Giant Cadex CFR3 seat clamp fail

garabet

While trying to (over) tighten the integrated seat-clamp of my Giant Cadex CFR3 (circa '92-94), my girlfriend managed to crack the clamp/lug (see image below).
Though the main tubes are carbon, the lug in question is made up of aluminum.
The seat tube does not extend above the top tube, so there's no possibility to use another seat clamp to hold the post in. I showed the bike to my LBS asking if the lug could be welded but he replied in negation because of the material (Alu) and the fact the heat from welding might impact the integrity of the carbon tubes and/or their attachment to the lugs.

So any of you bike gurus has a workaround to the problem at hand without compromising safety much? or is the frame simply unusable anymore?

all feedback is much appreciated.
G

dgunthor

a thick washer to press on the broken part may sort it, so the bolt tightens the washer and holds it all together

(may need to do some fettling obviously)

topdude

Put seatpost back in at the correct height and aligned with top tube.
Drill right through lug and post.
Fit suitable nut and bolt.
Could be done quite neatly if suitable bolt used.

dgunthor

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19662367#p19662367]topdude[/url] wrote:

Put seatpost back in at the correct height and aligned with top tube.
Drill right through lug and post.
Fit suitable nut and bolt.
Could be done quite neatly if suitable bolt used.

that's a better idea

garabet

great. thanks. that seems to be a feasible one.
I'm thinking of shimming the seat post with an extra adapter before drilling, to keep it from moving around in the tube so as no to put extra force on the bolt leading to a snap at an undesired moment. But in theory it should work.

Ben6899

Regardless of the fix, the fact your good lady trashed your frame, you can do what you like for about a month!

Carpé diem.