Petzl Neox Review

All assisted-braking devices (ABDs) must toe the line between providing a secure rope-pinching mechanism when the climber falls, and also allowing the belayer to feed out slack quickly when the lead climber is climbing quickly or clipping pieces of protection. The Petzl Neox finds the sweet spot on this spectrum, using a spinning wheel to reduce friction. This allows belayers to feed slack quickly and still provide a safe belay in the case of a leader fall. It is our preferred device for lead belaying.

Performance Comparison

Catch and Bite

The Petzl Neox provides a secure catch using the same camming device that other popular active assisted-braking devices use. When the climber falls, the upward force of the rope pivots the camming wheel, pinching the rope and arresting the fall. The harder the rope is pulled, the more the camming wheel pinches the rope. This camming mechanism works as well and never concerned us during our testing period.

The spinning wheel around the camming device introduces a key difference compared to other well-known ABDs. The initial (low) force of the rope being pulled out of the device simply spins the wheel, rather than engaging the cam. In the event of a lead fall, this force quickly overwhelms the spinning wheel, which uses a spring to stay in place. This pivoting and engages the camming function, which pivots the device and pinches the rope. Compared to other ABDs, this initial spinning movement provides a bit more “rope slip”. If the user is familiar with other ABDs, this rope slip can come as a surprise at first. However, rope slip isn't necessarily a bad thing, as it produces a softer catch.

Lowering and Rappelling

The lowering function on the Petzl Neox is the same lever that is used on other popular ABDs. When the climber is hanging on the rope and the cam is engaged, a plastic lever is pulled back to open the camming device. This allows rope to slip through the device, which lowers the climber. This function works well on this device, and we never had any concerns about control of the brake rope while lowering.

Rappelling with this device is performed on a single strand in the same way that a climber is lowered. The Neox offers plenty of control and security when lowering. One caveat, which also applied to other similar ABDs, is that rappelling adds significant wear and tear to the aluminum where the brake strand is bent around the device. Normally, we don't care about this too much, but since this device is so expensive, we prefer to rappel using a different device than to wear out the Neox. Other ABDs use steel where the brake strand runs over the metal, but that isn't the case here.

Feeding Slack

The Petzl Neox is truly revolutionary in the way it allows the belayer to feed slack quickly without engaging the rope-pinching mechanism and short-roping the lead climber. Similar to other ABDs, the rope is threaded around a pivoting camming wheel, which pinches the rope when rotated. The Neox introduces a spinning wheel where the rope runs over the camming mechanism, which reduces the friction between the rope and the device. The simplified end result is that it's easier to pull rope around the bend in the device without accidentally grabbing the camming wheel and pinching the rope. We are impressed by how easy it is to feed slack through the device without using our thumb to hold down the camming unit, and we almost never locked the device and short-roped the lead climber during our testing period.

All assisted-braking devices must contend with the paradox that pulling slack out of the device when a lead climber falls and when a lead climber wants to clip a piece of protection are nearly identical motions. When two hands are used to feed slack towards the lead climber, the Neox's wheel spins and doesn't engage the cam, since the wheel is supported by a spring that fights back against gentle force. However, when a lead climber falls and exerts a high force on the spring, it compresses and the wheel rotates, which engages the cam and pinches the rope. It's an elegant solution, and it currently offers the best lead-belaying action on the market.

Weight and Bulk

The Petzl Neox is heavy and bulky. At 8.3 ounces (235 grams), it adds noticeable weight to any climber. As such, we don't recommend this device anytime it has to be carried while climbing, like on multi-pitch or alpine routes. Other ABDs are much less cumbersome and more suited to multi-pitch climbing, not to mention the super-lightweight passive brake-assist devices on the market.

For normal single-pitch climbing where approaches are reasonable and climbers leave their belay devices on the ground, this device is perfectly portable and the weight isn't an issue.

Auto Block

We were disappointed in the Neox's auto-blocking performance. The internal spinning wheel reduces friction between the rope and the camming device, and this wheel is supported by a spring that resists small amounts of force. Therefore, light forces that engage the cam in other ABDs do not engage the cam with the Neox. Specifically, many belayers are accustomed to the cam engaging when the rope is pulled tight to the climber. With this device, simply pulling the rope tight isn't enough to engage the cam, and slack may slip back out as easily as it was pulled in.

If the climber says “take” and weights the rope, the cam will engage, most of time: when belaying a climber from above, we noticed a tendency for the rope to slide right back out of the device without engaging the cam. This likely occurs because the spring that holds the spinning wheel in place is constantly trying to expand and push the wheel back into non-pinching orientation. As such, we can't recommend this device for belaying followers from above, since the cam doesn't always engage when the slack is pulled tight. It is slightly uncomfortable to pull up the slack on a follower, just to see it feed right back down again. This lack of visible progress-capture means the belayer has to be extremely attentive to keep the brake hand on the rope at all times.

Should You Buy the Petzl Neox?

The Petzl Neox is perfect for any climber (or climbing partnership) who spends a lot of time lead climbing. It is the best device for belaying a leader, period. If you've ever been short-roped while desperately trying to clip a piece of protection, you know how frustrating it can be. This device, when used correctly, nearly eliminates that phenomenon. The Neox also performs well when giving top-rope belays and while lowering, making it perfect for nearly every day of single-pitch climbing. It's expensive, but it's worth the cost to serious lead climbers.

What Other Belay Devices Should You Consider?