The Flux GU is the evolution of the GU15 and despite the minor name change the ride is very similar. From what I understand is they took out the #’s after the letters in the name because each one has a different flex according to size this year. So in other words the carbon/nylon blend is slightly different for each size.
Flex: With the Urethane in the high back you would think it’s super noodle but it’s actually a nice blend of urethane and nylon so it’s not like some of the super soft urethane bindings out there. It’s got decent support but still has a good amount of tweakability.
Adjustability: Flux bindings are all about adjustabilty. The Flux GU is completely tooless on the top. You only need a tool for the disc. The Heel can be adjusted like the toe ramp and this isn’t a bad feature but if they could add more shock absorption we’d gladly sacrifice the heel adjustablitiy. Still this is a very easy to adjust binding that many will be very happy with.
Comfort: Very comfortable. The ankle and toe strap wrap well and generally don’t cause pressure points and fit around your toe and ankle well.
Heel-Toe Response: Much more edge to edge response than you would think. It’s high back is firmer than most urethane high backs so it offers a little more on the heel side and the toe side seems to have pretty good drive as well for their softer bindng.
Tip-Tail Response: Most bindings these day have a reduced dead spot that allows the board to flex pretty easy under foot. This still has a lot of contact with the board but the sides are rounded up and there is some urethane in the edges of the heel which makes the board bend a little easier than the older base plates. Combined with the supportive ankle straps the bindings can bend most freestyle boards well but they still aren’t competing with the bindings that have more of a reduced dead spot.
Boot Support: Great support and even though it doesn’t have the larger asymmetrical ankle strap it locks in the boot pretty well and there is some firm support going on.
Ratchet System: Top notch ratchet system that we have no complaints with. It’s very smooth and cranks well. It also releases well too.
Shock Absorption: The urethane dampeners help a bit but you still have a pretty hard heel for flat landings. We’d like to see them expand on this Urethane idea and make it more prevalent in the heel cup.