Forum menu
Hard to comment without seeing the dropout and mounting points in detail. However, my old M2 Stumpjumper uses the following Specialized designed and manufactured disc brake adapter which bolts to the V-brake mount and uses a single M6 bolt at the dropout. It works perfectly.
[url= http://farm6.static.flickr.com/5223/5553925215_ffdcc45178_z.jp g" target="_blank">
Note that it does have a significant curve to it so the brake lines up but then reaches the V-brake mount.
[url= http://farm6.static.flickr.com/5266/5554511172_2018d55a6f_z.jp g" target="_blank">
I'd definitely go for something like this rather than relying on epoxy. Also easier to remove later.
You describe the rack mounts as being in 5mm Ti plate dropouts? I'd have thought that the two bolts would be perfectly adequate, based on how this one mounts to my Stumpjumper.
Epi I have all the parts (includign a built wheel) and the weight must be lower - 350gm hub leaves 600gm for caliper and mount.
Thanks AdamM, first-hand constructive comment at last, I'd forgotten about those mounts, seems to me too that 2 x M5 =ish M6 in strength termss.
TJ you could learn a lot from this guy! 😛
Surely regardless of being able to mount a disc mount, the rear axle spacing would be wrong for a disc hub?
That's as sure as the fact that metals can flex.
al, happy to chat more about details off line if you like.
adammonline AT gmail DOT com
There are a couple of other pics on my Flickr site (click on either of the ones above) including a close up of the dropout.
Cynic-al, that specialized one Adam-M posted is just (an official version) of the one on the other page, and the ones i linked to on MTBR, infact, its exactly what everyone has been suggesting 😀
Obviously tho that one wont fit as your canti-post will be higher up, and hence increase your rotor size rather than reduce it, so youll have to make your own, like er... the one on the other page 😆
What about the Quad mount below? ONLY works with cup and cone hubs though, as long as the dropoouts are near horizontal then it works, fitted a few in the workshop.*
[img] 
[/img]
*I CBA to read the whole thread so sorry if it's already been mentioned.
Or [url= http://www.allterraincycles.co.uk/product/118257.html ]THIS[/url] one from A to Z?
[img] 
[/img]
This sounds like a pretty bad idea.
Give it a bash though, the results might prove amusing.
Quad looks interesting, a2z is gopping.
STATO no canti mounts on frame.
I know someone that made a mount as you suggest, for a Ti road bike..err...what was it...Airborne Zepplin IIRC. He just filed and drilled a piece of plate steel and bolted it to the rack mounts, no mucking about with epoxy. Worked fine as far as I know. Think he only ran a pretty small rotor.
I'd go with one of the adapters that are available though, I've used an A2Z for 4 years on an old frame, they work great.
I sprayed the A2Z to match the frame....had mates that saw the bike regularly that didn't realsie it was an adapter for years.
Hmm, any pictures of that Quad mount fitted?
I think I can see how it fits together, but a visual would be nice 🙂
Can't work out why cup and cone bearings would be required, though...
Aidy - you can't see the back - there's a hexagonal cut out that fits over the nut on a cup and cone hub to help stop the whole thing rotating under braking forces and to make sure it aligns with the disk.
Mama dirt has some pics of one fitted somewhere.
Cynic-al - I bought a quad for a frame butI ended up not really runnign with disks so it was fitted and then not ridden - £10 posted?
[edit] - I did find it a tight fit in the frame as it makes the hub a bit 'wider' due to the depth of the bracket etc - I ended up removing a spacer from the hub (XT) to help.
I've fitted the a2z to an old Kona. Looks great, hard to spot once actually on the bike. The bike has been my commuter for so many years the adaptor is now a little rusty, and it's not impacted the stays in any way.
That dogbone thing, and the one on the spesh, look absolutely horrific and must weigh something ridiculous.
The Specialized bracket isn't the most attractive item, I'll grant you that, but it is designed for the frame so fits and works well. Cheaper than a new frame too. Doesn't weigh much at all, to be honest, and a much tidier fit that either of the adapters shown above (mine is at least attached to the frame so doesn't come off with the wheel).
thanks wwaswas but I'll try my own first.
