DIY Carbon brake mounts mkIII - THE FUTURE IS HEAR (flame-a-geddon content)

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DIY Carbon brake mounts mkIII - THE FUTURE IS HEAR (flame-a-geddon content)

42 posts & 29 voices | Started 8 months ago by cynic-al | Latest reply from toys19

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cynic-al - Member

mkII is still stopping fine, so I've upped the stakes in disc-mount technology - lighter than ever before, prototype is now running on some old Trek jump forks (I suspect the braking forces generated would rip apart a normal fork) n newly built rat-bike (Frankenbike is , for the time being, no more).

IMAG0762.jpg by alan cole, on Flickr

Core: balsa wood.
Caliper mounts: metal inserts.
Shell: carbon fibre (no frikkin idea what type)

Soon to be tested - would you like a video? I'm expecting it to break TBH.

Posted 8 months ago #
Junkyard - Member

looks nice and yes to video
as you know my main issue has always been that you are a complete and utter ****will it snap off

Posted 8 months ago #
binners - Member

I suspect this isn't going to end well. Al - if you die in the inevitable accident, can I have your platform bed?

Posted 8 months ago #
piedi di formaggio - Member

Can't you up the stakes and go straight in with hydros and a 203 disc?

Posted 8 months ago #
paulrockliffe - Member

Is there not a reason why all other 'manufacturers' put the mount on the back of the fork leg rather than the front?

Posted 8 months ago #
Barney_McGrew - Member

Pardon?

Posted 8 months ago #
jumpupanddown - Member

pleas dont use this, you will get badly hurt

Posted 8 months ago #
binners - Member

Is there not a reason why all other 'manufacturers' put the mount on the back of the fork leg rather than the front?

Because they're all just idiots, and clearly WRONG!! Whereas Al is right?

Posted 8 months ago #
jeffcapeshop - Member

ok.. what is the aim? other than fun dicking about with carbon fibre

Posted 8 months ago #
Stoner - Member

Is there not a reason why all other 'manufacturers' put the mount on the back of the fork leg rather than the front?

isnt it to do with forward facing drop outs making wheel removal difficult if you have the calliper in front of the leg? Those forks look like they have vertical dropouts so less of a problem, no?

Surely for a bodge it makes more sense to have the forces in compression and use the mechanical strength of the lower to keep things in the right place, rather than rely on Al's carbon fondue in extension to do the work?

Posted 8 months ago #
jumpupanddown - Member

ok.. what is the aim? other than fun dicking about with carbon fibre

He must like hospitals

Posted 8 months ago #
cookeaa - Member

Surely for a bodge it makes more sense to have the forces in compression and use the mechanical strength of the lower to keep things in the right place, rather than rely on Al's carbon fondue in extension to do the work?

I would agree if this was a welded on bit of Steel or Aluminium, but seeing as its a fibre reinforcement which will perform best in tension the reverse mounting actually makes sense, plus the wrap around construction should actually distribute the loads across a greater area of the fork leg... it is completely sound engineering... ish.

Posted 8 months ago #
piedi di formaggio - Member

Of course, you're all assuming he's got the forks on the right way round!

Posted 8 months ago #
AlexSimon - Member

I really like the fact you've used balsa wood.
I also really like the fact you've put the caliper on the front of the right-hand leg.
If it had been me, I'd have been tempted to wrap that post mount adapter into the carbon - I don't like the look of adapters.

I guess if you're expecting it to fail and it does, nothing lost and it proves your gut was right.
However, if you think you've built if weak and it's fine, then that's quite interesting. I hope that's what happens tbh.

Posted 8 months ago #
jumpupanddown - Member

what happens when it gets to hot?

Posted 8 months ago #
CaptainFlashheart - Member

Hear/Here

Posted 8 months ago #
schmiken - Member

Am I the only one worried that he's used balsa wood?

