Bicycle Mechanics - Upgrading Brakes and got stuck

I'll start by saying that I feel ridiculous and defeated. Note: Jump to the bottom if you don't care about the story.
I went to a local bike swap today to get a new helmet or at least see what was there. In the end I determined that buying a used helmet would be stupid but not before I determined that I needed new brakes for my late 80s road bike. I should mention that I've never had any problems stopping on my current set up, so it makes this all the more humiliating. I asked a mechanic at the shop if brakes were universal and he told me that they were for the most part. I don't have an unusual bike, so I got a set of Ultegras for $25 and an obnoxious yellow Tinker Juarez saddle because it was $3 (how can you pass that up). I set off home to install my new brakes. Several hours and a few beers later, I am the proud owner of a late 80s road bike with no brakes and an obnoxious yellow Tinker Juarez saddle. It seemed easy enough...just take the old ones off and put the new ones on. Not so fast. Here are the details.



The Problem (bear with me as my terminology is no good):

The old Dia Compe sidepull brakes have a longer pivot bolt "stem" (the threaded bolt that goes through to the other side of the fork). When I went to put on the new brakes which are dual pivot, the stem wasn't long enough to get the "hex nut" onto the threads of that bolt. I don't know if I'm thinking inside a box or if the brakes simply aren't compatible with my frame. Any insight would be great. Thanks in advance!

The Parts

Frame: I think it's a giant frame, but badged as "Sanwa" again, mid/late 80s maybe.
Current Brakes: Dia Compe N500 http://http://www.velobase.com/ViewSingleComponent.aspx?ID=93b3e36e-5dd1-4178-8430-5225c19ab65a
New Brakes: Shimano Ultegra BR-6500 http://http://www.roadbikereview.com/cat/brakes/brake-calipers/shimano/PRD_28100_2480crx.aspx

You just need a longer recessed nut. Stop by the local LBS and see if they have one.

Hint: Bring the bike to ensure a correct length.

You just need a longer recessed nut. Stop by the local LBS and see if they have one.

Hint: Bring the bike to ensure a correct length.

Actually, there's a bit more to it than that.

He needs to drill out the back side of his fork crown to accept the recessed hex hut. That's the easy part. Figuring whether and how to drill out the front edge of the brake bridge to accept the rear recessed nut is the hard part.

Also, late 80's road bike? I'm not making any bets about brake reach.

i just hope you have 700c wheels for your 700c reach brakes and aren't trying to apply them to 27" wheels. that can be a real pain in the aisse if your caliper slots dont reach down far enough :) but hey, i've seen v-brakes brazed onto a '75 motobecane grand touring so anything is possible.

Actually, there's a bit more to it than that.

He needs to drill out the back side of his fork crown to accept the recessed hex hut. That's the easy part. Figuring whether and how to drill out the front edge of the brake bridge to accept the rear recessed nut is the hard part.

Also, late 80's road bike? I'm not making any bets about brake reach.
Drilling might not be needed, it depends on the fork. I didn't need to drill my fork crown for my '85 Trek when I replaced the single pivot for some dual pivots.

One other option is to put the nut inside the head tube. I did this until I was able to get a longer recessed nut. I didn't like it this way, so I did get a longer recessed nut and ground it down ( I couldn't find one the proper length I needed). But this will only work if you use the rear brake on the front and the front on the rear. But I am assuming that is what you did, since you didn't mention that the recessed nut wouldn't fit in the rear brake bridge. So I guess you used the front on the rear and used a nut to hold them on.

The reach could be a problem and it might not be.

i just hope you have 700c wheels for your 700c reach brakes and aren't trying to apply them to 27" wheels. that can be a real pain in the aisse if your caliper slots dont reach down far enough :) but hey, i've seen v-brakes brazed onto a '75 motobecane grand touring so anything is possible.
I have never heard of 700c brakes. But if there were such a thing, you explanation wouldn't make sense. Since a 700c wheel is smaller than a 27" wheel, then the 700c brake would be too long, not too short.

Again, this will all depend on the fork. On my Trek, I didn't need a "long" reach brake for my 27" wheel. When I decided to switch to 700c wheels, I needed to get a brake with longer reach.

yeah that makes sense. its really late and i think i had it backwards. sorry. i have been told! yes i think fork blade length (i.e. how high the crown is above the top of your wheel and thus where your drilling is) has a lot to do with it as well. for example a fork built for a 27" wheel, with 700c wheels applied, will require a longer brake than a fork built for only a 700c wheel which is ~0.5" shorter? am i okay now? :) thanks for catching my drunken misthoughts

I build a lot of bikes at work.
The road bikes come with Washers that fit on behind the caliper so to take up some of the bolt space.
This is handy if you want to fit guards or a reflector bracket there.