I need to ride the bikes a bit first, I suspect the ti frame may be a bit stiffer than I'd like off road, though it might make a great tourer.
I think the SBC bracket looks really neat.
I've got the spesh one on one bike. It works really well. Once fitted there is no extra faff changing the wheel, as simple as a proper welded mount. Mine is bodged onto a frame not designed for it BTW. I'd go for something similar if I were you as it spreads to loading.
This works by bolting to the 2 threaded holes in the Ti plate dropouts. Its not braced against the seat or chainstay in any way. It is relieved to fit around the dropout.
[url= http://www.shopatron.com/products/productdetail/part_number=FG-ACC-DISC-001-L/615.1.1.1.27021.0.0.0.0 ]picture.[/url]
I have actually done what you are sugesting.
My Proflex came with Magura rim brakes which were good in the dry but made good mud collectors in the wet.
Initially tried a 3mm ally plate , shaped like the A2Z adapter to fit around the drop out. I then drilled and tapped 4 holes into the drop out ( ally approx 12mm deep ) to take 4 M4 bolts.
The caliper adapter then bolted onto the ally plate . This then bent offline and was replaced with a steel plate .
The steel plate was drilled to take all the same fittings , and also was epoxied at the same time .
This has been on my bike for about 2 years and works very well .
Avid Juicy Ultimates with a 160mm rear disk. I have to check the mounting bolts everyso often but to all intents and purposes its fit and forget.
The bike gets ridden most weekends and has done hundreds of miles with the mod in place.
Here's a couple of drawings of how it might look, in white: original idea, in green: one located on the hub-axle.
[url= http://farm6.static.flickr.com/5182/5573810126_2cf688488a.jp g" target="_blank">
[url= http://www.flickr.com/photos/7693620@N05/5573810126/ ]IMAG0397[1][/url] by [url= http://www.flickr.com/people/7693620@N05/ ]alan cole[/url], on Flickr
Should I take the silence to mean that my idea is not actually as guff as many of you were saying originally?
cant see flickr from 'ere.
Will taunt and criticise when I get home.
White adaptor failure mode: seat stay brace flexes, upper eyelet acts as pivot, lower pivot ripped off.
Green adaptor failure mode: seat tube deforms over time.
Just playing devil's advocate - it could work.
Responses have varioed through "It won't work why ask this again" (guess who) to "4 m4 bolts is all you need".
I suspect no one can answer with any authority.
seat tube deforms over time.
Blimey, it it telekinetic? 😛
Anyway in the white one I'd not bolt it securely to the upper mount.
Well I did it...with the bare minimum of cutting just now, so it looks a little bulky (takes frikkin ages with a 12" hacksaw). Seems to work though and only moves a little under braking. Hope to finish it off and glue with a little carbon wrap this week.
[url= http://farm6.static.flickr.com/5187/5609376354_a869c02d52.jp g" target="_blank">
[url= http://www.flickr.com/photos/7693620@N05/5609376354/ ]IMAG0433[/url] by [url= http://www.flickr.com/people/7693620@N05/ ]alan cole[/url], on Flickr
You need someone to cast an eye over it Al. Check the stress colours....
I think a proper "see-er" can just feel th stress aura without having to look 😛
I can't make head nor tail of that. Did you weld on a load of extra tubes?
Sorry the rack is obscuring it. I've made up a plate as per the white drawing above.
Oh right, with the two triangles. I got distracted and confused by the rack too.
Looks heavy. How is it joined to the seatstay? Need more pics.
Ah yes I thought the rack was part of it.
It might work...!
It's also a rather large disc for a road bike...
It does work! It just might break. Yeah I could have used a 140 but I had to bodge the 160, which I already had, so I didn't want to buy a new rtor just to bodge it. 160 also gives more distance to caliper for more bracing.
It's bolted on the inside of the dropout at the rack and mudguard mounts.
well sceptics, I did it and it seems pretty solid. If you see my epitaph on stw tomorrow, you'll know what happened.
[url= http://farm6.static.flickr.com/5225/5684516335_64e23d52ac_z.jp g" target="_blank">
[url= 
[/url] by [url= http://www.flickr.com/people/7693620@N05/ ]alan cole[/url], on Flickr