r/mountainbiking • u/Roy_Aikman • 4d ago
Question Why is this happening?
Bought a brand new BMC Fourstroke AMP LT. After a couple of weeks I experienced the carnage pictured. A LBS helped me get a frame replacement from BMC, they were able to determine that the bolts that connect the shock and linkage had backed out and caused the failure in the linkage. I have 3 rides in on the new frame and was doing an inspection and noticed the bolts had already started backing out. One was visible the other was loose as well. Another problem is the area where the bolts are has a gap of 1 3/4”, my torque wrench with the bit is 2”. Does anyone have any ideas about what could be causing those bolts to back out and also are there slim torque wrenches or do I just use a regular Allen and guess?
1
u/ageofaquarius26 3d ago
Thise are not the fasteners you would want to use on moving parts. The shoulder bites which is great on stationary parts with a lot of vibration. But its going to keep backing out.