A late 80s frame should be for 700c.
As Raleigh were using 700c then on cheap bikes so far east countries would too.

Hey guys, Thanks for the help. This is definitely beyond my limited scope so I'm off to the bike shop for a professional fix or maybe return the brakes if it's too much trouble and cost. This just seemed like a fun project to work on over the weekend and turned into a bike ruiner :) This is a great forum though, thanks for all the info.

Drilling might not be needed, it depends on the fork. I didn't need to drill my fork crown for my '85 Trek when I replaced the single pivot for some dual pivots.
Not all dual pivot brakes use recessed allen nuts. I have a pair of 105 DP long reach brakes on an '83 Trek road bike and they have long mounting bolts and external nuts at both ends.

However, the OP's new brakes certainly do have short bolts and recessed mounting nuts. As RG noted drilling out the back of the fork crown to 5/16"/8 mm is easy and it will then accept the recessed nut. Drilling the front side of the rear brake bridge is a good deal trickier.

Incidentally, my Trek came with 27" wheels and when I substituted 700C wheels, the brake pads on these 105 DP's could be adjusted low enough to match. The JUST made it but they do work.

I have never heard of 700c brakes. But if there were such a thing, you explanation wouldn't make sense. Since a 700c wheel is smaller than a 27" wheel, then the 700c brake would be too long, not too short.

Again, this will all depend on the fork. On my Trek, I didn't need a "long" reach brake for my 27" wheel. When I decided to switch to 700c wheels, I needed to get a brake with longer reach.

now that i am not quite as hazy, i think "700c brakes" was my personal euphemism for simple short reach calipers. like some people run on tight fit track frames (sigh). ran into this problem long ago with a road conversion from an early 80s bike to 700c wheels using the stock fork with a tektro dual pivot. there is another thread here (http://www.bikeforums.net/showthread.php?t=413989) about all this short/long reach brake action, and there is a difference. i just didn't know how to pick my words. thanks for the wrist slap :)

As RG noted drilling out the back of the fork crown to 5/16"/8 mm is easy and it will then accept the recessed nut. Drilling the front side of the rear brake bridge is a good deal trickier.


I've done it. I grabbed the shank of my drill bit with a vice grip. Worked it back and forth by hand for 5 or 10 minutes till it drilled out the front portion of the brake bridge.

I've done it. I grabbed the shank of my drill bit with a vice grip. Worked it back and forth by hand for 5 or 10 minutes till it drilled out the front portion of the brake bridge.

I like it :), but it's not quite as elegant as the BF member that made that reversed drill bit for this purpose (too lazy to search for the thread)

I've done it. I grabbed the shank of my drill bit with a vice grip. Worked it back and forth by hand for 5 or 10 minutes till it drilled out the front portion of the brake bridge.
That's exactly how I've done it. Great minds... and all of that. :)

A short shank drill bit makes the job a bit easier too.

Not all dual pivot brakes use recessed allen nuts. I have a pair of 105 DP long reach brakes on an '83 Trek road bike and they have long mounting bolts and external nuts at both ends.

However, the OP's new brakes certainly do have short bolts and recessed mounting nuts. As RG noted drilling out the back of the fork crown to 5/16"/8 mm is easy and it will then accept the recessed nut. Drilling the front side of the rear brake bridge is a good deal trickier.

Incidentally, my Trek came with 27" wheels and when I substituted 700C wheels, the brake pads on these 105 DP's could be adjusted low enough to match. The JUST made it but they do work.

I didn't know that. I have never seen a dual pivot brake that didn't have recessed nuts. But that makes sense, since they would have needed to be made for all the forks that haven't been made for recessed nuts yet when they first came out.

Yeah, on my Trek, When I measured the reach, it was very close, so I opted for a longer reach that I new would make it. I think I had about 1 mm of play, but depending on how well I centered the ruler in the mounting hole could mean I couldn't use the shorter reach brake.

That's exactly how I've done it. Great minds... and all of that. :)

Every time that I hear that said I wonder if feeble minds might think alike too. :) :)

Every time that I hear that said I wonder if feeble minds might think alike too. :) :)
Hey, our technique works doesn't it? We can't be that feeble minded! :p