Mafac brakes different lengths?
 

I am finally reassembling the 1970 Gitane Tour De France That I started last summer. After finding frame damage and getting it repaired I painted it and installed the decals and now am re installing the hardware. The bike originally was spec'd with 27" wheels and Mafac Racer brakes . I am using 27" Mavic rims and 1"Passela tires and when I installed the beautifully polished Mafac Racers they didn't fit. They are too long. They would probably fit using 700 c tires but definately won't using 27's. I happen to have a set of Mafac Competitions and they do fit . I am confused. I have built up quite a few bikes with 27" wheels using Racers. Generally they will fit 700's if you slide the shoes all the way down. I have never encountered a situation where they are too long for the 27's. Did Mafac make Racers with different length arms? Are the Competitions' shorter or did they make them in different lengths also?

The bike is a stunner. I can't wait to get it all finished and post pictures.

Both Racers and Competitions were produced with stirrups of varying lengths. The arms are fixed length and the overall reach is determined by the stirrup.

see here

Note that “adjustable reach” refers to a stirrup with a vertically slotted mounting bolt hole.

MAFAC Brake Reach - Gitane TdFs & SCs
 

Perhaps la police française des spécifications du vélo were busy at la boutique des croissants...

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...or the frame brazers at Gitane drank too many "happy meals" at Chez Mac for lunch!
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A while back I had over half dozen 1969-1973 Gitane TdFs and Super Corsas in house. I checked and compared the geometries on them.

The earlier ones, pre -1972, had fork blades with smaller diameters at the fork ends plus the bend radii were about 75% from the bottoms.

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The later ones from ~1972-73 had larger blade diameters at fork ends and slower bend radii that went up to about 60% of the blade lengths.

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They all had the same fork rake distance ~50mm.

Problem was the fork blade lengths varied which created problems with brake reach. (blanc ou rouge lunch) Most of those models from the Mylar® foil decal era shipped with sewups which were 700c size wheels. Some of those bikes may have been equipped special order from the Gitane factory with clinchers but in all likelihood they would have had 700c tires which weren't commonly available in the US at that time.

Depending on availability and the importer's mood, TdFs and SCs were sometimes available in the US on special order from Mel Pinto Imports (MPI) the primary US Gitane importer from the mid 60's until 1973. They had 27 x 1 1/4" clinchers. There was an added charge for those bikes.

We were told that MPI switched the wheels at their warehouse in Virginia. I may have seen 1 or 2 TdFs that came with clinchers from MPI back then. They used these 23.5mm wide Weinmann alloy rims with Campy Nuovo Tipo hubs. MPI may have even built them in house.

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Getting back to MAFAC brakes, Gitane used Racer model brakes on those top bikes up to 1971 when Competition brakes started being used. The Racers were "standard" reach while the early style Competitions were short reach.

MAFAC Racer brakes where introduced in the early 1950's and continued to be produced into the early 1980's. DURAL FORGE was stamped into the outside caliper faces until ~1969 when it was changed to the model name RACER. Racer brakes were made in 4 different reaches: 43.5mm to 58mm were the shortest reach with 55.5mm to 75mm the longest.

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As "racing" bikes with sewups became more common and popular in the early 70's the clearance between the small 20mm-23mm cross section tires and the undersides of the fork crowns and rear brake bridges became less because there was no need for fender clearance on those competition oriented models. That called for short reach brakes.

The first generation Competition brakes had a brake pad adjustment reach 44mm to 54mm with an addition 4mm to 5mm up or down adjustment using the elongated brake bolt mounting holes in the bridges.

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Competition oblong mounting bolt hole.

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I had to file the hole an additional 6mm (1/4") to get the front caliper high enough on my all original 1971 TdF for the pads to properly contact the sewup (700c) rim. I also had to elongate the pad adjustment slots a little.

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27" rims are 8mm larger diameter than 700c rims. They sit 4mm higher so a 27" wheel even with a 1" tire would probably not clear the bottom of the fork crown.

Reach problem is not necessarily the fault of the MAFAC brakes... They came in different reaches and it can be difficult to find the proper size with almost 50 year old brakes especially at a time when component shortages and the demands of the short lived Bike Boom Fad caused bike makers to use whatever they could get.

les spécifications sont sujettes à modification sans préavis

capnjonny I hope this helps a little.

