cudak888 

Gotcha!

Humor aside, since not everyone has seen the ongoing discussion in the mafac stiffener thread about these, I thought I'd spin this off into a separate discussion.

Given the elusiveness of the Spence Wolf / Cupertino aftermarket Mafac bridges from BITD, I decided to try a test run of a modern interpretation / repop. These arrived in the mail yesterday, to the specs I came up with (with the assistance of bulgie, Charles Wahl and oneclick ):



Now, the company I used to make these isn't my first choice, so I'm on the fence. One bridge clearly has a few scratches on it, and - unlike my normal laser cutting service which will deburr things, these folks don't (thanks @bulgie for the tool recommendations).

I realize this is not really anything to complain about, but it's just one more repetitive, irritating thing I have to put on repeat for every one of these things after paying a fair amount to get them cut in the first place.



Still, this company will laser etch the stylized "M" and the other won't, and I feel this does make a big difference. The end result does a fantastic job of transforming an otherwise homely Mafac Racer:





Next step is to pull something from the fleet that I can fit these onto for testing. I don't have much here that's still centerpull; might have to make the '61 Paramount the testbed.

More to come.

-Kurt

scarlson 

The security torx screws assure that nobody will steal them!!

Seriously though they do look nice!

Mr. 66

With tork security bolt! You're not messing around.

I have a sheet of 6160 I've been thing of making a Soma long cage knock-off, or a canti stiffener with.

Charles Wahl

Very nice! It's a shame that when such a useful device is installed, it obscures the original brake.
Is that 1/8" / 3 mm material?
Is the logo "laser etched" or "laser marked"? (which are different processes, according to a local outfit I've been considering using for some other work)

cudak888 

That's what happens when you wind up hoarding all the bolts removed from these retired share bikes. So long as I don't mind security Torx, I have M5 and M6 bolts to last me a while



Plus point: The washers are captive to the screw. Can't lose them.

Someone here on the forum - it might have been rootboy, but I don't know for sure - tried making a long-cage Rally repop cage long before Soma did. The one flaw is that the mounting threads are super fragile with most aluminum alloys at that width; one of the reasons most manufacturers swedge a steel bolt into aluminum cages. Mine stripped immediately on installation.

This is 3.2mm 5052 aluminum. Ideally, I'd like to get it in 6061 or 7075.

I could get very creative with the design - full drillium if I wanted - but I personally can't stand how rough the Racers, early Competitions, and Raids look. To me, it's a visual improvement, even fi it looks a bit more Modolo than Mafac.

The company I had these done with claims it's "area engraving," but it's clearly not really engraving at all. I'll ask them when I inquire about the scratched piece.

-Kurt

SurferRosa

My question for the op: is this the real "is this a real Mafac stiffening bridge or a knockoff" thread or a knockoff?

79pmooney

With those security torx bolts, these things are as far from "knockoff" as you can get. Knockoff hubs for cars, wing nutted hubs for bikes ...

tiger1964 

Hmm, hide the OEM Mafac text on the caliper and add a Campagnolo logo to the accessory brace?

cudak888 

It's the real knock-off thread about the knock-off bolt-ons.

Speaking of which, would you kindly fetch my Series 1 XKE?

Been there, done that




-Kurt

Drillium Dude 

Dayum, Kurt - those came out really nicely (doffs imaginary helmet... wait, I don't wear a helmet - make that cycling cap)!

Well done; I'm sure they'll do the job, too

DD

Charles Wahl

"Rough" is OK with me when it's "authentic" and "vintage".
That sounds to me like what the joint in my area calls "marking" as opposed to "engraving". I've never seen the former, and recognized it as such. My interest in knowing the difference is that I'm trying to make an amplifier control panel with one or the other.
Sacré bleu! NE JAMAIS! or should it be NIEMALS! NIEMALS! NIEMALS!

nlerner

I wonder if there’s some crude way to quantify the effect of this stiffener, compared to a MAFAC Racer without the stiffener. Maybe @gugie has some engimaneering know how to impart.

gugie 

Gugie doesn't trust everything he thinks. I'm an empirical guy, and I do have a few bikes with MAFAC brakes I could try a stiffener and report back. Some of them definitely squeal like a pig. Won't be anytime soon, I'll put it on my post-retirement things to do list.

tiger1964 

OK, WHERE do I order a set of those decals**********?

cudak888 

Having not that much experience with Mafacs myself, I'm now wondering whether I should test them with the original rock-hard pads, or with Kool-Stops. The KS pads shape-shift a lot more when applied though, so I'm not sure what setup will give me a good baseline.

Their looks is one of the reasons I've only put Racers on one build after 15+ years, even though they're nicer to set up than any Weinmann 999 and feel better too. I've tried to stay away from them because of their looks, so this is one component I - personally - don't feel bad tinkering with for overall appearance.

It's dead flat, I'm pretty sure it's the laser marking you speak of - such as letters on an aluminum faceplate for an amplifier or lettering on aluminum-bodied lighting equipment. I wouldn't classify it as "engraved" at all by definition of what engraving actually is.

I'm pretty sure that was a Dia-Compe, so Japanese may be more appropriate. But the forum prevents me from having fun with kanji spit out of Google Translate.

Would you like one to play with, Mr. Butcher, sir?

