I've had these kayak racks for about 4 years, so no, they are not manufacturer (which I think is Thule). I had them on a '14 Outback until last month.
I looked up the big-name brands at the time and was blown away by the price for a basic rack - not any of those with an elevator system or anything - $100+ was insane, I thought. The way I looked at it was a kayak rack is actually very simple construction. Bent steel with some foam and a mounting bracket system. So I looked on Amazon and found a pair for something like $25 shipped.
The shape that the camps are molded to doesn't fit the exact shape of the crossbar, but this does not hinder them from being safely tightened. When cranked tight, it has no slippage whatsoever. And I test with a few tugs every time I use them. Great price, great purchase, would recommend 100%.
This is the exact same product I purchased. Note the price was about $25 at the time, and has gone up. You might be able to find cheaper, or even a double set for around this same price. All the top Amazon products in the category all look to be the exact same thing.
https://www.amazon.com/TMS-J-Bar-Carrier-Mounted-Crossbar/dp/B003V57NUQ
I don't use a folding J-style rack but I do use J-style racks for my kayaks (2 of them) and they barely fit on the X cross bars. They attach nice and snug.
As for securing the kayaks down, I use the quick straps that came with my racks and make sure to tie them off to prevent slippage.
The farthest I've traveled with this setup is about an hour of highway driving (75 mph).
Edit: The racks I have: https://www.amazon.com/gp/aw/d/B003V57NUQ/ref=sxl1?ie=UTF8&qid=1467757196&sr=1&pi=AC_SX236_SY340_FMwebp_QL65
Sure thing! This is what I’ve gotten so far. My next purchase will probably be a light bar. I’ll also make a post once I have everything I linked below installed on my car.
FYI, I signed up for an Amazon credit card which knocked off $150 off my Amazon order.
Crossbars
BrightLines Aero Cross Bars Roof Racks Luggage Rack Compatible with 2014-2021 Jeep Cherokee https://www.amazon.com/dp/B07BL2L3RM/ref=cm_sw_r_cp_api_glt_fabc_PNDHNE1T197NW87JGC9A
Roof rack cargo carrier
ECOTRIC 64" Universal Black Roof Rack Cargo Carrier Car Top Luggage Holder with Extension Carrier Basket SUV Storage for Travel https://www.amazon.com/dp/B07WWGGYMG/ref=cm_sw_r_cp_api_glt_fabc_PC06BERJJACZADJFA8SH?_encoding=UTF8&psc=1
Cargo net
EZYKOO Cargo Nets 47" x 36",6mm Premium Bungee Cord Net,3" x 3" Grid Mesh Cargo Net,Auto Roof Tie-Down Net with 14 Hooks https://www.amazon.com/dp/B01L1P1ONO/ref=cm_sw_r_cp_api_glt_fabc_F3VMZSJ45RMSWKKJHF40?_encoding=UTF8&psc=1
J rack for kayaks
TMS J-Bar Rack HD Kayak Carrier Canoe Boat Surf Ski Roof Top Mounted on Car SUV Crossbar https://www.amazon.com/dp/B003V57NUQ/ref=cm_sw_r_cp_api_glt_fabc_E3ZE95A9Z6FT4EAF96A0?_encoding=UTF8&psc=1
2in lift
https://www.roughcountry.com/jeep-suspension-lift-kit-60400.html
I do have one main question in which it's been a bit hard to track an answer for: I'm mounting two kayaks (Future Beach Fusion 10 and Perception Pescador 12) on my car (Kia Forte), and am wondering the best way to go about it on the cheap.
I have a roof rack, like a luggage rack, just two bars that latch to the top of the roof. I've seen this one amazon but would like to do something like that after I get out a few times.
I've read that the cheapest way might be to go with a styofroam pad of some sort and then strap them down that way. Or, I've seen some people just stand them up on the edge side by side and strap them to the roof rack and then tie off lines on the front and back...which would be nice cause then I'd only have to but the straps and guide lines.
Anyway, any help in this would be appreciated. And if there are any guides you recommend online for strapping down a kayak that you could point to, that would be super helpful as well, as I did do a search earlier and read through about five posts, but they seemed cursory and insubstantial.