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Round Downtube Shifter Mounts (on Motobecane)

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Round Downtube Shifter Mounts (on Motobecane)

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Old 07-03-12, 06:48 PM
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schroeza
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Round Downtube Shifter Mounts (on Motobecane)

I am working on restoring an old Motobecane right now and am struggling with the shifters. The mounts are welded onto the frame and look original (don't know specific model, original paint/decals are long gone), however, they are completely round rather than having the flat edges necessary for the friction based shifters I have found.

If anyone knows what kind of shifters (name, brand, anything) will work on this, please let me know.
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Old 07-03-12, 07:25 PM
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AZORCH
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Please show pictures if you can. It's difficult to provide suggestions without them, plus we love seeing whatcha got to show!
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Old 07-03-12, 09:22 PM
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schroeza
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yeah, the picture's too large to post here, but here's a link:

http://imgur.com/C6RRg
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Old 07-03-12, 09:32 PM
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seen huret levers mount on braze ons like that on an old mercier...not sure the model though
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Old 07-03-12, 09:34 PM
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Here you go:

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Old 07-03-12, 09:38 PM
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You'll find that type on a lot of old French bikes. The hole is sometimes 4.5mm instead of 5mm as I recall, and if so compatible only with some Simplex and Huret downtube shifters' bolts.

There are some products on eBay, clamp-on downtube bosses, that feature the modern standard bosses with the flats and 5mm holes, which is what the whole industry adopted once indexing became universal.

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Old 07-03-12, 09:50 PM
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With brazed-on (not welded) DT shifter bosses like that, the first part that goes on is a washer-like fitting with a square hole. It typically also has a side flange with a notch into which fits a tab on a washer that goes on after (i.e. outside) the lever, to provide anti-rotation for the outside washer and adjustment bolt. If you had all the pieces you would see what I'm talking about. It's pretty obvious. IIRC (I don't have parts in front of me at this time) you should be able to use pieces from clamp-on shifters by Huret or Simplex, provided it has the same boss diameter. The clamp-on arrangement had bosses just like that, a square surface from which protrudes the round stud.
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Old 07-04-12, 08:24 AM
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This might be what you are looking for, this is from the "non-bossed" side lever assembly.



and the clamp on with the other shifter still installed on the side with the brazed on boss...


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Old 07-04-12, 02:50 PM
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Simplex Criterium shifters will fit your bosses. The above shifters are crap and will break. You obviously have bosses on both sides. I don't think anyone but Peugeot used the single boss

http://velobase.com/ViewComponent.as...m=104&AbsPos=6

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Old 07-04-12, 05:08 PM
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This Gentleman may be the ultimate Poser or Fred!



Unless he intends to buy a round for the bar he should atleast remove his helmet.


OH RIGHT the shifter bosses. Will shimano backing plates fit on those? The OP may have to get a 5mm bottom tap but if the shimano sifters will fit it may make things easier for him.
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Old 07-04-12, 05:15 PM
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Originally Posted by Bianchigirll View Post
This Gentleman may be the ultimate Poser or Fred!




The leg muscles would indicate a non-poser, perhaps?
The helmet however, cracks me the hell up ahahah.


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