adkguy

I just bought a 1986 Fuji Palisade and its in great shape. It comes with Dia Compe 500 brakes. The front brake is well adjusted but the back break is really loose. I can pull the brake lever in all the way and it barely touched the rim of the wheel. I'm new to bike mechanics so I have no idea on how to adjust the brakes to make them tighter. Any suggestions? I'm at work right now so I can post pics of the brakes when I get home. Thanks!

Ratzinger

Unless something is majorly wrong or broken, you probably just have to tighten the brake cable. Loosen the nut that clamps the cable in place, with the other hand hold the brakes closed, and pull the cable tighter. Then tighter the nut.

dsbrantjr

Park Tool Co. » ParkTool Blog

fietsbob

BuyNew Brake pads, and then do the adjustments , My Guess is they are Worn, and thats part of why there is so much lever travel

and if there are a quick release in them Adjust the Brakes with the QR Closed.

this is a QR version https://velobase.com/CompImages/Brake...1DC189FEB.jpeg

this is Without a QR .. https://velobase.com/CompImages/Brake...C632E719E.jpeg

Dave Mayer

Or just chuck the brakes and get something better. A pal of mine crashed his bike into the back of a car, totaling most of the bike. But he salvaged the Dia-Compe sidepulls, and I installed them on my Gitane.

Very poor braking performance no matter what I tried. New pads (several), new cable housing, and new brake levers. Nothing fixed the scary braking. It became clear why he crashed his bike.

A $30 pair of dual-pivot brakes will be a world of improvement.

Phil_gretz

May I ask which brake levers you were using with the DiaCompe calipers? And the pads were KoolStop salmon or equivalent?

Dave Mayer

Original brake pads (hard and useless) were quickly replaced with Kool Stop grey, then Kool Stop red and then Scott Superbrake pads. The Scotts are better than anything. I assume they are more or less the formulation of Kool Stop salmon. The brake levers were upgraded to Campagnolo Ergopower brake/shift levers.

Bottom line: the old Dia-Compe calipers are hopeless. Poor mechanical advantage, flexy weak arms, cheap fittings. Whenever I find these on a bike I'm about to overhaul, they go straight to the trash. Buried deep, so no one is tempted to reuse them.

The best single pivot brakes ever are the Dura-Ace 7402s. Even these are inferior to any dual pivot road brake, no matter how cheap.

fietsbob

Kool Stop ('salmon' compound) Pads were supplied to the Scott company for their "superbrake"..

TireLever-07

Make sure your brake quick release is in the closed position too. It lets you remove the wheels with the tire fully inflated. I'd keep trying to adjust the main anchor bolt on the brake bridge. Modern dual pivot side pulls are better brakes. Good luck.

williexwill

Anyone know the acorn nut size for these brakes? Mine unthreaded and popped off and I need to find a replacement. If I can get the nut without having to dismantle the whole mechanism or ride it to my LBS, that would be ideal. Likely M6?

JohnDThompson 

Almost all threaded brake pad shafts are M6.

ShannonM

Just about the only thing I agree with in this is the greatness of the 7402 brakes. They're awesome, no doubt. But Dia-Compe made the "hidden spring" Superbe Pro calipers for Suntour, which are, in my opinion, even better, especially when paired with Shimano SLR levers. (The Superbe Pro levers are too small for my hands, and SLR levers are the 2nd-best brake lever ever made.) I've got GCN-400s on my Fuji, with TRP RRL-SL levers. They're perfectly serviceable, although not the smoothest pivoting I've ridden. I had Dia-Compe centerpulls on a 27" to 700C converted Schwinn Super Le Tour, which I rode fixed for a while, including off-road, and I never needed more brake than I had. They were a bit tricky to set up without squeal, but once they were dialed in, they were good brakes. Paired them with Dia-Compe SS-5 MTB levers on North Road bars, worked well.

I'll also say that, although it's a minority position, I prefer single-pivot calipers to dual-pivots, at least with short-reach brakes. Dual-pivots' hand effort is just too light. I like a bit of resistance in my brake actuation. This has been true for me with bicycles, motorcycles, and even cars... I don't like super-light brakes. The 650B conversion on the Fuji will use Tektro R559 dual-pivots, and I'm hoping that the longer arms and increased flex will increase the lever effort enough for me to like them.

RGC 500s are great brakes.

--Shannon

Dave Mayer

Dia Compe: I volunteer as a mechanic and instructor at a high-volume bike Co-op. I've worked on hundreds of bikes with Dia Compe (shudder) brakes. I've thrown dozens of these sets of brakes away, making deliberate provisions that they head straight into the landfill without any other user intercepting them and wasting their time or jeopardizing their safety.

Including last week, on a customer's bike in which it was impossible to keep the rear caliper centered no matter the number of fine tweaks of the nuts holding the caliper and the arms in place. My instruction to him was to come back in a today so we can strip his brakes off of his bike to be replaced for something actually good, like a $30 set of Tektro or clone dual pivots. Good riddance.

Overly strong springs and flexy caliper arms, a hallmark of Dia Compe calipers, is not a good thing in terms of braking performance. It requires unnecessarily high hand force to overcome the springs, and the flexy arms lead to a spongy feel and reduced braking power.

ShannonM

We're just going to have to agree to disagree on this.

Yeah, I've seen some Dia Compe brakes that I wouldn't melt down for fishing weights. I've also had Dia Compe brakes that rank up there with the best I've ever used. Sidepull, centerpull, and cantilever. It's true that the sidepulls have been uniformly higher-effort than Shimanos, but not by a lot, and there's more to good bicycle braking than lever effort anyway. As I said, I prefer some squeeze in my brakes. (I have XXL hands and sausage fingers, which may explain this.)

