Classtime 

OP should have asked in C&V.

smd4

While there is obvious overlap, this is clearly a mechanical question best solved here.

Trakhak

Continuing the dual-pivot/single-pivot digression:

Aside from the comparative ease of centering the brake, there's nothing inherently superior about the dual-pivot design. If there were, then the much earlier Altenburger Synchron (below) would have started a trend.

The main difference in Shimano's dual-pivot design is that they (rather sneakily) changed the geometry of the lever and caliper to reduce the hand effort required for a given level of braking power. Sneakily, because there's a trade-off---the brake pads must be adjusted very close to the rim's braking surface, or else the lever would be close to bottoming out for panic stops.

Clever. I guess some Shimano engineer realized that spoke and rim technology (and most road surfaces) had improved greatly in the previous decades, reducing the incidence of rim deformation resulting from, e.g., spoke breakage, and that brakes' mechanical advantage could be altered to take advantage of those improvements.

smd4

I use brake levers from the mid 1980s. Long before Shimano introduced dual pivots. There is absolutely no way I could have ever adjusted my Dura Ace 7400 sidepull brakes to be nearly as strong as my 7700 dual pivots with 7402 Aero levers. Simply isn't possible.

One of the reasons those Synchrons don't work well is the thinness of the brake arms.

Classtime 

Too many solutions “here” are replace with dual pivots. C&V solutions are KoolStops, adjust, and those brakes will work as well as they do on my Medici.

smd4

BS. It's a mechanical issue, not a C&V issue. He says it's an early '90s bike, so dual pivots would be perfectly acceptable.

Classtime 

OP says “How do I fix this?”

smd4

Right. Which is why it's here in the "Bicycle Mechanics" forum. And he's been told how to fix the problem several times. I did so in post 44. The suggestion to switch to dual pivots is just to make the braking better--it's not meant to fix the original problem.

Dave Mayer

A dual-pivot brake for the front should cost less than $20 to your door via. Aliexpress. As I posted earlier, any dual-pivot brake will be superior to any single pivot brake (ever made) as it features greater mechanical advantage and it self-centers. Plus it will come with new pads, to replace the 30+ year-old hard hardened rubber on your current brakes.

I have a large heavy bin of vintage brake calipers which include the highest-end offerings of Campagnolo, Suntour and Shimano. The best of all of them were the Dura-Ace 7402s, of which I have a few sets. These are still inferior to any no-name dual pivot brake I can buy online for the price of a burrito and a beer.

Next, replace all of your too-short cables and housings; this should be done yearly anyway, plus the new stuff is much smoother and less spongy than the old unlined stuff.

Finally, discard your bars, as you indicate that someone drilled them for aero routing. Whoever did this was dangerously irresponsible; these bars are not meant for this; the stress risers will eventually cause a bar failure. I know from real-life experience after using some-second-hand Cinelli bars that someone had drilled for (pointless) aero routing. About as close to dying as I've ever come.

RoadWearier

So because of two 3 mm holes, your handlebars, what, snapped in half? If you say it happened, I believe you. But honestly that's hard to fathom. Also hard to believe that every cyclist changes his cables yearly. I've talked to a lot of cyclists and none have mentioned doing this. And as a quick update. I recentered the calipers already. They work fine now. No cable changes required. Thanks for all of the advice!

Trakhak

From this page:

Dual-Pivot Sidepull

The dual-pivot brake achieves both greater leverage and the ability to work with smaller pad-to-rim clearance by its improved centering, by using two pivot points to define a line of action about which its two arms are constrained to move equally, meaning they remain centered. This feature is essential in reducing the pad-to-rim clearance needed for a higher mechanical advantages of about 5.6:1.

Greater leverage also required compromise. The offset arm (the short one) sweeps its pad upward into the tire so that its pad position must be adjusted as it wears. Also, the brake cannot track a crooked wheel with, for instance, a broken spoke, and because it has a high ratio, it works poorly, if at all, when the quick release is accidentally left open. And finally, it runs out of hand lever travel 40% faster with pad wear than the former single pivot brake. Low pad clearance and narrow flange spacing of current rear wheels make this brake drag when climbing hills standing. In response, racers often climb with the rear quick release open... and on occasion, fail to close it after reaching the summit.

