Anyone ever done a DIY drop bolt?
 

So my frankenbike is coming along nicely. A Motobecane Fly MTB frame with a steel cyclocross fork and 700c wheels. Front brake is linear pull.

The rear brake is where I'm running into problems. I would like to run a standard road caliper there (since I already have one). I've read some about making a drop bolt that hooks to the arch just above the rear tire. I only need to be able to the drop the brake down about 3/8".

Please share your experiences. Photos would be greatly appreciated.

I made one from about $2 worth of Home Depot parts. Did have a little drilling and cutting work. This is nothing fancy, mind you, just functional. Works with a nutted mount brake. You'll need:
A metal strap - predrilled in the right places if you're lucky, I had to drill 2 holes
A bolt of proper length and diameter to connect this contraption through the brake bridge hole.
A nylon or metal bushing the same width as your brake bridge. I used nylon so cutting it to length was easy. You'll want the hole in the bushing to be just large enough for your brake pivot bolt.
Since you want a 3/8" drop, drill or make sure your strap holes are 3/8" apart.
Cut the strap in two (if you made it from one piece) and file any sharp edges.
Bolt one strap on front and one on back of the brake bridge. Hang the other holes down.
Insert your brake through the lower strap hole, the bushing, and the other lower strap hole. Tighten it all up.
Ugly but functional. Sorry no pic. The bike has been sold.

Seems the easiest option, esp. if it's an older bike, is using old reflector mounts, cutting away the excess and drilling a couple holes. Of course you'd want to double the mount (front and back), and stiffen up the gap between. For that, you could use one or two longer axle spacers, like the kind used for multi-speed freewheels.

That'd all fit in w/ your frankenbike look quite nicely.

Post pics when you're done!

Sheldon speaks from beyond the grave:
http://www.sheldonbrown.com/home-drop.html

I looked at this when I was thinking of modernising an R20. One thing I didn't understand was how Sheldon's example stopped side to side movement of the brake?

I made one from a piece of electrical conduit: http://www.os2.dhs.org/gallery/main.php?g2_itemId=11046

Mine looked a lot like that

I never noticed any problems. Lined up correctly and tightened down it doesn't seem to be an issue, particularly in a rear brake application.

Unless your wheel is severely out of dish or has lots of sideways-wobble, there wouldn't be any net lateral forces on the brake-caliper.

Brilliant. I wouldn't have thought of that.

All these ideas give me some inspiration. I think I could actually pull this off. Thanks everyone.

I'll have to post a pic when it's completed. Don't hold your breath waiting, it could take me a while.

Tektro makes a dual pivot calipers up to 73mm reach that will work. Retails for $20. Not worth the time making your own hack solution.