Originally Posted by _cy_
seems on R1200GS rear caliper bolts factory spec is a super low 18ft lb .. which IMHO is a fuck up by BMW. no one else no one else in the world that I'm aware of uses 18ft lb torque that low to hold together a mission critical part like brake calipers.
I'm very careful with BMW torque specs, as I have learned the hard way. Back in 2004, I was working on a customer's brand new M3. I didn't have a manual for the car, but having done the simple task I was doing many times on many other cars, wasn't worried about it. Set the torque wrench to what I had used for the same diameter and pitch fastener in the same place doing the same job on my 1985 Toyota, and snapped the dang thing off. Had to buy a new $90 part (fastener was a pressed-in stud, not available separately) because BMW saved $0.03 on a crappy fastener. Later found a manual and saw the BMW torque spec on that fastener is less than half of the Toyota spec. On all the other cars I've worked on, the Toyota is typical. So you really have to follow the manual with German stuff.
Just to benchmark, I pulled up the manual for a K8-K9 gixxer. Its rear caliper has three different fasteners doing three different things, and these are the recommended torques:
33 N⋅m (3.3 kgf-m, 24.0 lb-ft)
18 N⋅m (1.8 kgf-m, 13.0 lb-ft)
16 N⋅m (1.6 kgf-m, 11.5 lb-ft)