If I told you, I'd get banned

-Kurt

dddd

I haven't tried adding a front bridge to any Mafac caliper, but I have noticed that some combination of their good leverage (and an amount of flex coming from somewhere) combines to give the brake lever a long throw through its generous travel range. These Mafac brakes also manage to give good clearance at the pads for handling warped rims and wheel flex.

I did find it necessary to explore improving the flex resistance of the Weinmann front caliper that I used for MTB racing, due in part to my use of slippery-when-wet MA40 rims with still-intact anodizing.

I first made the front bridge, only tall enough to clear the biggest (45mm) tire I would use. It made the brake feel a lot less less squishy at the lever, good for keeping the lever from bottoming on the grip.
I then noticed how much that the long-reaching arms and pads rotated as they got pushed forward by the rim, the long Matthauser pads threatening to have their top-front corner cut into the tire, and much of the rear of the pad moving past the other edge of the brake track toward the hub.
So I added tethers to transmit the braking force directly to the fork instead of cantilevered off of the flimsy, nylon-bushed pivots.
The latter modification surprised me, it firstly reduced friction at the pivots quite noticeably, but also kept the long pads better aligned with the rim for added firmness at the lever.
The tethers also angled slightly inward toward the rear, so effected some self-energizing effect as well.

There are examples of both modifications on bikes from earlier in the last century, and we also saw brake boosters as they became called become somewhat of a fad back in the 90's on mountain bikes.

Crafting a booster/stiffener plate for a particular bike is a fun exercise in practical design, more fun when you add some precise drillium to top it off.
On one of my efforts (on the front of a hybrid), I used a ready-made booster having big hoops for eccentric bolt-center adjusters. But it was so much taller than necessary, being made for 26" tires. So I hacked off the loops and notched the ends of the horseshoe to position it against the cantilever pivot bolts with thick sandwiching washers holding it in place.
Then I made one from scratch for the rear, adding drillium. The braking really is so much better, front and rear, especially since the pads no longer go through such a range of toe-in change due to flexing pivots.

My first-ever brake booster was the strip of bracket cut off of a water bottle cage, modified a bit for use on a 1978 U09 having Weinmann centerpulls.
It (the bracket) sure was ugly! That bike has been sold and thankfully no pictorial evidence of that booster remains.

cudak888 

FYI, I asked and they confirmed - it's Cermark ceramic marked / sintered on the surface.

The more the arms can bend between the pad and the mounting point - whether it comes from the bridge, the arms, or the slop in the bushings - all can contribute to chattering if the pads can momentarily reduce effective friction against the rim. I don't think the bridges were necessarily invented for that as much as creating a bit more lateral rigidity to the mounting posts/bolts. But I may be wrong.

I'm curious how the bridge helped reduce the sponginess; might I ask what's the OD on the spacers you used to push the bridge further forward? I'm wondering if the bushing and the bridge helped to apply more pressure around the nylon bushings, taking some of the bendiness out of it. I wonder if the bushing/washer alone spreading the force might do the same thing, minus the bridge. Just spitballing ideas here.

I think it can't be overstated that you're running that on a Pedersen replica, by the way. That just makes it cool. It's even cooler that you're using it on one of them.

Those tethers - in principle - remind me of the L-shaped brackets fitted to some bikes (usually cheap ones, but I've seen them factory with John Bulls on secondary-brand Raleighs) to grab the stays/fork blades to stiffen the caliper. Always thought of it as a kludge; by the 1960's we knew how to build a half-decent brake that didn't necessarily need these.

Mind, the tethers look absolutely perfect on the Pederson though. Adds an air of the past to it.

-Kurt

AdventureManCO 

whew I’m glad you cleared that up!

cudak888 

I took your advice




-Kurt

mpetry912 

Kurt you're doing some very nice work ! A pic of the original which were also laser cut, and then drilled.

There was some spalling from the cut and that was removed with conventional methods :-)

I like these and they do make a difference in brake "feel". to round out the package, I'd suggest a new stainless center bolt and brass bushings, both available from Rene Herse Cycles.

very cool !

/markp

Piff 

Fantastic work! Any idea if these would fit gran compe 610s? And if you'd ever consider selling them?

cudak888 

The holes in this case are also laser cut. A bit of a cheat, but it saves me a lot of time.

Unless the GC610 shares an identical bolt spacing to the Mafacs, it won't be possible. Any design for Weinmann, Dia-Compe, or Gran Compe centerpulls would also require spacers to clear the front arm.

I'm sticking with Mafac right now. All I have to do to get these ready to sell is deburr the reverse side. I'd be out of the notion if I had to start sourcing additional hardware; this stuff is expensive enough as is.




-Kurt

52telecaster

My rear raid got to where it won't hardly squeal at all, I kind of miss it. Also these things stop better than any brake I ever used.

mpetry912 

You do know what MAFAC stands for right?

Mon Accoutrements Fait un Atroce Cacophone

(translated - my accessories make a terrible sound)

Kurt - let the end user do the deburring ! Good for you for getting these made

/markp

cudak888 

As much as the crude castings of Mafac Racers don't really appeal to me, I was greatly impressed by their feel on my Raleigh Competition when I had them on it.



Now that I've made these bridges, I think I can hack the look of a Racer now too

Ils s'arrêtent toujours mieux que les Weinmann ou Dia-Compe.

At least, I hope Google Translate got that right.

I'm not sure how many people would consider these if they had to deburr them on their own, really. I just wish I had one of these:




-Kurt