Centerpulls are really stinking it up
 

My wife's bike, an old Nishiki International I've refurbished, has brake problems. We've got new Dia-compe aero levers going to two old dia compe centerpulls. The front centerpull is NOS, the rear is older but in fine shape. The brakes suck. They're super mushy, low power, and they barely even return after being squeezed. They don't just suck, for all intents and purpose they simply don't work.

Now before you just say centerpulls just plain suck, I have the same dia-compe centerpulls on my fixie and they work great. I like centerpulls and have used them with fine results and the ones on my wife's bike are in better shape than the ones on my fixie. The cable-routing is fine, no major excess or lack of housing, the housings are new and so are the cables. I actually have replaced the cables twice. The first install I used teflon stuff, the brakes sucked so I suspected maybe cheap teflon rubbing off and gumming up the housings so I redid everything with regular cables and housing and it's exactly the same.

My fixie has non-aero levers but I can't imagine that would make a huge difference in performance of the centerpulls. Any ideas what might be going on? I'm considering going to new sidepulls but I don't know if I could find ones with enough reach first of all, and 2nd none of this makes any sense. The brakes basically don't work and I have ridden centerpulls happily. I don't see how it could just be the brakes themselves. Am I missing something? Could the levers somehow be screwy?

Something I just thought of- I've only had experience with tektro and dia compe aero levers. The tektros accepted the cable into a straight slot and I liked that a lot. the dia compes have a rounded ferrule that loosely fits over the housing and loosely fits into a rounded depression. I worried about this when I installed the brakes, could the cable somehow be kinked at that point?

The Dia-Compe levers you're using aren't 287-V's, are they? Probably not, but just in case they are, those are designed for linear pull brakes (v-brakes), they won't work well with other types of brakes. Also, regarding the return springs, do you know if the brakes spring back well without the cables attached? If so, it must be something with the cables; if not, it's the return springs on the brakes that are causing that problem. I give mine a couple of shots of pure silicon lube at the pivots every few months, too, to keep the action smooth.

Like you, I've had excellent luck with centerpulls. My current everyday road bike has them, they're 1983 "Schwinn Approved" Dia Compes with Kool Stop salmon cartridge pads for v-brakes and Shimano Exage aero levers. I honestly couldn't ask for better braking performance, and the reach is pretty much unmatched-

No, they're just regular levers.

The brakes are fine. The front is NOS and has a super strong spring. I suppose it has to be a problem with the cabling, that's why I'm wondering about that interface with the rounded ferrule. I really hate that thing because it's completely loose and when setting everything I'm never sure that it's seated in there correctly.

I have a set of Dia-compe aero levers and have never liked them. Although I did not have the problem you have, the first set that arrived had no hole in the ferrule for one of the levers. And the rubber hods never fit snugly so they look bad. I suggest using a pair of Shimano Tiagra brake levers, available on-line. These are excellent quality at a good price and should give you no trouble.

Are the tektro's unusual in having a slot for the housing to sit in? They're pretty wide (the campy ergo knockoff type) so I'm guessing most aero levers use the rounded ferrule?

Right. I think you figured it out already, but if you insist on center pulls, then use the best cables you can get with the thickest guage cables. Cheap cables are mushy to begin with. Add that to center pull brakes which are buggers anyway and you have a troublesome combination.

I think these statements are correct:

Mushy feeling is due to cable stretch, housing installation or soft brake pads
Braking power is affected by the mechanical advantage of the lever/brake combination
Springiness is due to the spring in the brake and the spring in the lever.

Since the cables are new, they're probably not stretching and are fine, like you said. I've only used shimano brake levers, and the housing sits against a flat part inside the levers. I've been told NOT to use a ferrule on the lever end, but i've always ground both ends flat so they make firm contact. Housing travel at the handlebars or at the lever end can result in mushy brakes. Sheldon Brown recommends taping the housing to the handlebars with the brakes engaged so the tension forces the lever-end of the housing against the stop inside the lever.

http://www.sheldonbrown.com/cables.html

The levers you got may be fine, since you pointed out that they are not the V-brake compatible levers. Another way to change the mechanical advantage is to adjust the length of the transverse cable. I don't know much about this, but Sheldon's covers it here:

http://www.sheldonbrown.com/cantilever-geometry.html
http://www.sheldonbrown.com/canti-trad.html

It's about cantilever brakes - i don't know if you have caliper centerpulls or cantiever centerpulls but I think the stuff about the transverse cable applies to both.

You said the brakes are plenty springy, but I guess you could take a look at the spring in the lever, but you probably can't adjust it. Could be the cable installation is affecting the springiness also.

Let us know what works!