Go Back  Bike Forums > Bike Forums > Classic & Vintage
Reload this Page >

Is this a frame drain plug?

Search
Notices
Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

Is this a frame drain plug?

Thread Tools
 
Search this Thread
 
Old 04-08-21 | 02:39 PM
  #1  
Thread Starter
Full Member
5 Anniversary
 
Joined: Oct 2020
Posts: 421
Likes: 331
From: Portland
Is this a frame drain plug?

If so, that is such a cool idea.


Lbxpdx is offline  
Reply
Old 04-08-21 | 02:41 PM
  #2  
randyjawa's Avatar
Senior Member
Titanium Club Membership
15 Anniversary
 
Joined: Apr 2007
Posts: 12,565
Likes: 2,739
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).
__________________
"98% of the bikes I buy are projects".
randyjawa is offline  
Reply
Old 04-08-21 | 02:47 PM
  #3  
degan's Avatar
Senior Member
15 Anniversary
 
Joined: Nov 2010
Posts: 941
Likes: 146
From: Oregon
For draining water? How could enough water get in there to necessitate a drain plug? +1 on the grease port idea, just not the standard location.
degan is offline  
Reply
Old 04-08-21 | 02:53 PM
  #4  
non-fixie's Avatar
Cyclotouriste
Titanium Club Membership
15 Anniversary
 
Joined: Aug 2009
Posts: 11,785
Likes: 6,996
From: South Holland, NL

Bikes: Yes, please.

Looks more like an attachment braze-on of sorts to me. Rear fender? Generator?
__________________
Shuffling with the prince












non-fixie is offline  
Reply
Old 04-08-21 | 03:05 PM
  #5  
gugie's Avatar
Bike Butcher of Portland
Titanium Club Membership
10 Anniversary
 
Joined: Jul 2014
Posts: 12,444
Likes: 7,978
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?
__________________
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.
gugie is offline  
Reply
Old 04-08-21 | 04:34 PM
  #6  
Senior Member
5 Anniversary
 
Joined: Jun 2019
Posts: 583
Likes: 184
Is there a mount high up on the back of the seat tube for a lever to activate a generator?
AeroGut is offline  
Reply
Old 04-08-21 | 05:04 PM
  #7  
framebuilder
Titanium Club Membership
15 Anniversary
 
Joined: Dec 2009
Posts: 1,788
Likes: 2,707
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.
Doug Fattic is offline  
Reply
Old 04-08-21 | 05:19 PM
  #8  
Senior Member
5 Anniversary
 
Joined: Jun 2019
Posts: 583
Likes: 184
Typically there is a lever on the back of the seat tube that looks like a shift lever and it pulls the generator into contact with the tire via a shift cable. I’ve seen them most often on Japanese touring bikes
AeroGut is offline  
Reply
Old 04-08-21 | 05:26 PM
  #9  
Thread Starter
Full Member
5 Anniversary
 
Joined: Oct 2020
Posts: 421
Likes: 331
From: Portland
This is a 1991 Trek 990 by the way.
Lbxpdx is offline  
Reply
Old 04-08-21 | 05:29 PM
  #10  
iab's Avatar
iab
Senior Member
Sheldon Brown Memorial - Registered
15 Anniversary
 
Joined: Jun 2006
Posts: 12,859
Likes: 5,389
From: NW Burbs, Chicago
Originally Posted by gugie
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.
An oil drain hole was standard equipment on the Cinelli SC from 1951 to about 1965. Not to say I think the OP ting is an oil drain hole, I don't. Bad location.

iab is offline  
Reply
Old 04-08-21 | 05:35 PM
  #11  
Señor Member
Titanium Club Membership
15 Anniversary
 
Joined: Dec 2007
Posts: 961
Likes: 444
From: Colorado
Originally Posted by Lbxpdx
This is a 1991 Trek 990 by the way.
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.

Last edited by CO_Hoya; 04-08-21 at 05:38 PM.
CO_Hoya is offline  
Reply
Old 04-08-21 | 06:18 PM
  #12  
Reynolds's Avatar
Passista
Titanium Club Membership
20 Anniversary
 
Joined: Jul 2005
Posts: 8,247
Likes: 1,211

Bikes: 1998 Pinarello Asolo, 1992 KHS Montaña pro, 1980 Raleigh DL-1, IGH Hybrid, IGH Utility

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.
Reynolds is offline  
Reply
Old 04-08-21 | 06:27 PM
  #13  
Erzulis Boat's Avatar
Senior Member
20 Anniversary
 
Joined: Oct 2005
Posts: 1,885
Likes: 843
From: Santa Barbara Calif.
Originally Posted by CO_Hoya
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.
Haha! Love this forum section. I'll be damned......................
Erzulis Boat is offline  
Reply
Old 04-08-21 | 11:04 PM
  #14  
cyccommute's Avatar
Mad bike riding scientist
Titanium Club Membership
20 Anniversary
Community Builder
Community Influencer
 
Joined: Nov 2004
Posts: 29,141
Likes: 6,201
From: Denver, CO

Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones

Originally Posted by CO_Hoya
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.
Yup. In the early 90s, mountain bike builders realized that running the cable along the top tube is cleaner but top pull derailers hadn’t been developed yet. There were a number of pulley systems around that era but Trek’s approach was unique.
__________________
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!





cyccommute is online now  
Reply
Old 04-09-21 | 03:51 AM
  #15  
Senior Member
Titanium Club Membership
5 Anniversary
Community Builder
 
Joined: Feb 2020
Posts: 4,001
Likes: 2,317
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.
oneclick is offline  
Reply
Old 04-09-21 | 11:27 AM
  #16  
Velo Mule's Avatar
Senior Member
5 Anniversary
 
Joined: Dec 2016
Posts: 2,937
Likes: 1,797
From: Long Island, NY

Bikes: Trek 800 x 2, Schwinn Heavy Duti, Schwinn Traveler, Schwinn Le Tour Luxe, Schwinn Continental, Cannondale M400 and Lambert, Schwinn Super Sport

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.
Velo Mule is offline  
Reply
Old 04-09-21 | 01:03 PM
  #17  
gugie's Avatar
Bike Butcher of Portland
Titanium Club Membership
10 Anniversary
 
Joined: Jul 2014
Posts: 12,444
Likes: 7,978
From: Portland, OR

Bikes: It's complicated.

Originally Posted by oneclick
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.
Which is why you don't see builds done this way anymore, excellent analysis however.
__________________
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.
gugie is offline  
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.