I've had dual-pivot brakes on one bike, 105SCs, and I didn't really like them. Felt great on a test ride, but over time, they were just too light in the hand. I rode that bike for years, and never felt the need to change the brakes, so I didn't hate them... but when my next bike had single-pivots, (the Dia-Compe-made Superbe Pros, to be specific,) I immediately loved them. They're among my favorite road brakes ever, right up there with the Shimano 105 / 600 tricolor / Dura-Ace SLR single-pivots and the Campagnolo Chorus Monoplanars. (Which might be my favorite short-reach brake ever, so long as you don't use 80s Campy levers with them.)

I've always had a sneaking suspicion that Shimano came out with the dual-pivot calipers because their STI brake / shift levers were so blade-heavy because all of the shifting guts moved with the brake lever. So they needed to get back in the caliper what they'd given up in the lever, and so when they were paired with a regular brake lever, the whole system ended up really light in the levers. (I have no evidence for this, it's just a hunch.)

I've never been a fan of Dia Compe aero road levers... I don't like the shape, they're a bit draggy, and Shimano SLR levers changed the game forever anyway. Nowadays, the TRP RRL-SRs are all I want under my hands, but if they didn't exist, I'd put SLRs on everything. 105, 600 / Ultegra, Dura-Ace... even R100 or Tiagra... doesn't matter. Pick 'em by looks, they're all fantastic.

Brake Levers Matter

--Shannon

theofam

@ShannonM, based on the above posts, I need advice.

My latest effort is getting a 1980 Schwinn Voyageur back from a rusty grave. Today, while disassembling the front Dia Compe 500 brake for cleaning, the 8mm nut for the QR sheared with the bolt (see below pic).

Based on your input, I shouldn’t care, because they’re not good brakes to begin with. So, I’m now open to alternatives. That said, I’m not looking to invest much in this free-to-me bike to get it back on the road, so I’d prefer to reuse the Dia Compe levers stamped 235.


This is where my noob status kicks in hard. Do I have to use Dia Compe brakes with Dia Compe levers? Can I mix and match manufacturers? I can’t imagine the lever type would preclude me from using a dual-pivot brake. Or, would it? As you can tell, I don’t know what I don’t know. But, I’m eager to learn!

blamester

If there is an lbs close you can probably get that part of them.
New cables, new pads and properly setup to suit you and those brakes are fine.
If you ride very fast and brake hard a lot there are better brakes. And these are not designed for that.
You just got to be realistic. It was a cheap bike not designed to be raced or pushed hard.
​​​​​​But it will brake consistently if you set them up properly. Proper setup means you can reach and pull them easily and consistently.
So set them up good now see how you get on.
And then you have a base.
You could then try a new caliper or lever and you would know for sure whether it is better or not.
Some will tell you to get dual pivots and it will better.
But they don't know the size and strenght of your hands or your weight or the speed you ride.

dedhed

Actually the Voyager was an upper level touring bike in the Schwinn lineup with a list price of $350-400. Not a Paramount but not a Varsity either.
They are, while not a Trek 5-720, somewhat popular, especially the chrome ones.

Personally if it was mine I'd get measure the reach and put on a set of Tektro nutted mount dual pivots. Try them with your levers if you like them and see if there is any issue. If not satisfied put on some cane creek levers.

blamester

The brakes are not top of the line.
But they may well be good enough.
Test this one first. Then replace something if you have to. Simplest easiest way.
Unless you think dia - compe made brakes so bad they are actually dangerous to ride even briefly.

Mr. 66

That quick release mount is not great engineering, the other thing the manufacturer did was peen the nut so they didn't rattle loose. That said it shouldn't have broke, usually they get the threads stripped. I learned the hard way they shouldn't be taken apart.

theofam

Peened the nut - that explains why the rear brake was difficult to disassemble, too. Each nut, front and rear, on the brakes was rusty to the point I couldn't discern it had been peened. I should have cleaned the QR assembly in place.

theofam

dedhed - thanks for sticking up for my Voyageur! The research I've done coincides with what you wrote in terms of it being a higher-end offering of Schwinn.

blamester thanks for weighing in. I'm unaware of an LBS in the area that stocks vintage parts, but eBay has DC 500 brakes I can pick up inexpensively.

Miele Man

I have a pair of Dia-Compe 500 brake calipers paired with a pair of Dia-Compe AERO brake levers (don't know which model) and I absolutely love them. Good positive braking when I want it but a nice light feel to the brake levers when braking. I Don't have to be Hercules to stop with this brake setup.

Cheers

Dave Mayer

Alternative brake suggestion: try some Shimano RX100 or Shimano 600 (6403) dual pivot brakes, and matching aero levers. If you like Dia-Compe brakes (shudder), then these cost-effective brakes will rock your world. The RX100 calipers come in a longer-reach version.

I have a 50 pound bin of (good) brake calipers; I've ridden on everything going back 50 years, and these two rim brakes are as good as anything.

I've yet to try the 9100 Dura-Ace direct-mount brakes, but these will set you back $300 for the set, plus you need the compatible frame.

theofam

Thanks for the suggestions. I’ll begin the search. As for the Dia-Compe, I don’t have an opinion of them, as the bike they’re from was too far gone for me to ride it when it was given to me. That, coupled with me being a complete noob, and I wouldn’t know good brakes from bad yet.