Originally Posted by
dddd
Could some sort of "device" be fed up the downtube through the bottom bracket opening?
I'm imagining a piece of tubing, cut in two, about an inch long, with a cone wedge in each end.
Connected to a brake cable housing with a cable attached so as to compress the split tube from both ends, thus expanding it in the vicinity of the dent.
One could feed the device in, slide it up the downtube, apply cable tension to slightly expend the tubing until resistance is felt to sliding the device past the dent.
Once positioned, additional cable tension would wedge apart the tubing, pushing the dent flush with the inside of the tube.
The wedge cones would need a steep enough angle so as to assure their release of expansion when cable tension was released (a stiff compression spring could also be used to push the wedges apart from the split tubing).
I've had a similar sort of idea, using a shortened stem quill with the extension removed.
These have enough mechanical advantage to expand steerer tubes, so as long as you could figure out a way to get enough torque on the bolt ... Probably would be a good idea to reinforce the area with blocks to counteract force on the opposite side of the dent. One may not need that much torque, actually, since the force would be very concentrated on the dent.
Would need to be really stubby to get around the corned from the bb shell into the down tube.
But with my luck, it would get stuck in the bike after...