scarlson 

I bought a set of Gran Compe NGC450b brakes a couple years back for $30, thinking they were pretty cool looking and for the price, and gee wiz ball bearing pivots, I could not go wrong. (below picture not mine)


I did not know what I was getting myself into. I quickly realized they were really short-reach - short enough that the only bike of mine they'd work on was my Vitus 979. So I put them on there. Yes, these brakes are shiny, and yeah, the braking power is good, but the noise they make, my god!! Others on the Cycling UK forums mentioned this too. Also, everything down to the pads and straddle cable is proprietary, and I only had enough hardware to set up one brake. Naturally, I took them apart. The bearings inside are tiny! It is no wonder they squeal. They can be forced out of alignment with minimal pressure.




They sit on a little stepped post, 6mm on the outside and m5x8 threaded on the inside. Each bearing is 4mm thick, but they ride in a 7mm deep hole in the brake arm. So I thought to myself, why not add a second bearing in each brake arm? That should stabilize things! The bearings are readily available, part number MR126-ZZ. I bought ten of them for $9.


The only thing I had to make was a set of new bolts. These were somewhat difficult to machine. It starts out simple, with an M5x0.8 thread, but then there has to be a 6mm shoulder for the bearing, the bolt head has to be relieved so that it doesn't foul the outer race or seal, and everything has to be pretty concentric and fit tightly. I was able to do it on the good old Hardinge HLV-H lathe at work, before things got locked up for the virus thing.



I also machined a m6x1.0 stud on the other end, for eventual mounting of a rack. More on that rack thing later.

Finally, of course, the proprietary pads can be changed out for normal ones if pad mounting hardware is swapped for stuff from a Mafac or CLB racer.



With these modifications (after about 10 hours of work), the brakes work really well, and are quiet!

I also made a straddle cable. I soldered a little brass donut that I filed out of an old spoke nipple onto a short length of road brake cable, including the pear-shaped cable end. This way, like the original, there is a little handle to grab to quickly un-slot the cable from the brake arms on one side. I used Harris Stay-Brite 8, which is 6% silver, so I can solder with a soldering iron. The cable was 100mm long, so I couldn't use a MAFAC Competition straddle cable, which is 113mm.



Phew. Much ado about nothing, and throwing good money after bad. But coming up next, a silly little placeholder rack.

gugie 

Nice work!

Feldman

Good work, there. I made Mafac Competition straddle wires for myself the same way.

rhm

Dude, you crazy.

If I had bought a Trek 720 touring bike in 1982, it would have come with those. But alas I was a poor college student at that time and I could only afford the frame. I put Suntour Superbe brakes on it, which were fine, but I always wanted a pair of GC450''s since that's what the bike was supposed to have.

Before I found a pair of GC450's found a pair of Dia-compe 515's which are similar but different. Pretty nice, actually! Naturally, after I stopped looking for them, i found GC450's fur a good price and was happy. Until I ran into the problems you describe. I went back to the 515's, which are still on that bike.

scarlson 

I know, I can't believe I'm wasting my life like this . My only excuse is that this spoke nipple solder to cables project is a test-run for your Resilions. Stay-Brite 8 is used as a bronze-braze substitute for low-temp or less-accessible HVAC work, and I used to use it for water bottle and dynamo mounts years ago before I got a MAPP torch. I figure it's stronger than the cast lead cable ends of yore, at least.

I saw your old thread about that bike! Looks like you had some good times with it.

The NGC450b seems to be yet another instance of Trek spec'ing the weirdest and least-suitable components as OE for touring. Like helicomatic, I suppose.
I operate these NGC450b brakes with Superbe levers, which I love. Together they really do the Mafac slogan justice: un doigt suffit (one finger is enough). The bearing mod should be doable without a lathe - you'd start with an ordinary M5 bolt, then build up the threads up to 6mm with J-B Weld or the aforementioned solder, and add a washer. Or better yet, file off all but the last 3mm of the threads on one side of a set of Nitto or VO canti rack mounting bolts and fill in those remaining 3mm of threads, and use a die to thread that filed-down post to M5, then there you have it. I bet the results would be good 'nuff. I have slackened my standards due to the pandemic closing everything down, however.

bikemig 

I have a set of these and yeah I've been wondering what to do with them given the weird brake pads and straddle cable. The brake pad issue is easier to deal with than the straddle cable.

abellanti

I have also encountered these problems. I had to order a straddle cable from Germany and bought angled spacers for the brakes post. The only rims I can use that don’t squeal with using the original pads are non anodized aluminum rims. Finally the brakes work really well.

TenGrainBread 

Interesting observations. Just goes to show that "add bearings to it" isn't always the best design move.

Paul brakes (and brake levers) use bearings instead of bushings and work fine. Implementation is everything.

scarlson 

But "add more bearings to it!" seems to help
The bearings are just hopelessly small. Back in 1998 I took apart a Microsoft mouse, and found ball bearings bigger than the ones in these brakes, used to support the rollers that track the movement of the ball! (photo credit to myoldcomputers)


Some of the NGC450 brakes apparently came with bushings, called simply the NGC450 (without the suffix 'b' which must stand for ball or bearing or bad), but it's unclear which is which because the marking "NGC450" is on the center mount plate, which I think is the same for all models.

