mboro1876

I've just got some Racers and I loved reading through here, but can't quite discern what is the full detail of the "best set up". So far I get:
-- toes in by cold setting with a wrench
-- straddle cable lower for more MA (but how to know when more MA is needed?)
--...
Beyond that, I don't know what to do with all the other possible adjustments. Is it summarized somewhere?

jimmuller 

Before you do anything, just install them and try riding. Maybe you don't need to do anything!

non-fixie 

+1. I was just about to type that. I have used MAFAC brakes on most of my builds and have never bothered much with setting them up. I use the original pads as well on all of them. Some squeal a bit in the beginning but that usually stops after a while.

mboro1876

they're not bad so far, but still have the original pads -- will hold off until some kool stops arise before going further then

brokebottom

And an anvil

Salamandrine 

Yeah, just put them on and ride. Any toe in will disappear shortly as the pads start to bed in. If you're worried about squeal, get the Kool Stop black Mafac pads. I have them and they don't squeal at all. Stopping power is as good or better than original Mafac pads. (when they were new 35+ years ago...)

WRT to straddle cables, I usually set the front brake with a slightly shorter straddle cable than the rear. I would suggest avoiding extremes in length. While you can technically get more mechanical advantage with a really short cable, IME center pull brakes start to act funny if you make the straddle excessively short. They start doing sort of an on/off thing, and if you squeeze harder, nothing happens.

Anyhow, my preference is about a 90º angle in the front saddle, and slightly more acute (longer straddle) in the back.

mboro1876

the guys who have used the slide in replacements: do any of you do this in situ or is it unavoidable to remove the pad holder (10mm wrench I think...) first?

palincss

NO!

That's downright silly. https://www.compasscycle.com/shop/co...e-washer-pair/ $9

John Nolan 

Didn't know about those Compass washers. Great!

El Chaba

I have always taken them off to get the best access. They can slide right out or they can be stubborn, and I'd rather not push and shove against the whole mechanism and then have the pliers take a nice chunk of paint off of the fork or seattube when the pad gives way...

mboro1876

gotcha, glad I didn't try it on bike, they were stiff as hell. The new ones inserted with a few firm taps. A bit annoying trying to find the same post position on re-installation -- mine are further out from the rim now than they were, but I'm reluctant to undo them again and lose the relatively good angle and centering .

El Chaba

If you have Mafac brakes, here is something that you probably didn't know about, but now that you do should probably have one. Back in the day, Var made these, but outside of France very few people knew about them. It's a wrench that fits over a Mafac-style brake shoe that enables you to hold everything in place in the multiple planes of movement while you tighten down the nut. It's a great tool that has the potential to prevent quite a bit of cursing and swearing. In any event, Grand Bois has made a modern version...

tiger1964 

That is so cool; alas, I just looked on-line, saw "discontinued" and "out of stock", I guess if one has a drill press one could be made up as a one-off.

Salamandrine 

IF the brakes are already properly adjusted, you should do it in situ if possible, just to make it easier. If the brakes are part of a new build and need to be adjusted anyway, take them off. If they are really old and stuck, you may need to take them off. Removing the pad holder is not actually a big deal. If the brakes haven't been rebuilt in a long time (or ever), you probably should take them off regardless just to clean everything and grease the threads.

63rickert

The Compass washers can be copied in moments using original equipment washers and a small round file. That is why those washers are so thick. You can find filed washers on many old French bikes.

About front cable hangars - Mafac part 65 is a stout piece of steel. In 70s it got a little thinner, if the flex really concerns you, drill and tap for a setscrew and turn the setscrew against the headset. Then there was a strap hangar made from grey potmetal, very thin. Probably not a Mafac part at all. Appeared on a lot of entry level French bikes and too many midrange bikes. If it is too thin and cheap to imaginably take a thread and hold a setscrew do not consider it as OEM and period correct. It is junk. Any replacement hangar is better.

noglider 

I hold the pad holder with an adjustable wrench while tightening the 10mm nut.

There is nothing wrong with cold setting the arms for toe-in. I've done it hundreds of times with no ill effects.

bikemig 

I dunno, those washers look great but at $18 the pair and $7.45 shipping, I'm with @noglider, I'd rather save the bucks and bend the arms or file off part of the washer per @63rickert.

palincss

Bending the arms is the very last thing you should be thinking about. File the washer, make your own grooved washers, whatever - it's all good, but you should not bend the arms.

bikemig 

I've done it before many, many times. But I agree that filing the washer is the better course of action.

bikemig 

This is cool.

jimmuller 

Wow, pretty neat. I've always used channel-lock pliers. That seems to have worked too but getting the jaw spacing right is a bit inconvenient.

noglider 

What do y'all think is wrong with bending the arms?

Salamandrine 

It may surprise some people here, but bending caliper arms was how it was done before the days of concave washers and what not. "Cold setting" we used to call it... At any rate, as long as you don't get all crazy with it, you are not going to bend 6061 anywhere near its fatigue limits doing this. As often as not, this was done to correct reverse toe in (toe out?) on production brakes.

It doesn't take much to toe in a pad. I rarely put more than about .030" gap at the rear of the pad. If it still squeaks you've got other issues.

jimmuller 

I have found that brakes may squeal on rim I haven't ridden in a while. Maybe they build oxidation or something. Eventually the squealing stops.

79pmooney

Random Mafac Raced (and canti) experiences:

I loved the old pads (some of the time). Dialed in right, I could do a real stop close to quietly but go a little harder and let out a squeal heard for blocks. A real tool for Boston traffic that I used many times. (Car cuts you off. Squeal like a banshee! Point at the car, Every head around will swivel to you, then follow your point to the car. About that time, the driver arouses from his stupor, only to find everyone is looking at him. Drive slinks off like a bad cat.)

I currently have a newish pair of Racers on my two rain/winter/city bikes, both as front brakes. (I just replace the rear bolt with a decent quality hardware bolts.) Weinmann or equiv as rear brakes with the same treatment. (Most centerpulls are a lot firmer but have less power. Firmer means they feel virtually the same as the front Racers using full length, trouble free and paint scratching free cable.) I use Tektro levers though as a poster above said, they really don't care what you use except the levers have to have enough travel before hitting the HBs or you will be in for a nasty surprise if it rains.

I used to say you could get near brand new Mafacs and hardware for $50, but you had to remove and dispose of the Peugeot UO-8 attached. No longer true. Folks now value those bikes. But they came on many other French bikes as well and lots got taken off for "better" brakes. The parts boxes at shops still work. Look for pivot play. As long as it is small, the calipers have a lot of life left in them (and they will stop you securely long after the play drives you crazy). Bronze bushings are better than the red plastic bushings. Folks still make replacement bushings, so they can be rebuilt.

As said above, Kool Stops work well. Better hangers, especially in front improve them a lot. (Old Schwinns had heavy, clumsy hangers that are rock solid and work really well. Other bikes of the day had I believe the same hangers. Check those parts boxes. Thank you, sexy sidepuls!)

And the cantilevers - I had the Mooney built for them. First winter I rode down Alba Road above Santa Cruz, CA n a winter storm. HTere were sheets of water running across the road. Alba Road drops 2000 feet in 4 miles. Tight turns that I had never seen before (and with very wet glasses, I could barely see than). Index finger only braking worked the first half, then I had to go to two fingers for the rest. Doesn't get much better. I did pull them off and put early '80s Shimanos on. ShImano clearly copied the operating geometry from Mafac, but did a much nicer job for all the rest. The Mooney's Mafacs then did 27,000 miles on the commuter the Shimanos came off. (I probably came across a pair with newer pivots so don't quote me on the miles.)

Ben