Is this a frame drain plug?
#2
Senior Member


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From: Thunder Bay, Ontario, Canada - burrrrr!
Bikes: 1958 Rabeneick 120D, 1968 Legnano Gran Premio, 196? Torpado Professional, 2000 Marinoni Piuma
What does the removed piece look like? My first thought would be it is for adding grease but cannot really tell without seeing what was removed (fingers blocking adequate view).
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#4
Cyclotouriste


Joined: Aug 2009
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From: South Holland, NL
Bikes: Yes, please.
Looks more like an attachment braze-on of sorts to me. Rear fender? Generator?
#5
Bike Butcher of Portland


Joined: Jul 2014
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From: Portland, OR
Bikes: It's complicated.
I doubt it's a drain plug. Collecting water in a BB for later removal doesn't make sense, just use the BKM and put a hole on the bottom for drainage.
Rear fender attachment also doesn't make sense, it would attach to the chainstay bridge. Fenders curve away from the BB in that area.
Maybe a generator?
Rear fender attachment also doesn't make sense, it would attach to the chainstay bridge. Fenders curve away from the BB in that area.
Maybe a generator?
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#7
framebuilder


Joined: Dec 2009
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From: Niles, Michigan
I've seen generators somewhere that are placed in that area. They contact the rear wheel in the center rather than the side of the tire. I don't remember how they were activated. Sheldon Brown shows a picture of one in their descriptions of different kinds of generators. They note they are no longer being made and have the difficulty of turning on and off.
#10
#11
Señor Member


Joined: Dec 2007
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From: Colorado
In that case, that is the anchor point for the cable for the front derailleur.
There was a short period of time where some MTBs used a modified bottom pull FD with top tube mounted cabling.

Note: I think my pic is for the same year/model frame. I can't recall which year my frameset is, but the colors look the same as yours.
There was a short period of time where some MTBs used a modified bottom pull FD with top tube mounted cabling.

Note: I think my pic is for the same year/model frame. I can't recall which year my frameset is, but the colors look the same as yours.
Last edited by CO_Hoya; 04-08-21 at 05:38 PM.
#12
Passista


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On some MTBs the FD cable coming from the TT/ST went through a pulley to reverse its travel to work with a bottom pull FD. That looks like the mounting place for that pulley.
#13
In that case, that is the anchor point for the cable for the front derailleur.
There was a short period of time where some MTBs used a modified bottom pull FD with top tube mounted cabling.

Note: I think my pic is for the same year/model frame. I can't recall which year my frameset is, but the colors look the same as yours.
There was a short period of time where some MTBs used a modified bottom pull FD with top tube mounted cabling.

Note: I think my pic is for the same year/model frame. I can't recall which year my frameset is, but the colors look the same as yours.
#14
Mad bike riding scientist




Joined: Nov 2004
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From: Denver, CO
Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones
In that case, that is the anchor point for the cable for the front derailleur.
There was a short period of time where some MTBs used a modified bottom pull FD with top tube mounted cabling.
Note: I think my pic is for the same year/model frame. I can't recall which year my frameset is, but the colors look the same as yours.
There was a short period of time where some MTBs used a modified bottom pull FD with top tube mounted cabling.
Note: I think my pic is for the same year/model frame. I can't recall which year my frameset is, but the colors look the same as yours.
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Stuart Black
Dreamin' of Bemidji Down the Mississippi (in part)
Plan Epsilon Around Lake Michigan in the era of Covid
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
#15
Senior Member



Joined: Feb 2020
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In general, using the outer cable to push rather than the inner cable to pull is a Bad Idea. It makes the action less precise, and this is worsened unless the cable outer is cut and mounted as best it can be to minimize that loss. Of course, you loose extra points for having a U-shaped outer section with the U at the bottom, and if you don't run stainless inners you get another reverse bonus; and if you DO have all those things and you DON'T use oil then you deserve what happens.
#16
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Good idea. I had never seen that before. It is an effective way to get top pull before top pull derailleurs became available. I always thought that a pulley like a Sturmey-Archer 3-speed pully would reverse the direction, but this is more direct. Of course, it does require a braze-on.
#17
Bike Butcher of Portland


Joined: Jul 2014
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From: Portland, OR
Bikes: It's complicated.
In general, using the outer cable to push rather than the inner cable to pull is a Bad Idea. It makes the action less precise, and this is worsened unless the cable outer is cut and mounted as best it can be to minimize that loss. Of course, you loose extra points for having a U-shaped outer section with the U at the bottom, and if you don't run stainless inners you get another reverse bonus; and if you DO have all those things and you DON'T use oil then you deserve what happens.
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If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.





