So after seeing this video from Ronny Dahl:
https://www.youtube.com/watch?v=r32xd9z4SZ4&feature=youtu.be
I'm back to wondering about a 4runners actual roof load rating. The only thing in the 5th gen manual says is "do not exceed 120 lbs cargo weight on the roof luggage carrier" which seems to me to speak to the limits of the OEM cross bars. It doesn't even mention roof load limits in the 4th gen manual. There doesn't seem to be any differentiation between the standard OEM rack and the TRD Pro rack, which must weigh more. If the roof load limit is only 120 lbs, there should be a note that the pro rack can only hold 115 lbs (or whatever the weight difference is), but there isn't.
I've been digging through posts and found one thread where somebody contacted Toyota to ask, and was basically told "modifying your car is bad, the roof rack rating is 120 lbs," lots of references to 300 lbs dynamic / 600 lbs static but no reference for where those numbers came from. Another common one I've seen is 150. Again no idea where it came from.
Rhino Rack has 220 lbs as a roof allowance for 4runners. I haven't found any other mfg say anything aside from "our rack holds XXX lbs, don't exceed your mfg rating though." If they even have that.
I've also found posts that say the roof load limit is the weight of the car, since it is designed to not collapse during a roll over. But where the rack ties in may not be the same structure as the "roll bar," although it should be.
Sooo, what is the MFG rating? Are we really supposed to stick with 120 lbs? By the time you add a full size rack, you'll be down to 30 or 40 lb capacity. It seems ridiculous that this isn't a published number. I guess that goes along with the unknown fording depth. The problem with making something so conservative, is that everyone will ignore it because it is clearly overly conservative, but now the actual limit is unknown.