I had a custom TI road bike built 11 years ago, with sliding dropouts for a Rohloff. A few weeks ago -- after about 66,000 miles -- the left seatstay completely cracked in 2 while I was riding, for no apparent reason. (Didn't crash, hit a pothole, etc.) Sent it to get looked at, the guy said he can repair it, but it needs to be "reinforced" due to the torque of the Rohloff. (Have no idea exactly how he "reinforces" it.) Does this mean I was supposed to use the torque arm? Is that why the frame broke? I thought it was only for "regular" frames (with traditional dropouts)? I have a single-speed hardtail MTB, with sliding dropouts, also with a Rohloff. Should I get a T.A. for that, to prevent another "failure?"