10/31/15 4:02 AM

I'm working on the ~'75 Raleigh Grand Prix mixte bike again. Now it's time to look into brake options.

Is there a good way to attach brakes mounted with allen key nuts to a frame engineered with regular hex nuts?

10/31/15 5:26 AM

...the seat stay bridge and fork crown. The fork should be easy to do with a drill press. The seat stay bridge may require a right-angle drill or a Dremel tool, depending on how much room you have.

Barring that, it may be possible to fit a longer mounting bolt to some models of brakes, but that's probably more of a long shot.

10/31/15 7:14 AM

For the front, enlarge the hole at the rear of the fork crown using a 5/16" or 8 mm drill bit. That will allow the recessed nut to fit. Get a nut of the appropriate length and these are available in a wide variety.

For the rear, it's a bit trickier. One way is to buy a second front brake which will have a longer mounting bolt and attach it with a nut like the OEM brakes.

It is possible to enlarge only the front hole of the brake bridge but the clearance between the bridge and the seat tube is tight so a conventional drill won't fit. I've done it using a short 5/16" drill bit clamped sideways in a Vise-Grip and rotating it a fraction of a turn at a time. It's laborious but not as slow as you think since there is not much metal being removed.

10/31/15 1:43 PM

I've got the 90 degree attachment. This might have legs.

Shucks, these are out of stock.

10/31/15 3:01 PM

Tektro brakes come in a nutted version. e.g.

http://harriscyclery.net/product/tektro-r539-47-57mm-reach-dual-pivot-brake-caliper-front-std.-nutted-version-3079.htm