mconlonx

I don't see that any of those are newer than 2-3 years ago. Could Tern have fixed the problems by now?

I also don't see any resolutions posted -- how were the complaints resolved? Frames replaced? Medical expenses covered?

I'm no expert, but I have welded aluminum and am familiar with manufacturing processes. It would not surprise me at all to learn that these were all produced in the same factory within the same time frame. And my educated guess is that they might have been using an incorrect filler rod while TIG/MTAW welding these bikes together. What we don't know and may never know is whether this was a mistake on Tern's end, where they spec'd the incorrect filler rod, or on the manufacturing end, where they either made incorrect assumptions on missing information, followed Tern instructions regarding a bad call on filler rod, or used the wrong type of filler on their end. There could also have been some kind of contamination which was not cleaned off either the filler or the tubes, an incorrect heat treatment used, or a limited number of other considerations.

Having worked in a bike shop, I have also seen failures in aluminum, steel, titanium, and carbon bikes. What is interesting on the Tern bikes is where the failure occurred -- at the weld, vs just off the weld in heat-affected tubing, which is a much more common failure mode in aluminum bikes.