The 1974-75 model TdFs came with 27" clinchers...

Also there's a fantasy vision amongst some (sugar plum fairies danced in their heads) that Gitane Super Corsa models were available with Campagnolo side pull brakes. Yes they were in the price list and few Super Corsas came from the factory with them but Campagnolo components, especially brakes were never readily available in the US until early 1975 after the bike boom had come to s screeching halt and Campy's production could start catching up with demand.

Campy brakes on most Super Corsa with were installed by Mel Pinto, bike shops or owners. The going dealer price for Campy brakes was ~$129 to $179! That pushed the price of a Gitane Super Corsa up into the range of a top quality Brit or Italian all campy bike bike!

verktyg :50:

Chas, and anyone else who wants to chime in
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https://cimg7.ibsrv.net/gimg/bikefor...4d547a85cb.jpgI consider you the authority on there bikes and I wanted to send you some pictures of the current state of the project and ask your advise .

I have been trying to stay original on this build but not sure about a few details and want your opinion.
I have a pair of half hoods and original levers but the ones I put on the bike look so good I want to keep them. Do you know by chance what they came on originally?
I have a very nice Simplex down tube shifter on the bike. It works great and will keep. I also have 2 delrin piston type Simplex front derailleurs. One has a mint body and rusted cage the other a faded body and mint cage. Alternatively I have a very nice Huret front. Not sure if I should try taking the Simplex units apart to make one "perfect " unit or use the Huret instead. Lastly, I originally fitted some 27" rims and found that the Mafac Racer brakes were too long. I fitted a pair of Mafac Competition's and they work with the 27's. Then I read your post saying the bike would have come originally with 700's . I heaved a sigh and took down my prized 700c Super Champion rims with Campi Hubs and fitted them with new Michelin gum walls. They work with the "Racer" brakes without the hassle finding straddle cables. I also intend on fitting a Crane GS rear derailleur to go with the 14-32 Suntour freewheel (It's hilly around here and I hear the Eroica rides have some long climbs). It looks like I have to tap the dropout for the derailleur mounting bolt. Can you tell me which tap I need. Other than taping the hole is there any other mod I need to make for that derailleur?
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Anyway I would welcome your input on some of these choices. When the bike is finished it will be sold by the Silicon Valley bicycle exchange , Hopefully as a package along with the 1969 Gitane mixte I just built up . They are both painted Rustoleum Tuscan Sun and hopefully some fan will Just have to have them.

Don't use the Simplex front mech - it'll break. They ALL break.

The Huret will work better as well.

Mafac Brakes too short
 

Hi, I have the opposite problem, Mafac brakes too short for my Peugeot frame and 700C wheels.
maybe we can exchange our mafac brakes?
I can’t send photos, this is my first post, and I need mínimum 10 to do it

I ran into the exact problem with 27” wheels on my PX10. The solution is a Mafac brake that use a bridge labeled “451.” These place the posts closer the center mount.
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I've always found MAFAC's solution to short and long reach centre-pull brakes to be fascinating. There are definite advantages from a cost and logistics perspective, as you you only have to manufacture and stock one extra part, as opposed to two. I suspect this is what drove the concept in the first place.

However, it introduces another significant change. In a traditional centre-pull caliper, longer arms have less mechanical advantage. With MAFAC, the mechanical advantage of the arms does not change. To change the mechanical advantage, you need to adjust the yoke cable length. This can sometimes be disastrous in the hands of a newbie, who doesn't understand the relationship. However, in the hands of a knowledgeable mechanic, it provides the ultimate in tunability.

Just an idle thought - someone like Paul could make stirrups in various depths and widths. For perhaps a Renee Herse or the like to carry. With that availability and replacement stirrups and bushings, we fans of Mafac RACERs can keep them running many more years. (Those caliper often outlast bikes simply because they are so much less crash damage prone. I've never tracked total mileage on one of those calipers but I have certainly piled plenty on a few. (Maybe three pairs and a pair of cantis over the 85k of my fix gear commuters' lives and still going strong. I don't recall ever throwing them away and I don't have a box of dead ones.)

I picked up a set of Competition brakes that have some reach adjustment, via the vertical brake bolt slot. It allowed the rear brake to work when I needed 61mm of reach.


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Thank you, I've already order a pair of Mafac Competition to see if it is enough. Otherwise I'll try the "451" solution given by Nmvlvtmr