I made a booster brace out of a spare arch from another centerpull for these brakes too. It's hard to see them in the photos I posted above because the bag was in the way, but when I was experimenting with the brakes on another bike to see if I liked them I took a few photos.

Pre-polishing photos so the brakes don't look like much at this point, but you can at least see the brace:




The brace made a whole lot of difference in how much the back arch flexed and twists as the pads set down on the rim. It made the difference of the lever hitting the bars solidly with medium-high effort to then almost taking two hands to get the lever to barely tap the bar tape. The pads visibly squish a LOT at that point. I also have a very strong modern fat alloy cable stop at the top of the headset (10mm stack height!) -not the flexy thin steel ones from vintage bikes. So there is very little flex anywhere but in the brake arms themselves. The arch can't flex outwards when the arms press inwards.

I didn't bother putting a booster arch in the back. The rear brakes don't need that kind of power. The fronts have awesome stopping power, as much as this bike had when I was using Ultegra dual-pivot calipers. The return springs on the Dia Comp are much stiffer than those on the modern DP caliper though so it takes a bit more hand strength to get the same amount of braking power because of overpowering the spring. I figure in the old days they needed much more return spring due to the inferior cable housings back then. Modern brakes can be built assuming that lined cable housings don't hang up as much so the brakes don't need as much spring-back to pull themselves back open and slide the cable back thorough the housing.

Perhaps due to the higher lever pull there is slightly more feel at maximum braking? When the lever is let off the brake backs off quicker?

It's hard to tell. These brakes are pretty awesome, and because of the booster I don't need excessive toe-in to keep them from squawking and making noise under hard braking. The only time they make a peep is if I am braking really hard for that last 12" before the stop they make the slightest of herp of a noise as they come to a stop. They work very well in the wet too as I was able to get some good testing riding in a rainstorm last week for 50 miles. The salmon KoolStops made a mess of the rims and the gumwall tires in the rain, but they do that...

Eye nice, [MENTION=202466]Amesja[/MENTION]!

Nice engineering, Amesja. If I needed to drastically augment my vintage centerpull brakes, I would follow your example.

I didn't originate the idea, someone else here thought of it first. I saw it in a post a while back.

It's an easy mod. Just file/grind off all the parts on the back portion of a Dia Compe brake arch that stick up until it is flat, then smooth it off with progressively finer sandpaper until you have hidden all of your file marks.

Then for funsies I put in an M7/M5 thread reducer after tapping out the center hole to M7. I fixed it in there with a dab of red locktite so it would stay. Now I can hang the fender and the mini-rack from that without worry about messing up the aluminum threads it if gets removed/replaced a few times and I can use a common M5 bolt.

I used the broken-off bracket from a water bottle cage as my first booster plate, for a Weinmann caliper on my UO8.

As thin as the flimsy bracket was, I still had to use longer bolts iir, and it worked perfectly after I adjusted the hole centers with a round file. This after carving some extra tire clearance into it.

Since the booster plate doesn't have to sustain any bending load at all, it can be effective even if very thin and carved away.

I made this one out of 3/32" aluminum, and even as tall as it is the rear braking is night and day better than before I put it on. It's for cantilevers, but you get the idea:



I sawed the big eccentric adjuster hoops off of the lower ends of this aftermarket brace, making it shorter but still clearing the 700x40 hybrid tire. It's secured by a washer sandwich.
It's also quite effective. Get a load of how much metal is supporting both ends of the canti studs!:

A couple more pics of the front:

Ooh! Ah!

I forgot to mention about how well the Tektro Alloy Brake Cable Triangle work with the Dia Compe brake double-ended straddle wire.

They come in both black and silver. You can slide the straddle wire in from the top after removing the pinch bolt first. It comes with little tiny fixing screws that keep the straddle wire from sliding either way but I didn't use them, opting instead to let it "float" rather than be fixed in place. I had originally wanted to use the VO Grand Cru pulley-style straddle wire hanger but they are not making/importing them at the moment so I opted for the Tektro instead. Those cheesy stamped old-school wire hangers never impressed me and always made center-pulls look cheap and cruddy. They look so flimsy, and aren't wide enough IMHO to get a good lever pull ratio.

I liked the look of the Paul Moon Unit straddle cable carriers but they were a bit too pricey for my blood (as are all things Paul.) The Tektro's were <$7 each with shipping from Amazon and look/work great.

Bippity-bump!

Those cantilever hangers really help a ton to quicken the action. Here's a shot of mine on my Steamroller in conjunction with Shimano SM-CB90 cable releases. I'm using them F+R with Kool Stop MTB pads and they're working perfectly. Can anyone here advise me if cutting back the the straddle cable retainer on the arm slightly so I can pop the cable out easily to fully release the brake is a bad idea? Tons more pics on my blog.

MAFAC on MAFAC love:


Gotcher Comp's right here:


Dime 'o dozen centerpulls:


The rare, shiny, and mediocre Dura Ace centerpull:


Racers look cooler with a front rack:


and finally, properly posted:

More Mafac. These are 2000s with brazed on pivots with a TA bag support and a custom made Mariposa light bracket.

center pull brakes is hard to adjust?

Not really.

I had before one old road bike 1970 i fix for one man. Brakes is was centerpull is has rust too hard to adjust i put in that bike finally side pull brakes

Depends on what centerpull and what sidepull you're comparing to. Most MAFAC centerpulls have more degrees of freedom-a curse and a blessing. For example, most of them you can adjust the pads not only up and down, but also the angle that the pad hits the rim. The straddle cable is adjustable on RAID's and Racers, for example, as well as the yoke cable. But that just gives you another knob to tune, which is sometimes useful.

I have two bikes that couldn't use sidepulls. All of the side pulls I tried on my Lotus Classique limitied tire size, as they "drooped" (for lack of a better term) down below the fork crown. I found that all of the material on MAFAC Competitions was at or higher than the bottom edge of the fork crown, allowing 33.3 tires with a few milllimeters to spare. On my VO Randonneur fitted with 650b wheels, Tektro 559's were a few millimeters short of reachiing the rim. MAFAC RAIDs, however, did the job. Both took more time to setup than, say, Tektro's fine sidepull offerings, but it was well worth it.

Not really more difficult, they're fairly straightforward, but take a bit more time.

A couple more shots.

figured this belonged here...
allen dome bolts change the looks of MAFACS, i love it !

fyi... braze-on mounted racers with original pads, they do stop me on a dime and could lock the wheel easily...
this is the brass bushing edition !

Just waiting for the right bike:

These pull from the centre:





Weinmann Delta's

I've seen a little bit of discussion about these brakes. They are supposedly very nice brakes?

I want your hoods

Looks like the cockpit of an old aircraft

No Delta's?