Rebrazing the Downtube to BB
#26
Senior Member
I'm just trying to figure out if the failure was from fatigue or from a more violent impact overcoming the ultimate-strength of the material in that area. Very unusual. Most of the failures I've seen were in the tubing only where it meets the lug. To much lesser degree, I've seen lugs crack just beyond where the tubing ended. But to crack through both, that's very strange...
#27
Just keep pedalling!
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Bikes: 1987 Schwinn Circuit, 1987 Panasonic DX-4000, 1984 Peugeot PSV10, 1989 Centurion Prestige, 1973 Raleigh Sprite, 1987 Peugeot Canyon Express, ~1986 Raleigh Capri, 1994 Trek 850, 1984 Centurion Pro Tour 15, 2012 Gravity Zilla
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No need for pics, I can see the crack clearly in your 1st photo. Interesting that it cracked through both the tubing and lug. Do the two borken ends fit together cleanly like a jagged jigsaw puzzle?
I'm just trying to figure out if the failure was from fatigue or from a more violent impact overcoming the ultimate-strength of the material in that area. Very unusual. Most of the failures I've seen were in the tubing only where it meets the lug. To much lesser degree, I've seen lugs crack just beyond where the tubing ended. But to crack through both, that's very strange...
I'm just trying to figure out if the failure was from fatigue or from a more violent impact overcoming the ultimate-strength of the material in that area. Very unusual. Most of the failures I've seen were in the tubing only where it meets the lug. To much lesser degree, I've seen lugs crack just beyond where the tubing ended. But to crack through both, that's very strange...