Posted 8 months ago #
andyl - Member

so this is on the forks...I may be missing a previous discussion why not just buy a fork with disc mounts? I can see the point in modifying a frame but a fork? The disc also needs to be rotated but as it's centre-lock you cant.

re Balsa wood - no not worried at all. Really stiff material and it's there as a core like you would use a rigid form.

Posted 8 months ago #
Barney_McGrew - Member

CaptainFlashheart - Member
Hear/Here

Pardon?

Posted 8 months ago #
cynic-al - Member

Mount on RHS - uses carbon in compression, stops wheel wanting to jump out of dropouts (see cheap QR).

"Why?" - I say "why not"? Saves £££, is fun, is a learning process. Of course there are always those that don't get it.

http://www.youtube.com/watch?v=OS8iTEJ2hLg

Sadly they're not too powerful so I may well die, but they've not ripped the mount off yet. I think I'll whap some more carbon on to be safe though.

Posted 8 months ago #
jeffcapeshop - Member

oh i never thought about it being for a fork with no mounts.. i r moron

Posted 8 months ago #
andrewh - Member

Is there not a reason why all other 'manufacturers' put the mount on the back of the fork leg rather than the front?

google images pic, not mine

At least one other adapter manufacturer has tried it the other way.

Posted 8 months ago #
clubber - Member

I had that Hope mechanical!

schmiken - Member
Am I the only one worried that he's used balsa wood?

Balsa is great actually for this kind of hobby CF use - it's not there for strength but purely to provide something solid to wrap/fix the carbon fibre to - you could make a cf tube in the same way - wrap cf around a balsa cylinder. Similar methods use wax which is then melted out once the form is solid.

Posted 8 months ago #
AlasdairMc - Member

paulrockliffe - Member
Is there not a reason why all other 'manufacturers' put the mount on the back of the fork leg rather than the front?

Cotic do that, and there was a detailed article on their site a while back as to why.

Posted 8 months ago #
muppetWrangler - Member

I ripped the p!ss on the spoon mount and the cargo bike thing still invokes mild terror whenever I see it credit where it's due that is starting to look none too shabby.

Nothing wrong with a balsa wood core, I assume it's only there to give you a solid shape to wrap.

The only obvious reason I can see for putting the mount on the back is that it transfers the braking force into the fork rather than trying to pull away from it. It's a layman's explanation so it may well have a more sound engineering principal behind it.

Posted 8 months ago #
Herman Shake - Member

You've got a full face helmet right?

Posted 8 months ago #
Mike_D - Member

Mount on RHS - uses carbon in compression

Which bit's in compression?

Posted 8 months ago #
dirtygirlonabike - Member

Yes to the video. I should have asked you to build me a bike instead of trying to make my new one fit me!

Can you leave me your flat please if it all goes wrong?

Posted 8 months ago #
cynic-al - Member

video:

http://www.youtube.com/watch?v=OS8iTEJ2hLg

Posted 8 months ago #
jeffcapeshop - Member

I KNOW WHERE YOU LIVE

Posted 8 months ago #
filthybloke - Member

Just because it might work in a one off test ride, does not make it a sound bit of engineering.

Every braking action will stress the joint, potentially weakening it, how it fares over time is the key... and with each ride your confidence in it will (inadvisedly) increase and you'll be getting faster and putting bigger loads through it... I hope it doesn't break at that time.

Good luck!!!

ps. Next engineering project... a contraption to hold the bike static, spin the wheel very fast, and apply brake repeatedly... run in the garage until it breaks or 5 years has past.

Posted 8 months ago #
singlespeedstu - Member

OMG you're curb hopping skillzz iz awsum innit.

Posted 8 months ago #
epicyclo - Member

Great idea.

Posted 8 months ago #
camo16 - Member

Well I, for one, am impressed.

Posted 8 months ago #
cynic-al - Member

stu - video of you hopping a kerb please?: I'll post up the rat-bike hanging upside down from a bale of hay or whatever crap you think is artistic at the moment.

Filthy - I know. Makes life exciting

Posted 8 months ago #