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Strange rear brake bridge hole

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Strange rear brake bridge hole

Old 03-29-17, 05:18 PM
  #1  
BobLoblaw
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Strange rear brake bridge hole

I have a late 70's Olmo with a brake bridge mounting hole that has a mushroom extension...it stick out the back of the brake bridge pointed towards the seat tube. The brake bolt has to go all the way through the brake bridge and the mushroom, and the one on the DA 7400 brake I have is not long enough to pass all the way through this strange beast.

Any ideas? Different brakes? Can I get a longer bolt for the brake I have?
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Old 03-29-17, 05:21 PM
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Gotta have pic's, especially with the word "strange" in the title.


Originally Posted by BobLoblaw View Post
I have a late 70's Olmo with a brake bridge mounting hole that has a mushroom extension...it stick out the back of the brake bridge pointed towards the seat tube. The brake bolt has to go all the way through the brake bridge and the mushroom, and the one on the DA 7400 brake I have is not long enough to pass all the way through this strange beast.

Any ideas? Different brakes? Can I get a longer bolt for the brake I have?
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Old 03-29-17, 07:13 PM
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I have no idea of what you are talking about but if it needs to be longer how about another front brake?
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Old 03-29-17, 08:33 PM
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Look at it again and think about whether it's possible that it's designed to provide a wide, flat base for mounting the brake forward of the stays.

That wasn't common, but not rare either back then, and if so, would be for a brake predating the recessed mounting hardware and shorter bolts they used.
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Old 03-30-17, 08:50 AM
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I believe this is the bike in question.....



I think it is for nutted brakes.
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Old 03-30-17, 09:05 AM
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If it's like the one in the pic it should take a medium length nutted brake with flat mounting washers.
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Old 03-30-17, 09:16 AM
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I had the same protrusion on the brake bridge of my Italvega. On the back there was the tube used to reenforce the hole sticking out. I took a concave alloy washer and drilled the hole wide enough to slip over it. That provided a stable area for the bolt to be tightened down.
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Old 03-30-17, 09:17 AM
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It sounds like a brazed-on flat for the mounting bolt nut, so you don't need the milled washer supplied with exposed, hex nut brake calipers. I've seen a few bicycles with this feature. By the time of 7400 most high grade bicycles had transitioned to recessed Allen nut mounts which use shorter brake bolts.
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Old 03-30-17, 09:26 AM
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BobLoblaw
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Thanks everybody! Looks like I'm in the market for some brakes.
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Old 03-30-17, 09:40 AM
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Old 03-30-17, 10:33 AM
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Mushroom?
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Old 03-30-17, 11:58 AM
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Old 03-30-17, 12:05 PM
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Anyone have a brake bridge like this? First one I have seen.
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Old 03-30-17, 12:08 PM
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Originally Posted by juvela View Post
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Old 03-30-17, 03:52 PM
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Originally Posted by guygadois View Post
Anyone have a brake bridge like this? First one I have seen.
Yes, as I said in post above, my early 70's Italvega has one.
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Old 03-30-17, 04:33 PM
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Is the hole large enough to use a recessed nut (sleeve nut)? If it is your current brakes may work fine.
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Old 03-30-17, 05:04 PM
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Yup, Go Find a longer bolt and regular nut, Brake.
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Old 03-30-17, 05:16 PM
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Many 70s frames that didn't utilize concave washers to ensure a flat mounting for the brake used this setup - in fact, all my early Colnago Supers (both '73s and the '78) have this feature. It's really not that uncommon.

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