Originally Posted by Cyclemark

There are many posts about frame failure. For those inquiring about this, I have a frame that just failed.

I have an aluminum road bike frame that cracked above bottom bracket. It cracked almost all the way through the seat tube and the down tube. It was a stress failure as the bike was never crashed and always ridden on the road.

There was no warning except the rear derailleur kept shifting when out of the saddle. I am not a heavy rider (less that 140 lbs) so this bike would have probably failed sooner if used by a heavier rider.

Looking at the crack, it was along the tubes and the welds, so that area was not designed strong enough. The thickness of the tube wall looks less than 2 mm. If the wall thickness was butted (as it was specked) it should have been thicker near the welds.

Seems like the frame company sacrificed strength for a little weight savings.