Which ones? Admittedly I had been under this impression too, but then when I took apart my Paul Racers to install the Spence Wolf-style booster plates I'd machined for them, they had bushings. And on the Paul touring cantilever webpage, they specifically mention "Rubber seals and a stainless steel bushing".

I agree, implementation is everything. My old SAAB taught me this: the pinion bearings in the transmission have a bad reputation for failure, but they're the same size and general orientation as found in other cars. They fail because they're too closely spaced and the mounting is too flexible. The subtlety of it is crazy.

scarlson 

I thought I remembered a German selling the straddle cables a couple years back. Couldn't find the listing again, though, so here I had to make one.

TenGrainBread 

Looking at the Paul site, I think you're right that none of the rim brakes use bearings. Their Klamper disc brake uses them, but I believe that is standard for disc brakes. Their brake lever (Love Lever) uses bearings in the pivot. Coupled with the strong springs on their brakes, I believe this is what gives Paul brakes their unique "snappy" feel - very smooth lever action with a strong return.

scarlson 

Yeah, gotta love those Pauls. They really do feel inexplicably great. Even though they're a little bit smushy, it comes across as modulation and not slop, because there's always more braking power to be had with more lever travel. With the extra bearings, these Dia Compes approach that feel. Many other brakes I find will flex and smush the harder you apply them, but the power doesn't go up as you pull the lever further.

bikemig 

Other than doing what @scarlson did, I suspect that the straddle cables are unobtanium. Dia Compe sells a modern version of these but finding small parts may be hard.

GC450 | DIA-COMPE

The part number is "1273-100 Straddle Cable" but tracking one down may be tough. Too bad as I have a set of these brakes that I'd like to get operational again.

scarlson 

bikemig I would like to test mine on my bike beforehand, but would be open to making you a pair.

I will let you know once I've taken it for a ride, if you're interested. Note also that if you're picky, mine is not exactly the same as the original and may require a slight prying-open of the slot in the end of the brake arm to make it fit because the cable itself is thicker. The originals are more like a shift cable in terms of thickness, but the ends of shift cables are universally too big so I would have to machine both ends, and I don't have access to the shop at my workplace during the pandemic here unfortunately.

scarlson 

Here I put a rack on the brake. This is the second one I made, out of the other brake in the set, for my friend's bike. This is the Gran Compe ENE Ciclo rack. It is in the same vein as those TA racks for MAFAC brakes. I am really not impressed with its construction, to the point that I regret buying one, but my friend with the Vitus has been complaining he can't carry his Berthoud bag, and this rack is all I have, so it goes on the bike for now. It is comically small underneath a full size randonneuring handlebar bag, but hopefully supports the thing ok. I only had to bend it a little to make it work. Note I am running out of hardware!! Those are nuts from V-brake pads.


The thing I dislike most about this setup is the upper mounting tang from the rack that gets sandwiched between the brake and the fork crown. This just makes the whole mounting more smushy. Having that horseshoe plate right up against the fork crown gave it some solidity, which with this system it now does not have. Under normal circumstances, I would braze the upper mounting tang to the brake bolt and cut off the excess, but these are not normal circumstances, it is not my bike (I will suffer through the quarantine with a Cannondale seat pack), and I would like to keep this reversible, with the hope of eventually tig welding a rack of a decent size out of stainless tube and selling off this rack to someone who might actually like it!

Salamandrine 

That's a very cool mod. Thanks for sharing! And it sounds like it actually worked great too, which is always a plus.

I remember when the GC450 centerpulls were the ultimate touring brake. This is just before cantilevers made a comeback. After that centerpulls were seen as archaic and old fashioned for decades. (kind of like cantilevers had been up until that point)

FWIW I have one of those little ENE mini racks too. I got it basically for free in a package deal with some GC610 brakes. I decided the best use is to convert 80s mid level Japanese touring bikes into rando style bikes, and that it's sized for a small day handlebar bags like the Ostrich F-104N, perhaps specifically that bag. I was going to try to use it on my touring bike, but decided it isn't practical for camping. Maybe in this configuration it will work well for you though. I'd like to hear feedback.

scarlson 

I paid real money for mine, so I'm bummed with how small it is, but it serves me right for not reading the fine print. It's the first time in a while that I've had that feeling like a child opening a box to find a toy comically smaller than the one pictured in the TV commercial. And that's not getting into how heavy it is. My Vitus is a testbed for new things, but it's also my weight weenie project, so it's something of a concern. But I should be able to fabricate a proper tubular rack once I get back into the lab.