Part of the light feel of the dual-pivot brake arises from the lower (reverse) ratio of the caliper, whose springs do not exert as strong a return force on the cable. With this lower force, a return spring has been added to the hand lever to give the desired return force but with lower cable tension during free motion of the brake (before making contact with the rim). This makes the brake FEEL even more forceful than it is because it has such a light free motion.

smd4

I hope Jobst recalled that "Light Action" levers (with return springs) came out long before (modern) dual pivots. This certainly doesn't make the brake "feel more forceful." (whatever that means).

RoadWearier

How do you know these handlebars didn't come pre-drilled? Is there some way to tell?

smd4

I wouldn't even take the risk...Just buy a new pair of Cinellis and carry on.

RoadWearier

So if I understand correctly.....In order to not make this bike a deathtrap I need to buy a handlebar, handlebar tape, new brake cable,new housing, new dual pivot brakes, new stem? Lol. By the time I do that I could buy a new to me aluminum road bike and come out ahead if I sell the bike.

I appreciate all of this advice but I am going to follow none of it. Like I said before between recentering (Seems like the rear bolt would loosen, and the front bolt seemed to move the whole shebang left or right depending on whether I turned it clockwise or counter clockwise...is that right?). And lubricating the pivot and spring and actually riding the dang thing (50 miles over the past few days, Yay!) the calipers seem to move much more uniformly. They stop ok but I'd be the first admit by trek fx3 stopped much better. Maybe I will get some Kool stops for Christmas? Other suggestions on pads? Will it make a difference? Maybe I'll look into dual pivot on the front.

Kontact 

No. The calipers are fine. The bar may be fine to fit you, but you said you wanted to sit higher and that implies a stem. You can't get the stem off without unwrapping the left bar and removing the too-short housing and lever. You might be able to reuse the tape.

Stem and housing.

FBinNY 

+3/4

Only housing and tape for now.

There's nothing seriously wrong with the bike, nor any reason to spend more than pocket change solve the minor mechanical issues.

So it really boils down to fit, and your preferences. Looking at the photo of you straddling the bike, I suspect that the frame may be too large (unless you wear pants very low). Combined with the desire to raise bars yet, may not be suited to your needs. Plus taller stems of comparable (handlebar) fit and quality are rare, if they exist at all.

So before spending anything more than the cost of a cable and tape, I'd step back and consider whether this is really what you want or need.

OTOH the few dollars spent on the cable and tape, would allow you to ride this while you consider ALL the options.

conspiratemus1

Just out of my curiosity, would you mind posting a photo of the front brake and handlebars, taken from the front just like the very first photo you sent?
I promise not to comment on anything, other than to thank you.

Dave Mayer

Brake cable housing is 5mm in diameter, so the hole is necessarily bigger than that. Then the cable has to exit the hole in the bars at an angle, so it has to be drilled in an oval shape, at least 10mm wide.

My Cinelli bars had had been drilled on the undersides. I've ridden thousands and thousands of miles over decades on Cinelli bars, and they are bombproof. But with this particular set of bars I was attempting to accelerate through an intersection with traffic coming in hot from both sides, I was pulling up on the bars and the right side snapped clean through at the hole. Only thing holding it to the bike was the cables, electrical tape and the bar wrap. There is no way that an alu bar should be drilled like that, factory or otherwise.

New cables and housing cost like what: $10. A better front brake: $20. Bar wrap: $5 direct from Asia. Most people will spend more than that on a restaurant meal, and their lives don't depend on it.

Kontact 

One would think that everyone riding a road bike before 1992 didn't have brakes that worked.

smd4

They worked. Just not very well. And not nearly as good as dual pivots.

One would think you would know this.

shelbyfv

smd4

I know, right? Dude's got a pretty nice bike, but won't do anything to make it rideable, safe, or even better.

The cheapness of folks on this Forum knows no bounds.

Gresp15C

Whether it's worth trying to fix something that could be replaced with "better" is a philosophical question.

But old sidepulls can be restored to operation if they were decent quality to begin with, and not allowed to deteriorate beyond repair. Even Dia-Compe. Most of the time, it just takes "disassemble, clean, reassemble, lubricating along the way." Lube the spring contact points on the arms.

One of the reasons new brakes work so much better is that they always have new pads, and typically some attention is paid to the cabling when installing them.

smd4

What a silly thing to say. "Old" brakes were new at one time, too.

My brand-new Dura Ace 7400 single-pivot side pulls had (obviously) brand new pads, very close attention paid to the cabling, and the mechanic who installed them had a ton of experience and was fastidious and nearly anal about brake adjustment for optimum performance (me).

They absolutely pale in comparison to the 7700 dual-pivots. There is simply no contest.