different types of boss kits?

[CAP57]

I found a doner frame and took out the boss kit on the frame however it looks like one side of this boss kit has some extra bumps where my frame only has a single hole for the screw that joins the 2 sides together. The other side fits on the frame nicely. Can I just shave this little node off with a dremel? It looks like it might be metal with some rubber around it. Is there a specific replacement part I should be looking for? is there a specific type of housing stop that is compatible with these? most of the ones I am seeing show a concaved edge while the boss kit is flat.

 

[black lightning 1987]

The idea of the small diameter pin is to keep the boss from trying to rotate without relying on the concave profile to do that function. It would be more important for down tube shifters than STI but I would prefer to drill a hole in the down tube for it if it were my bike. On the CAAD2 frame I have here, the small hole is about 4 mm in diameter and it's located about 9 mm on center from the central hole, in line with the center line of the down tube and on the bottom bracket side of the central hole. Older frames could be different. I might be able to check one given some time.

I would think that your frame had the hole originally. Wondering if it could have been filled in before the repaint.

 

[CAP57]

The idea of the small diameter pin is to keep the boss from trying to rotate without relying on the concave profile to do that function. It would be more important for down tube shifters than STI but I would prefer to drill a hole in the down tube for it if it were my bike. On the CAAD2 frame I have here, the small hole is about 4 mm in diameter and it's located about 9 mm on center from the central hole, in line with the center line of the down tube and on the bottom bracket side of the central hole. Older frames could be different. I might be able to check one given some time.

I would think that your frame had the hole originally. Wondering if it could have been filled in before the repaint.

My friend said this frame was a prototype so maybe thats why there is no serial and some of the holes seem different from other similar frames. I don't feel too comfortable drilling into the actual frame but I would be ok to try that on the small parts. The hole in the bottom of the seat stay is roughly 1/8" in diameter. Would I be able to just put a 1/8" pop rivet into that hole? I would need to drill a 1/8" hole into the cable stop? That might be too large for the small piece.

 

[black lightning 1987]

Bottom of seat stay or chain stay? A single rivet in the center of the stop from the donor bike might be enough. You would have to drill a hole in the stop. Before doing so, be sure that the nose of the rivet tool will fit in there.

If properly located it shouldn't be too hard to drill a hole for the shifter bosses. Measure well and mark the location with a very sharp and very lightly struck center punch. You don't want to dent the tube. Start with something like a 1/16" bit.

 

[CAP57]

Bottom of seat stay or chain stay? A single rivet in the center of the stop from the donor bike might be enough. You would have to drill a hole in the stop. Before doing so, be sure that the nose of the rivet tool will fit in there.

If properly located it shouldn't be too hard to drill a hole for the shifter bosses. Measure well and mark the location with a very sharp and very lightly struck center punch. You don't want to dent the tube. Start with something like a 1/16" bit.

Sorry I meant chain stay. I am going to try and use the boss kit with a shaved off head for now and see how well that stays in place. Do you suggest putting washers or anything between the frame and boss?

 

[black lightning 1987]

I have never seen anything placed between the boss and the frame tube. Anything soft would just make it more likely to rotate under load.

 

[CAP57]

new problem today with this build. I was able to attach the boss kit but I am finding that the bolt which connects the two heads together is a little bit too long and will need to be trimmed down by about 4mm in order for me to properly fit on the downtube adapter screws. Are there different lengths available for these downtube boss kits? Should I cut into the bolt or would it be a better option to cut the screw which attaches the adapters to the boss kit?

 

[black lightning 1987]

Down tube diameters varied through the years so it's likely there were different lengths of the threaded rod. I would just cut what's not needed off with a hacksaw, then touch the threads up on a bench grinder. If you keep the grinding wheel spinning toward the cut off end, with the rod at a shallow angle, you can clean out any burrs and round off the cut end. Be sure to cut the end that has extra threads.

 

[CAP57]

Down tube diameters varied through the years so it's likely there were different lengths of the threaded rod. I would just cut what's not needed off with a hacksaw, then touch the threads up on a bench grinder. If you keep the grinding wheel spinning toward the cut off end, with the rod at a shallow angle, you can clean out any burrs and round off the cut end. Be sure to cut the end that has extra threads.

thanks. any thoughts on just adding a washer to take up the extra spacing? the downtube adapter seems pretty secure in there and should not see much movement since i am not running downtube shifters.

 

[black lightning 1987]

I don't think adding a washer under the nut would work, at least with a Shimano cable adjuster. I measure the depth of the recess on the back side of the adjuster at .48", almost exactly the same as the height of the nut.

 

[CAP57]

I don't think adding a washer under the nut would work, at least with a Shimano cable adjuster. I measure the depth of the recess on the back side of the adjuster at .48", almost exactly the same as the height of the nut.

I was able to use a small spacer and fill in the gap. It seems pretty secure for now. The bike is up and running now. Just waiting for the weather to clear up to do some test rides and then hand it off to the original owner. Thanks again for all your help!

 

[black lightning 1987]

Glad to hear you got it operational.