying various lenght arms,I would of liked to of attempted to anchor at the B/B but I couldn't think of a suitable way of doing it,thus I was left with the only option I felt I was capable/competent of carrying out,
Simon.

shovelon · « **Reply #6 on:** November 13, 2004, 04:42:17 am »

Simon,

Your system is gorgeous! Just to rack your brain, I had a thought.

If you route the upper strut mount to inside the shock plates, then you will have a stiffer cross section to stabilize side to side movement. Of course what to do with the shock? Remove it and install a shorter/more common shock that will mount on the strut itself, in line with the swingarm shock mount. This way both upper mounts will stabilize the strut and you will have a nifty shock adapter as well,because the adapter will be semi-locked to the disk brake. The almighty piggyback system.

Did I do a good job of racking your brain?

Terry

Simon · « **Reply #7 on:** November 13, 2004, 05:12:35 am »

Brilliant idea,I really like that one, [smiley=nod.gif]
I'm sure a shorter shock with the same stroke could be obtained,may require the torsion rod to have a small dog leg in it to clear the tyre but that shouldn't be a problem,
infact my risse shock nearly has enough clearance on the inside to mount the strut as it stands,
I will be giving your suggestion a lot of thought in the future I'm sure a really nice mount could be manufactured,hey maybe even have multiple mounting holes to enable different travel/head angles to be obtained,winter project (he he).
Anyway had a little go on the bike today performed excellent just waiting for better weather to give it a proper test.
I am currently redesigning the pivot as the precision bearing has more twist flex than I expected,don't get me wrong it performed fine but I'm concerned about longevity,
so this week I'm replacing the 7mm wide bearing with a 12mm wide needle roller bearing on a custom inner bearing race that won't allow any twist,each end will be sealed with a O ring that will allow a little bit of caliper self alinement,
also I might of sorced some aluminium I section for the torsion rod, when/if I do fit this I'm also going to fit the sealed bearing at the shock mounting end as I first origionally intended to do instead of the rose joint,
anyway keep em comin [smiley=nod.gif]
Simon

kiwi · « **Reply #8 on:** November 13, 2004, 09:07:43 am »

ahhh yes come to think of it they were drum brake bikes...in my minds eye the torsion rod goes straight to the crank spindle.I guess its to close to the swigarm pivot.I remember the motorcycle swingarm pivot was quite high and the torsion rod was mounted right at the bottom of the frame cradle.The swingarm itself and the torsion rod di not converge as it would if you tried to mount this system on the carbon.The system that you and terry are discussing is like rdi ltk system for world cup bikes

Simon · « **Reply #9 on:** November 13, 2004, 09:43:47 am »

Kiwi,quite right,
as for the RDI LTK system I've not seen this though Callum did contact me through topica (he liked the floating brake system idea) he did mention the LTK suspension system,I've tried looking it up on the 855 web site but the pic's are unavailable,I've asked for a pic as I would be interested in seeing what they did, though I believe its an increase in suspension travel not a floating disc system,if anyone has a pic I would be very gratefull if they could post it or email it to me,
Simon.

kiwi · « **Reply #10 on:** November 13, 2004, 12:17:05 pm »

the ltk is a linkage system that the strut on a world cup bolted to give extra travel.

the link is alive here

Simon · « **Reply #11 on:** November 13, 2004, 08:54:15 pm »

Thanks Kiwi,dunno why I couldn't find it,
looks a good idea,though does it raise the b/b height,suppose that wouldn't matter as a d/h freeride application that its aimed at,
I don't think shovelon's idea (if I'm correct in understanding his system) has to many similarities certainly in looks with the LTK system but they may have similar principles in operation,I think when he means a strut that the shock is attached to, I think its more of a piggy back bracket on or part of the strut/torsion rod with the shocks top mounting attached below it, so the floating caliper torsion rod is above it secured in line with the origional top mounting bolt,the whole thing is secured using the origional top shock mount,as the new shock mount will be lower thus the requirement for a shorter shock i2i,the lower shock mount stays the same direct onto the s/arm,this is unlike the LTK system as the shock isn't activated via a strut but direct from the s/arm as standard just mounted a bit lower,but maybe you would gain extra travel when the torsion rod moves inline with the s/arm having the shock mounted to it,I hope I understand his system correctly.
Simon
P.s Terry how about a sketch of your system to make things clear [smiley=nod.gif]

shovelon · « **Reply #12 on:** November 14, 2004, 04:26:17 am »

OK,

I will sketch and have junior scan it up into the infernal reaches cyberdom.
Give us a couple of days.

It's off to try the rebuilt Stratos cartridge.
Wish me luck!

Terry

loaded · « **Reply #13 on:** November 14, 2004, 08:17:37 am »

Hey, I have a chance of getting my hands back on my old proflex 955 world cup & am thinking it would look mighty fine with this long travel kit on the back!!! Especially if it's all shiny silver like!!

Is anyone on the forum running one of these kits??? I presume as they fit an x56 I could put one on an 955 with no real problems. Or maybe I could try & make my own, they look like a relativly simple idea it would probably be cheaper with the current AUD vs GBP exchange rate!!!

Cheers,
[smiley=beer.gif]
luke

kiwi · « **Reply #14 on:** November 14, 2004, 02:49:34 pm »

sheesh simon ...its similar enough for me mate..its a metal "linkage" that mounts to the swingarm and original shock mount

serously tho your system looks awesome. Congratulations on a good design and build proect,I am envious of ypur skills!

News:

Menu

Picture Bit

Author Topic: My floating disc brake system (Read 4094 times)

Will