All the various parts of the rack even the aftermarket rack are impacted by the weight. 150lbs is lots of weight for 4 small points of contact to hold. These giant roof boxes crack me up given large bulky light stuff works but smaller heavier items easily can be packed in these huge boxes and easily push the weight limit of the feet that hold each end of the bar in place.
I've run just a hair over 150lbs during a Triatholon trip. On Yakima bars and feet clipped to real rain gutters. Very bad storm and highway speeds we actually had the rear feet come loose. What happens is that the bar bends and stresses the feet and that is where your failure happens. For the stock bars 150lbs is for sure as far as I would go especially with lots of road miles involved. Every fuel up I would also suggest you do a very close inspection to all the fittings and brackets stock rack or otherwise. Wind - vibration etc can loosen up the fittings so checking them and remounting them or snugging them up isn't uncommon during long trips.
Make sure you have a allen wrench that fits the stock bar screw that holds the fixed side of the cross bar in place. Chances are you will never ever need to mess with it but the one time you find it working loose you will wish you had a random allen wrench laying in the bottom of the glove box.
I've run just a hair over 150lbs during a Triatholon trip. On Yakima bars and feet clipped to real rain gutters. Very bad storm and highway speeds we actually had the rear feet come loose. What happens is that the bar bends and stresses the feet and that is where your failure happens. For the stock bars 150lbs is for sure as far as I would go especially with lots of road miles involved. Every fuel up I would also suggest you do a very close inspection to all the fittings and brackets stock rack or otherwise. Wind - vibration etc can loosen up the fittings so checking them and remounting them or snugging them up isn't uncommon during long trips.
Make sure you have a allen wrench that fits the stock bar screw that holds the fixed side of the cross bar in place. Chances are you will never ever need to mess with it but the one time you find it working loose you will wish you had a random allen wrench laying in the bottom of the glove box.