Anybody successfully fixed the infamous broken Trek aluminum downtube bosses?
08-09-16, 04:48 PM
#1
Cyclist
Thread Starter
Anybody successfully fixed the infamous broken Trek aluminum downtube bosses?
Picked up an old trek 1420 aluminum frame to hang parts bin stuff off and flip, and, even though i inspected it at the time of purchase (I'm familiar with this issue), the right downtube boss just broke off on the first test ride. anybody have a very cheap solution? I'd be very surprised if jb weld could stand up to the stresses. I have no attachment to the bike so I'd rather just get another (steel) frame instead of putting any money into repairing this one. Nothing more frustrating than getting the bike totally tuned up and have this happen. 
08-09-16, 07:14 PM
#2
Senior Member
Join Date: Dec 2014
Location: Central Virginia
Posts: 4,777
Bikes: Numerous
Mentioned: 150 Post(s)
Tagged: 0 Thread(s)
Quoted: 1676 Post(s)
Liked 3,084 Times
in
911 Posts
I'm not familiar with the issue specific to Treks. Is it a rivnut? There are a couple of different strategies for dealing with those.
08-09-16, 07:49 PM
#3
Senior Member
Join Date: Feb 2014
Location: Southern Ontario
Posts: 1,883
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 263 Post(s)
Likes: 0
Liked 9 Times
in
8 Posts
This was recommended in another thread.
NOVA LEVER BOSS KIT FOR AL FRAME :: SMALL PARTS :: BRAZON/SMALL PARTS :: Nova Cycles Supply Inc.
https://www.bikeforums.net/bicycle-me...cs-inside.html
NOVA LEVER BOSS KIT FOR AL FRAME :: SMALL PARTS :: BRAZON/SMALL PARTS :: Nova Cycles Supply Inc.
https://www.bikeforums.net/bicycle-me...cs-inside.html
08-09-16, 10:20 PM
#5
Senior Member
Join Date: May 2011
Location: Upstate NY
Posts: 3,783
Bikes: Bianchi San Mateo and a few others
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 634 Post(s)
Likes: 0
Liked 13 Times
in
9 Posts
If you're going to reattach that boss or another one in its place, you're going to need a good epoxy. Skip the consumer-grade stuff like JB-Weld. West System, Aeropoxy, and others all make stuff that should do the job if anything can ...but the good stuff isn't cheap. 3M DP-460, mentioned on the Nova web site Slash5 posted above, might be the best bang for the buck. Its 4,000 PSI shear strength is about four times what JB-Weld's supposedly is, and you can get a one-ounce tube of it from Amazon for around twenty bucks.
Another option would be to ditch the downtube shifters. If you've got some barcons in your parts bin, you just need to rig up downtube cable stops and you're good to go. You could use a boss-mounted stop on one side and a single cable clamp-on stop for the other. Or a two-cable clamp-on and leave the remaining boss naked.
Another option would be to ditch the downtube shifters. If you've got some barcons in your parts bin, you just need to rig up downtube cable stops and you're good to go. You could use a boss-mounted stop on one side and a single cable clamp-on stop for the other. Or a two-cable clamp-on and leave the remaining boss naked.
Last edited by SkyDog75; 08-09-16 at 10:24 PM.
08-09-16, 10:48 PM
#6
Full Member
Join Date: Feb 2013
Location: Worcester, Massachusetts
Posts: 308
Bikes: Fuji Sportif 1.7C, Shogun Metro AT, Jamis Durango SX, Miyata Alumicross, Fuji Special Road Racer, Mongoose ATB, Fuji SST 1.0 Team, Gitane (?), Specialized Rockhopper SS, Univega Gran Turismo, Univega Supra Sport Mixte, Nishiki Tri-A, Diamondback Coil
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Liked 141 Times
in
78 Posts
I'm approaching a year on a J-B weld fix on my 1100. I definitely try to take it easy on the affected boss (FD) but it's holding up fine. Surface prep, time, and a good clamp are key. It will probably be noticeable anyway, but I have to say I would be up front and disclose the repair. Great bikes though, I've had a few. Light and tough. Except for those bosses lol.
