masi61

We all know that modern brakes are better than what was available back in the 1970's for our road bikes that took the nutted mount calipers. If you are like me you would rather not drill into your vintage fork crown to enlarge the hole to accept a recessed nut to permit mounting modern recessed mount brakes. The other day it occurred to me that the answer is actually quite simple if someone would just execute the design.

What I'm thinking is that you could use a short M6 stainless metric bolt and an M6 stainless flat washer into the back of the fork where the bolt usually exits. Here the short bolt would thread into a specialized nut that has flats on it for a small open end wrench. This special nut would be like one of those long nuts that are threaded on both ends for tensioning screen doors and clothes lines. This one would have to be tapped with an M6 tap on each end. My idea might work better if the "front" brake actually was a rear brake since a short brake bolt would give room for the specialty nut to be threaded on inside the fork tube.

Has anybody tried this? I'm no machinist but I do have basic knowledge of cutting threads. I could take some square aluminum bar stock and drill and tap each end to create the specialized nut.
Lately I've been burned on ebay when I buy "complete" caliper sets. One time I got 2 front Dura Ace 7403 calipers, another time I got 2 rear white Gran Compe 400 single pivot sidepulls.

Bianchigirll 

OH I think you just opened a can of worms here. while your idea sounds good I think there will be lost of oppsition to your statement that newer brakes are better. no one changed the basic sidepull for decades so it must have worked. they did not noticable inprove them when they too the same calipers and put the recess mounting bolts on them.

if by modern you mean sidepull I pesonally dislike them.

masi61

Maybe I should just say: "I personally like modern dual pivots better". What I'm trying to get at is: How can you take a rear caliper with a short little brake bolt, thread it onto a nut inside your fork and then take a corresponding hex head metric bolt, thread that into to the back of the fork and into the other side of the same nut? I think it would work.
After trying any number of older brakes on my Puch Marco Polo touring bike (including Gran Compe, Shimano 600 and Weinmann centerpulls), I long for the controlled and powerful braking of the Shimano 105 (1055) single pivot calipers or the Dura Ace 7403 dual pivot calipers. BTW I have purchased a set of Tektros R538 nutted dual pivot brake calipers from Velo Orange for this project but I have yet to install them. I can't tell you how scary descending in the rain on steep hills is with those older brakes with my (very nice) Wolber 58 rims.

John E

I have not done the geometric analysis, but do dual-pivot sidepulls really provide more braking leverage than the older single-pivot designs? There is no magic in a bicycle braking system -- all that matters is the way the handle fits a particular rider's hands, the system leverage, and the coefficient of friction between the pads and the rim. A low-compression cable housing will permit the use of a longer-travel (and therefore higher leverage) system, and aero handles tend to provide about 10% more leverage (and require 10% longer travel) than their older exposed cable forebears.

Otis

Why not just make a new pivot bolt for the caliper? Most modern calipers use pivot bolts that would not swap easily for early nutted style ones but I'm sure you could have a machinist make you one with a longer threaded portion. You might only have to do one as a standard front might work for a rear?

With that said there may be reach issues if you have a 70's frame?

fiataccompli

Doesn't Tektro make modern style dual pivot caliper with longer reach that uses the old style bolts? Thankfully, the two frames I've drilled were not valuable enough to worry about. The amount of material to remove seems pretty minor in terms of strength, but I've not done a detailed mechanical/material analysis...but for a frame worth more than 10 or $20, I'd rather not mess with it too much.....but, then again, I don't worry much about cold-setting rear triangles, so maybe I'm not being consistent.

To reply *on topic* I'd say the theory sounds good. Another approach would be to cut the mounting stud and weld on a longer stud (which would require some grinder clean-up unless you're a helluva welder, of course)

twoducks

They do. When I was getting my winter commuter together I wanted a pair of non-recessed dual pivots. The Tektros were one option I found at the LBS, but I ended up going with some SNGs because they were available long-reach to accommodate my fenders. They have been wonderful.

I looked into drilling out the frame to accept recessed brakes. It didn't cost much, but I decided against it even though the frame is only an old Grand Prix.

mkeller234

Yes, I was going to suggest the nutted Tektro dual pivot calipers as well.

Check it out, nutted with 57mm of reach: https://sheldonbrown.com/harris/brake...ers.html#63-75

fiataccompli

fwiw, I think well-tuned old centerpull Weinmann or DiaCompe brakes work really well, but I get easily annoyed with the suspended cable hanger.

mkeller234

Yeah, I have had good luck with the Weinmann 999's that I am using. I'm not even using new or good pads with them either so that is promising. Maybe some day i'll buy some kool stops and see if they make much of a difference.