Roller-assist roof devices and J-bar racks

Has anyone ever used a roller-assist device such as
https://amazon.com/Seattle-Sports-Sherpak-Suction-Mounting/dp/B07QHX5GRF
with a J-bar rack that holds a kayak on its side suchs as
https://amazon.com/dp/B00FUHDYZQ?aaxitk=Ax42E8R0zEAqFLgUfbKTKg

Obviously the kayak would have to be rotated almost 90 degrees before attempting to slide it up the roller and onto the tack. I’m wondering if it would work or just slide off.

I’ve been using a mat to protect the back of my Venza mid-sized cross-over and slide it up that but the 'yak doesn’t slide well on the mat at all so I’m trying to decide whether to try a roller assist device or bite the bullet and buy a cradle rack with built-in rollers.

-l2t

I would worry about it slipping sideways unless the J cradles are mounted directly in line with the roller.
Suggestion: if you have cross bars; why not buy a set of saddles without rollers, ( Much cheaper) and then mount them in line with that roller device.
I slide kayaks on plain saddles all the time . I have several sets, and on one have even glued pieces of carpet so the yaks slide easier

I agree with Jack. I tried rollers but like saddles much better.

Forget J-bars. Use some type of saddle. Many kinds out there. I made my own roller out of PVC and wood dowels. With suction cup dent puller. BUT now use a Thule Slip-Stream .

I have long used the Amagansett Roller Loader. Like since about 2002. You have to be attentive to the angle of the hull as the boat goes up and down, but l have found it to be decent thru small Subs with unfortunately increasing roof heights and spoilers.

Later add - I have never used Jbars because of needing to be able to load solo. Didn’t with my husband either. We used old fashioned stackers, and after he passed away I went to glide pads and saddle for the second boat side opposite the Hullivators I finally got for my primary boat. Bottom line is, anything that means you can’t put the boat up initially flat on its hull it a PITA for solo loading.

I use the Sherpak rollers with Thule Dockglide Kayak Saddles (positioned in the center of my crossbars) to load my 56 lb. Greenlander Pro on to my '14 Honda CRV. The roller works well to get my boat to the back saddles, then I slide it on the back saddles to get the boat positioned to be tied down. The rubber surface of the front saddles grip the boat and keep it in place. At age 69, I find it easy to load/unload my boat.
I do not recommend the Sherpak for use with J-racks as it would not work well for loading a boat on it’s side. I have J-racks on the driver side of my crossbars and can load my boat on to them using a step stool but it isn’t nearly as easy as using the Sherpak/Dockglides. About the only time I use the J-racks is when someone else is there to help load/unload the kayak.

You can keep the J cradles and use a roller system of your choice to slide the kayak up over the rear of your car. Have the J cradles mounted as far outboard as possible but rotate the J cradles 180 degrees so the high side is outboard. Doing this gives most of the rack width so the kayak does not slide off the racks/roof. Slide or roller the kayak on the roof then flip the kayak on its side into the J cradles. This is a common practice where I live for solo loading/unloading of heavy plastic SOTs and fishing kayaks. I observed a rather petite women load an SOT on top of her Jeep Wrangler with relative easy; kind of surprised me.

@semdoug said:
You can keep the J cradles and use a roller system of your choice to slide the kayak up over the rear of your car. Have the J cradles mounted as far outboard as possible but rotate the J cradles 180 degrees so the high side is outboard. Doing this gives most of the rack width so the kayak does not slide off the racks/roof. Slide or roller the kayak on the roof then flip the kayak on its side into the J cradles. This is a common practice where I live for solo loading/unloading of heavy plastic SOTs and fishing kayaks. I observed a rather petite women load an SOT on top of her Jeep Wrangler with relative easy; kind of surprised me.

That’s a good idea just make sure your rack pads are in good shape.