Hello
I don´t want to be seen as a guy who (always) has frame breaking and warranty problems..
but here we go again:
In the end of May I loved riding the FM121 in the local sandy hills full of pine trees. One day I washed the dust covered bike and removed the rear wheel and saw it: just above the rear brake mount was a crack going around the seat stay.

Someone predicted in this topic last winter that FM121 has a weak spot there and I think he is right.
I contacted Tantan and sent pictures of the frame. Everything went well and got the message I get a new rear triangle.. but I have waited for it for 4 months now. They offered me a different color rear triangle after two months, but told them it has to be same.