Just made an impulse purchase on a retro Cannondale M500 CAD2. It is all built up with modern components…..except the rear brake is a v brake. Front brake is a shimano hydrolic disc so was thinking the same would be nice on the back.

Anyone made their own or could recommend an off the shelf adapter to convert the rear to disc?

A2Z do one and I have one specifically designed to work with sliding drop outs. Depends on the drop out design as to what fits, tbh.

They’re all a bit of a faff, tbh.

I’ve got one of the A2Z adapters somewhere. Bought it for a slot drop out frame which I didn’t build up in the end.

This is the one: http://www.wiggle.co.uk/a2z-universal-disc-mount/

A2Z worked for me though as above it needs the right sort of frame design to work well or fit at all.

I fitted the a2z on my 2000 klein.
Lots of cutting and filing, a bit of welding by a friend to strengthen up the outside plate. (He filled a drilled out hole to make the bracket stronger as I cut off a fixing)
Even with rear facing dropouts it worked.
If your handy it is possible if it douse not fit out of the box.

All depends how much you want discs.

The a2z one works well if your frame has a nice big drop out, the alternative is the onza / rock and roll converter like this http://www.retrobike.co.uk/forum/viewtopic.php?t=151430

I’ve got one on a steel kona as the drop out is too small for the a2z to fit on. Rock and roll bike don’t seem to be listing it at the moment so there is a chance it’s no longer available unfortunately

Out of the two I prefer the onza for function, the a2z for looks.

If its got the old school Cannondale cantilevered drop outs you might find that it limits your options a bit.

Something like the old Hope torque arm set up might work, but you would a) have an old brake, and b) need an old Hope hub. (But I have a bunch of those bits about to go on ebay)

I think someone did a similar universal adapter with a torque arm, but can’t find a link, and probably impossible to get these days. [Edit, like that one up there ^]

http://www.rocknrollbikes.com/trials/brakes/brake-parts/tensile-disc-brake-converter.html

Seems to have changed name from Onza.

Any spare cutlery in the house?

Here is the one i mentioned above (linked above by warcow) on a 95 kona AA. I’ve tried the A2Z on this frame also but found this one worked better as the A2Z kept binding.

BETD used to make one for GT frames. I suppose they could be used on other frames too. As above though, the dropout area needs to be flat and square on to the wheel for it to work.
As a note, the frame needs to be drilled to accept this but then that means no faffing about when changing wheels.

Should have mentioned about the drilling of the frame for this mount, I decided to drill the mount to match the rack mount on the dropout. If you look closely at the above photo you’ll see 2 holes in the mint just above the QR. The larger One is the original one in the mount, the second smaller one is the one I added . In the photo the bolt is missing, but I just use a standard m4 cap head.

This is the dropout on my M500 frame.

andyl if yours is spare and you think it would suite i would be interested in buying it off you.

Thanks to all for the advise, any other suggestions now i have a picture posted would be welcome.

Pretty sure the a2z won’t fit that frame I’m afraid

Shameless poach here,

but if the OP doesn’t want the A2Z adaptor or it doesn’t fit can I call 2nd dibbs to try on my old kona?

email in profile…

If it’s a steel kona it won’t fit either

I would second the view on the cannondale / A2z interface. Unlikely to fit I would guess based on my attempted to fit but unused A2z and a similarly shaped drop out on my Schwinn of the same era.

Edited to remove pointless waffle.

Did anyone ever figure out how to adapt one of these A2Z thingies to fit a Specialized M2 Stumpy? Me v-brake honks like a goose sculpted out of Vieux Boulogne*.

* It’s a very smelly cheese.

If it’s a steel kona it won’t fit either

Is that definitive?
I’m not averse to additional bodging, but I’m not keen to spend £25 on one of these if I’m likely to start chopping it up to fit…

I think so, with some pretty major mods you might get it to fit but I doubt you’d ever get it to fit tightly enough to work properly.

The rock and roll one I mentioned above does fit fine on a steel kona and that’s why I bought it originally.

This is the best PIC I’ve got on my phone that shows the rock and roll/ onza adapter on a steel kona (94 lava dome )

“Did anyone ever figure out how to adapt one of these A2Z thingies to fit a Specialized M2 Stumpy?”
couldn’t fit to a 2001 (i think) M4.
Try and hunt down a spesh mount, or RnR

Front brake is a shimano hydrolic disc so was thinking the same would be nice on the back.

Will it actually make much difference? On Teen1’s old Marin, I fitted a BB7 front and left the XT V rear. He could still lock the back wheel on descents at will.

Unless wheel choice is becoming an issue, I wouldn’t bother.

I’ve got a ’95 Kilauea (that I still sometimes use in Greece) and I just fitted a BB7 brake on the front and an Avid Arch Rival on the back. With SD7 levers you can fine-tune the pull to get a similar feel front and rear.
Works well enough for me.