Updates Prime X Carbon
Since we tested this binding, it has been updated with aluminum hardware to save weight, and there are dropped sidewalls, meaning the inside sidewall is lower than the outside sidewall to provide more range of motion. Notice the subtle differences in the two bindings below. The latest version is pictured first, followed by the version we tested.
We're linking to the updated version, but be aware that the following review pertains only to the previous Prime X Carbon.
Hands-On Review of the Prime X Carbon
Karakoram's Prime X Carbon represents the top of their splitboard binding line. Functioning similarly to the rest of the Karakoram bindings, the Prime X Carbon provides active joining of the two halves of a splitboard to improve performance. It's the lightest Karakoram binding and is still impressively stiff; Karakoram has tweaked their interface and improved transition speed and ease.
These bindings feature high performance on the skin track and on the downhill but are heavier and more complex than other options. If you are fan of the active joining technology or have previous experience with splitboards where you felt the riding performance was lacking, and are comfortable with somewhat more complex transitions, these bindings might be the ticket for you.
Uphill Performance
In tour mode, the Prime X Carbon connects to the touring interface using an axle that freely rotates similarly to a bike axle. The connection is secure and confidence inspiring. The Prime X Carbon also climbs and tours well.
Weight
As the lightest offering from Karakoram, the Prime X Carbon allows you to gain the summit with more energy in reserve than any other Karakoram binding. They can achieve this by use of carbon and high-quality aluminum throughout the binding. On our scale, our size medium Prime X Carbon weighed 715 grams (per binding). For perspective, this is lighter than all of the bindings from Voile we have reviewed and lighter than other Karakoram bindings. It is heavier than the Spark R&D Arc and Surge.
Transitions
The transition from riding to touring was straightforward and efficient with the Prime X Carbon. Pulling down on the release lever removes the bindings from the board easily; once the splitboard is separated, the bindings grab onto the touring interface quickly. It is a nicer feature that the bindings can be locked into touring mode simply by rotating them flat to split ski (which is where gravity wants them to be anyway).
Transitions from touring to riding can be more challenging. The new Ride Mode 2.0, what Karakoram calls their new interface, is a significant improvement over the previous design. It definitely allows for the bindings to be clamped to board with a wider range of tolerances and handles inevitable snow on the interface better. Still, compared to the Sparks or Voile bindings, we found putting the splitboard back together was difficult when snow conditions were challenging. The difference has been reduced by Ride Mode 2.0, and with practice and a solid routine it should rarely be an issue, but the system does require a touch more snow clearing and preparation than the puck based systems we reviewed.
Downhill Performance
The entire premise of the Karakoram system is that the active joining these bindings provide increases performance. It is clear that the bindings do securely clamp the two parts of the splitboard together; the Prime X Carbon's have rubber contact points near the edges of the splitboard that make contact with the board. Unlike the puck-based system used by Spark and Voile which only contact the splitboard through the pucks, the Prime X Carbon binding touches the board near the toes and heel. It makes sense that this should improve feedback and control. Truthfully, the Karakoram's do produce high-level performance. The feedback and control are excellent, yet it is also true that the best bindings from Spark also ride very well (and it is not clear that Karakoram's performance is better).
Straps, Lean, and Risers
Straps
The Karakoram straps work very well, as the ankle strap buckle is easy to operate and tightens effectively. Our toe strap features a traditional buckle that is fine, although you do need to accurately line up the ladder into the buckle. Despite our bindings being purchased Fall of 2018, they do not have the minimal toe strap design that is shown on some of the images of the Karakoram site.
Lean
We are big fans of the carbon high backs on the Prime X Carbon; the high backs are very stiff and responsive, but not painful or overly rigid. They are also damn good looking. The forward lean adjusters rotate to switch between touring and riding modes, and it's easy to operate them.
Risers
The Karakoram risers are intended to be operated using the basket end of your ski poles. In our experience, this mostly worked but does require precision, which can be a little tricky to master.
The Prime X Carbon bindings also feature a heel lock mechanism that allows the user to ski or skate without the heel of the binding coming up. This feature worked fine in our testing, but we generally do not find this feature to be necessary.
Value
The Karakoram Prime X Carbon retail for over nine hundred dollars. That is far more than the next most expensive non-Karakoram binding, the Spark Surge Pro. It is tough to make a value argument for the Prime X Carbon bindings unless you are all in on the active joining technology. If you feel this feature is necessary for your splitboard performance and you want the best and lightest binding that Karakoram makes, we'd recommend giving this one a shot.
Conclusion
The Karakoram Prime X Carbon bindings represent a significant improvement from Karakoram bindings of a few years ago. The interface is easier to use, and the bindings are relatively lightweight. They also feature a beautiful and functional carbon highback. However, there is no escaping the high cost of these bindings relative to other quality options.
