Stevensb 

As the title says, I want to install Mafac Racer brakes on a mid-70's Moto Grand Jubile with a Stronglight Competition Headset. My concern is that the steerer tube is not long enough to allow safe installation so please bear with me as I show a couple pictures and a poorly drafted sketch of what I am looking at.

Picture one: headset without hanger
Picture two: headset with hanger
Sketch, with apologies for hasty drawing.

My concern is that with the brake hanger in place there is only about 3 mm engagement of the top nut compared to the 6.25 mm (top of "spacer" to top of steerer tube) without the hanger.

To gain a few more mm of engagement for the top nut are there narrower brake hangers or "spacers"? Or any other solutions to facilitate CP brakes?

Thanks.

Brad

Sir_Name 

How many threads are engaged within the top nut? The post would imply that 3 out of 6ish are in play, but I'm not sure that's enough for comfort over the long haul - feels iffy considering years of road noise at the threads.

rootboy 

That doesn't look too good to me. That hanger does look awfully thick. Seems I've seen thinner ones but can't put an exact on that.
I think the original that came with my Racers is thinner.

fender1

Do you have an original MAFAC front hanger? It might be a bit thinner and allow for another thread or two to engage.

fender1

Great minds and all that!

gugie 

Can you get a vintage MAFAC hanger? They're a bit thinner than the one you've got. I just ran out to measure one of mine, they're 2.5mm thick.




Another solution is from Problem Solvers



Search for "problem solvers hanger quill stem"

EDIT: looks like 2 of you beat me to it! @fender1, @rootboy, the collective mind of the C&V borg strikes again!

rootboy 

That's a pretty cool little problem solver there, Gugie.

Salamandrine 

That problem solver would solve the problem. You may also be able run a noodle of some sort from your stem/handlebar bolt. There's also stems with cable stops, but that one may be french. Been a long time since I worked on motos - can't recall.

You don't have enough threads with that cable stop. Don't do it. It does look really thick. Mafac ones are thinner but I still think it won't be enough.

Another route would be to replace the headset with a new one that has a lower stack height. That might be the most elegant solution. (by this I mean one with a thick lockring you can pull out and sub with the hangar)

eschlwc

would've thought that bike originally came with center-pulls.

Salamandrine 

Seems like there was a year or two that they came with weinmann sidepulls.

My first inclination: keep the sidepulls.

There's one more way but it's kind of extreme and personally I don't recommend it: pull the headset and mill down the head tube top and bottom by 1mm each, maybe one more off the fork. Reinstall. Requires a shop that still has their old headset mill.

Vintage_Cyclist

This is going to sound Rube Goldberg-ish, but how about using a fork crown cable stop.





If you installed an upward rising strip of metal (2 holes) between the brakes and the fork crown, you could bolt the stop to it.

gugie 

Hey, I've got a headset "mill". We called it a headset facing tool, though.

gugie 

Another solution!

Stevensb 

Thank you all. Definitely some creative solutions here. Not sure which direction I'll go. I was surprised the bike wouldn't easily accommodate centre pulls as the '74 catalogue specs Weinmann centre pulls (I believe this is '74 frame).

Brad

Vintage_Cyclist

Here's another Rube Goldberg idea, if your stem's clamp doesn't have a recessed nut to attach the bars. Use a Surly rear cable stop. You could widen the top of it to fit around the bolt, between the nut and stem. It would hang down about 5cm and could be bent into position.

gugie 

You know, that's a brilliant idea! Wouldn't be very good for a long stem/short head tube because of the extreme angle, but I like your thinking out of the box!

gugie 

Here's another idea:

79pmooney

A headset that might work is the $8 OEM Tange headset. I say "might" because it is far from a given that they ever made those headsets in French dimensions. They are easy to find in more common sizes. They have an unusually low stack height. One of the things that allows that is they have no seals whatsoever. You can see the bearings. I have used them packing the bearings with LOTS of marine grease, the stuff auto parts stores sell for boat trailers. If you can find one, buy it! You may find the top bearing (which sees little road dirt) is the answer to your problems. Despite the price, the bearings and overall quality are quite good. The top should outlast even a very good bottom and your bike will not care that they do not match.

Any good shop should have a QBP catalogue and be able to look them up.

Ben

Salamandrine 

Or just try to find a Stronglight P3 for a non ripoff "vintage" price. That's the one with a flatish knurled lockring instead of octagonal. IIRC the stack height was 3 or 4 mm less than the later P4, which is just enough for you, hopefully.

gugie 

Hey, lots of options here.
@Stevensb, let us know how it turns out.

eschlwc

if these center pulls you want to use will reach your rims, and the only issue is the tall headset stack height for your french steerer (assuming it's not an iso replacement fork), it seems the best solution is to reduce the height of both the cable hanger and serrated washer. finding a skinnier hanger should be simple enough. (the mafac one needs a stepped ferrule as well.) but finding a shorter serrated washer will be a little more difficult. i might try to machine the one you have now to trim 1mm or a bit more from it.

CMAW 

verktyg 

Your Grand Jubile had either Weinmann 999 or Dia-Compe center pull brakes.

The early 70's Grand Touring model came with either Weinmann or MAFAC brakes. Other than that very few Motobecane models had MAFAC brakes until the late 70's.

Grand Record and Le Champion bikes used Universal brakes until 1974-75. After that Grand Record models had Weinmann center pull brakes until the late 70's.

In 1975 Le Champions switched from Universal Mod 61 center pull to Universal Mod 68 side pulls. The 1977 bikes came with Campy side pulls.


While it doesn't look that way, Weinmann front brake hangers are less than 2mm thick.



Don't know why the steerer is too short, maybe some bike butcher filed it down instead of using a spacer??? You should have at least 5 threads of top lock nut engagement, other wise the headset will keep loosening up.

All is not lost!

I HIGHLY recommend that you have the head tube and fork crown refaced by someone with the correct tools who knows how to use them. That makes adjusting the headset a lot easier. It's easy to pick up 1 to 2 millimeters of stack height.

BTW, Stronglight V4 Competition headsets were very good. In over 40 years, I've only seen 1 or 2 that went bad.

verktyg

Chas.

rootboy 

Except for the early 70's Champion Teams that came stock with Campagnolo brakes.

I think that Weimann hanger is the one I was thinking of, Chas. Is it, sort of, stamped…with a recess on the underside?

rootboy 

That one is just too cool.
But when I see something like that posted,
it is invariable not for sale.