Setting up Vintage Canti's: Dia Compe 962 cantilever brakes

I noticed the other day that the brakes on the Cresta GT were a bit mushy, not as tight as I would have liked.  I spent some time adjusting them, a cable adjustment here a pad tweak here and...not much improvement.  Frustrating.   I found a Park Tool video on adjusting canti's with smooth brake pad posts and although not exactly a vintage guide it gave me a frame work from which to work through more systematically.

Vintage Canti's present a few challenges; 1) the canti post on most vintage bikes has only one hole for the spring vs. the 3 on more modern bikes so there is no option for adjusting the spring tension at the post, 2) the brakes don't have an adjustment screw like the one pictured above on the 1990 Ibex that allows for centering the brake arms. and 3) the pad toe in/out , up/down adjustment  is all the same bolt so its easy to screw up your work with one wrong twist of the wrench.

You also need three, yes three wrenches to do the various adjustments on the brakes and cables; 1) a 8 mm for the pinch bolt for the straddle wire cable, 2) a 9 mm for the bolt that allows you to move the straddle wire carrier up and down on the brake cable and finally 3) a 10 mm for the brake pad bolt mentioned above.  Really guys?

I am no expert and I strongly recommend watching the video I linked to above but here is step one.  You don't want the straddle wire carrier - the triangular piece above- to be too high or low, they recommend not lower than the bolt hole in the fork so I started above that up front.  Mr 9 mm wrench snugged it up once it was in place.

For step two they recommended the brake arms line up so the bolt that the pads go through is roughly above the Canti stud.  If its either too splayed out or two leaned in it weakens the mechanical advantage of the canti arms.  What I had above wasn't perfect but it was on track, in this case having a 4th hand tool like the Park BT -2 would have come in handy, I am cheap so I will probably get the Pedro's version on amazon that is about half the price.  In theory it grabs the cable next to the pinch bolt and with the bolt loosened and allows you to pull the cable in or out to adjust to the desired length with just one hand, leaving the other free to tighten the pinch bolt when things are aligned just right.  Doing that without the tool is a contortionists exercise in frustration but by marking the straddle cable and noting the line up of the brakes to the canti studs I got close moving the cable incrementally.  Planning to order a Pedro's cable puller though.

And finally in step three you adjust the pads, and here was the revelation for me, now that you have the cables set  you move the pads to the rim, you will notice in the shot above this one I didn't even have the drive side pad in the brake arm, you don't worry about the pad set up until this last step and then you make your adjustments moving the pads in or out as necessary.  You may also find that to get the pads centered on the rim that they end up asymmetrical, i.e. your showing more brake pad post on one side than the other, that is ok.

After time and fiddling and deep breaths, and ok some adult language,  I got to the point where the lever pull was where I wanted it and the tire still spun freely.

And then I repeated the process for the rear brake and it eventually ended up where I liked it.  Not an expert yet but having a framework to follow certainly helped.

EDIT:  there is a fourth step that I forgot and it resulted in this

I thought I had tightened all the brake posts after adjusting them but I was obviously wrong about that so here is step four.

These vintage Dia Compe canti's have a hex nut one one side so you can loosen it to make the pad adjustments and a hex head on the other side which allows for..

..using an allen wrench on one side and a box end wrench on the other to get the brake post very SNUG so it doesn't rotate like it did for me.  Do the both end snug trick on all four pads to be extra sure the post is secured in place.

So why, you might ask, don't you quit whining and use some modern canti's like the Tektro CR 720s that have the adjustments you were just lamenting not having?  Well the challenge of a mid 80s Steel touring bike is that the distance between the front canti studs is about 75 to 80 mm which is too narrow  for modern canti brakes to handle, they can't close on the rim and allow the pads to seat properly.  I discovered this with the 1986 Schwinn Passage when I had the idea to use the CR 720s during its rebuild.  On the back they are fine, on the front not so much and that is where most of the braking power comes from.  If I ever do find available modern Canti's that will work I will write about it.

Ride. Stopping is good. Smile. Repeat.