Gets the kids interested in recycling and bicycling at the same time..,
of course ... and that's a work of both kids.
Now back to problems! as known this TREK has a very odd design for the front derailleur.
I thought, I could screw such a stopper clamp on the seat tube and use a top pull derailleur.
But where do I get it in 34.9 mm diameter?
Hi, I had the same problem with my '91 TREK 970, but don't worry, with a bit of effort its' very easy to solve.
So, you know the bolt, which holds the brake pad in canti brakes, right? It's drilled through in the middle so the pad can be inserted in its BIG hole. I had plenty around from previuos builds, but it's easy to get anyway. I've taken this bolt, cut off the threaded section of it, drilled a small diameter (1,5 mm) hole right into the middle of the Allen key-like head on the end of the bolt, making way for the cable wire. The wire cable outer sometimes is too big to fit into the original Allen-key hollow, so you can drill into it carefully to turn it into a wider diameter.
Then made a clamp from simple drilled steel strip which is often used for fixing and placing water spouts and easy to get from hardware/DIY shops. It's easy to bend with hand, strong enough, made in different sizes and its side pattern reminds me of a bike chain. You can use other sorts of strips, of course. When the steel strip was measured and cut to fit the frame tube, then placed "the cable holder-bit" vertically tightly next to the seatube, wrapped the drilled section of the steel strip around the frame and with a bit of luck the BIG hole of the bolt & strip holes get even.
Now comes the trickiest bit. I took a 6 mm Allen bolt, inserted into the BIG hole of the original brake bolt, and carefully marked it with a pen right through the SMALL hole previously made for the wire. This is essential in order to be able to fix the whole "full stop clamp" with only one bolt on the frame. The cable wire runs through this bolt, so accurate measurement is vital! Then drilled through with the same diameter (1, 5 mm should be enough for the wire) as was used on the brake bolt.
Now I've could insert a bolt into them to make the whole "thing" to work as it should, looking not too fussy, fixed with only one bolt, and without welding! I'm going to include pictures, cause my description can be chaotic I know, English is only my second language
circa '87-88 Kettler ALU-RAD,'89 Dawes Escape,'91 TREK 970 modded, '91 TREK 8000, '91 GT Zaskar, unknown model Pinarello alu DX/XT, '92 Marin Rocky Ridge, '90s WILLIER MTB,'95 KTM Race-Line