The Flux RK is the continuation of the RK30 and it’s their softer more park oriented binding. It’s got a pretty soft Urethane high back but it’s not going to be noodle soft like some bindings with urethane in it.
Flex: The flex is very soft but more responsive than you would think. You can bend this high back all the way back perpendicular to normal with ease. It also twists increadibly easy and is super playful. There is a lot of freedom of movement if you have boots without a spine.
Adjustability: Like almost all Flux bindings it has great adjustability and it can be tweaked out almost any way you want it.
Comfort: Very comfortable as well as being supportive. You can crank the straps down and there are little to no pressure points.
Heel-Toe Response: The new base plate gives a little more edge to edge response making this borderline good. If you like a more mellow binding but have a moderate turning board this can work. It’s best with softer easier turning park twins but you can get all mountain freestyle with this.
Tip-Tail Response: This year the new base plate has a little less contact due to the rounded sides but everything underneath is still in direct contact with the board. It butters and presses pretty well thanks to the supportive ankle strap and does a pretty good job getting the board to flex.
Boot Support: Very good support for a park oriented binding and it really wraps around the ankle giving your boot a solid feel in there.
Ratchet System: Same great ratchet system that all the Flux bindings have. It’s smooth and catch free. One of the better ratchet systems in the league.
Shock Absorption: Not quite there. We’d like to see more of the heel removed and replaced with EVA. It’s probably the only real weakness. However if you like a more skate like feel you will enjoy this.