Put a steel worm screw band on the headtube, much stronger than any tape would be. As to the down tube crack: use a sharp
pointed center punch to dimple each end of the crack and drill ~3/32" hole there. This will reduce the risk of propagation of the
crack. FWIW back in the '70s I crimped a downtube at the shifter bosses (ran into curb) eventually it broke, got welded and
ridden for a time. About 15-18 miles from home the down tube split in half a year or so later. Had to ride it to get home so used
some 14g copper wire to bind the top tube and down tube together, kind of bouncy but I was able to get home. No injury, no crash
just a WTF and then a search for wire or something.
I think it is ok to use on a trainer, especially if the fork really is steel, especially the Kurt kind where the front wheel just sits on
the floor and the rear is clamped in place. Just don't do any 1200 watt standing sprints or maybe even 800watt.
Last edited by sch; 08-05-20 at 11:23 AM.