Goplus 2 Pairs Kayak Roof Rack, Universal Kayak Carrier J-Bar Rack with 4 Tie Down Straps, Canoe Boat SUP Surfboard Ski Board Rooftop Mount Rack on Car SUV and Truck Crossbar

Here’s the deal on these J carriers.They are on the cheap side but if you’re handy and know what you’re doing they work great. They work great for my purposes on a kayak trailer frame I built.Each J comes in two pieces with a top and bottom plate to mount onto the frame/cargo bars. There are four bolts with locking nuts that secure the two J pieces together through the top plate. The bottom plate uses a longer bolt with the hand tightening nut. See picture.When I first put them on, they were solid. I load the kayaks a couple of days later for the first time. and then both the J frame itself is loose and the top plate locking nuts are loose on 5 out of the 8 J bars.I was 8 hours from leaving and very upset that these things wouldn’t work.What was disappointing up to this point is that the bolts are all Phillips screwdriver bolts and not traditional hex head bolts. This made tightening difficult but I thought I had cranked on them sufficiently. Apparently not.However, I figured what the problem with the design is (aside from the screwdriver head bolts).There is a rubber protector that goes around the entire base of the J bar to protect the kayak from the bolts. This rubber apparently had not been compressed enough by the time I loaded the kayaks and the bolts were now loose because the rubber stretched or got squished out between the top plate.I re-tightened the nuts again and appeared to have re-solidified them to my frame.We traveled 500 miles on them bouncing on a Harbor Freight trailer and they haven’t budged.So when you read the reviews that say they come loose, believe it. You’ll just need to pay attention to them and keep cranking on them to get them solid.I plan to replace the screwdriver head bolts with actual bolts to ensure I get a solid tightening before taking the next trip.For the money, I am happy for the purposes I am using them for.If I was putting them on a roof-top of a car and wasn’t handy, I think I would spend the money on a higher quality set. However, a savvy user could make them work well.

Since crossbar of utility trailer is more thick than roof rack crossbar, I purchased longer bolts. It is great set for two kayaks!