It's going to be a few days before my friend can put the rack/brake combo on his Vitus 979. I handed it off to him but he's isolating it for 3 days for the lil buggers to die off before he installs it. He'll be using the huge GB28 bag, so hopefully it doesn't collapse onto the front tire! And he doesn't get a decaleur until I'm back to work either, sadly!

scarlson 

Here is the long-awaited tubular rack. I welded this from scrap 1/4" stainless tubing and stainless plate, using an Orion micro TIG welder. I have used this welder to make decaleurs, and I find it incredibly user-friendly. You don't even have to use much filler metal. I haven't done much polishing just yet, pending test-fit, but the rack came out decently straight and looks like it fits the bag well. I incorporated an aluminum booster plate into the design because the posts flex outward a frightening amount, and I didn't want that fatiguing the rack more than necessary. It is a separate piece because making it out of stainless and integrating it into the rack would be heavier and harder to make.







129g weight. In your face, Compass René Herse!


Brake's a bit of a boat anchor, though, near 191g. Many dual-pivots are lighter, and old CLBs would be about half this weight.

oneclick 

Well, you did. But it was the manufacturer's fault, you just fell victim to Shiny Thing marketing.

Ball-bearings are a terrible idea for brake pivots. They are not suited to low rpms, and they are not suitable for bearings where the movement is on the order of a few degrees, and single-row bearings are especially unsuited - they have precious little resistance to mis-alignment load, which are the greatest encountered by a brake pivot. No wonder they squeal.

An oilite journal is what you want. Make sure your bit is *sharp*.

scarlson 

I mean, I still had fun with them! Just not the kind of fun I thought I'd be having...

I've heard lots of bad jokes about the fate of the engineer who designed them. Seriously, what were they thinking, right?

Yeah, I'm not doing ANY more machining on this job. It would stop being fun. The two-row upgrade is serving me fine for now, and it was easy. They squeal about as much as Paul Racers, and stopping power is comparable. I do wonder how long until these bearings become brinelled (or false-brinelled) and notchy.
I have done some turning work with those sintered bronze oil-soak bushings in the past, for upgrading MAFAC brakes. They do require sharp tooling, that's for sure.

I like my bikes to have a central theme in their design. The theme of my Vitus 979 is "so crazy it just might work". The glued-together frame is the centerpiece to this philosophy. And then I've got a lot of '80s CNC stuff on there: topline cranks with the crazy milled-out spider, aftermarket aluminum bolts in my Cinelli stem, Biopace rings, Time TBT pedals, Cool Gear saddle, Scott Superbrake on the back. These brakes, being functional and crazy, now fit the design, which is what I was aiming at.

Charles Wahl

Would adding some toe-in using (or making, by filing normal ones) the kind sold by René Herse help squealing any?


Or is the squeal due to ball bearings instead of bushings resistant to such amelioration?

repechage

Another Saab story... I thought about a 93 wagon near the end... bought a WRX instead of a 92 Wagon.

Nice work, I always thought how did they package ball bearings in such a little volume... now I know. Thanks.

But how it the Tandem? How about a report?

oneclick 

Probably not.

The "squealing" is a result of stick-slip, which is mainly a function of the resonant frequency of the arms and the amount of excursion; if the excursion is large enough to have the pads alternate between stick and slip at a frequency both resonant and audible you hear squeal. Having pads not parallel to the braking surface only makes it more likely that the friction between the pad and the rim will vary as the pad first touches the rim with only part of its surface, then more-and-more as greater pressure is applied.

scarlson 

I don't like to toe-in brake pads a ton, because they then wear down at an angle and then you have to toe-in even more. These antique Mathausers especially, I don't want to wear them down at an angle. Hek, I don't know if they would stop the squeal, and I'm ok with a tiny bit of squeal. Nature of the beast, for centerpulls in general, I suppose. My friend Kevin, who got the other caliper of this pair, has filed some washers to toe-in his pads. He cares about these things much more than I do, and he's using Yokozuna pads that are easy to change after they get worn down at an angle.

Aye, I have had a classic SAAB 900 car ('79-'93, the real Saabs) since I was 17. Half my life. Can't give 'em up, even as they get harder and harder to maintain. Having one was my '90s childhood dream, so how could I resist?

As for the '46 Herse tandem, I am making slow progress as time permits. Often I would like to work on it, but I can't commit enough to make it worth starting. The stakes are higher with such a historic item. I want to make that perfect. The sort of hacky welding and filing and turning in this thread is much lower-risk, so it's more relaxing than working on a museum piece worth more than my old SAAB. I will work on an update as soon as I gather together enough material to make a decent update! I have some stuff, but it needs to be cataloged, photographed, and written up. Don't worry, I haven't forgotten or given up! Also I would really like to get out and ride, but my Trek's fork broke, leaving me with only the Vitus to go fast on, because my Ron Cooper isn't fast, so I really wanted to get this done so I can ride fast with my favorite handlebar bag. Even so, the Vitus isn't very ergonomic, so I want to get my Trek working. Now, to do that, I need to make a fork jig and build a fork for my Trek, and before I do that I need to order some parts. What a mess! By the time I get to ride my Trek on a nice long distance jaunt, riding season will probably be over!

Feldman

I am super impressed by the work you have put into this brake and rack! Great job!