Review: Edelrid Giga Jul Belay Device

Edelrid GigaJul
A prototype of the Edelrid Giga Jul that was on display at the 2018 Summer OR show.

The Giga Jul from Edelrid is the newest addition to their growing line of Jul belay devices. While it’s the most traditional of the line it is also the most unique, as strange as that might sound. Traditional in the sense that it can operate the same as the ever popular ATC or Reverso. Unique in that it offers an assisted belay mode with the flip of a switch, much like the Mammut Smart. This makes it incredibly easy and intuitive for people transitioning from a more standard, tube-style device. It’s not without a few drawbacks though.

Features and Specs:

  • Weight: 123g
  • Material: Aluminum and Stainless Steel
  • Type: Tube-Style Belay Device with Optional Assisted Braking
  • Rope Compatibility: 7.1mm to 10.0mm
  • Guide Mode: Yes

The Giga Jul joins Edelrid’s family of Jul assisted braking devices:

  • Micro Jul: designed for half and twin ropes
  • Mega Jul: designed for single ropes
  • Mega Jul Sport: designed for sport climbing with thicker single ropes
  • Jul2: designed for single pitch climbing at the gym or crag

How the Giga Jul Works:

The innovative Giga Jul works the same as a regular tube style device (think ATC or Reverso) when in Manual Brake mode, making it easy to operate. This includes when it’s used for belaying normally from the bottom of a pitch, when used in guide-mode / top-down belay and even when rappelling. However, move the switch over to the Assisted Brake position and it operates the same as the other Jul belay devices with assisted braking. This means that when rappelling the Giga Jul has to be activated to descend or to feed slack when belaying. Of course the top-down belay or guide-mode can only be used in the Manual position but it has an assisted brake anyway.

Optimal Single Rope Diameter:

An assortment of tube style belay devices.

The performance of a belay device is heavily influenced by the diameter and condition of the climbing rope used. The thicker and fuzzier a rope is, the more friction that’s developed through a belay device. However, different belay devices offer different geometries which means that they have different sweet spots when it comes to rope diameter. I measured the rope gap width for a selection of belay devices and have summarized them in the below table. Of course this isn’t the only factor that determines the amount of friction developed by a given rope diameter but does provide some insight into which devices work better for thicker ropes and which for thinner ropes. The Edelrid Giga Jul is firmly on the thinner end of the spectrum by the ATC Alpine Guide, which is specifically designed for half and twin ropes.

Rope Gap Size of Various Belay Devices:

BD ATC Alpine Guide (half and twin ropes) 11.5
Edelrid Giga Jul 12.5
Petzl Reverso 13.0
Mammut Bionic Alpine Belay 13.0
Edelrid Mega Jul 14.0
Grivel Master Pro 14.0
DMM Pivot 14.0
GrandWall Equipment Gimli 14.5
BD ATC Guide 15.0
Beal Air Force 3 16.5

* measured midway along slot as shown in photo

Measuring the rope gap.

Not surprisingly, the sweet spot for single ropes with the Giga Jul lays at the bottom end of the spectrum in the 8.5 to 9mm range. Thicker ropes seem to rub on the sidewalls of the device, adding friction, especially when the device is used in a top-down belay. It’s less noticeable when belaying from below, but more on that in the belay performance section below. The Half and Twin ropes that I tested with the Giga Jul worked quite well though.

Belay Performance:

Now that we know how it works, let’s look into how well (or not) it works. To do this we will look at each mode, individually commenting on performance starting with the Manual mode belaying from the bottom, the Assisted Brake mode from the bottom and lastly a top-down direct anchor belay.

The Giga Jul set-up for assisted braking.

TR and Lead Belay in Manual Mode: When using the Giga Jul in the manual brake position to belay a lead climber it works much the same as any regular tube-style device. The switch is simply moved to the “M” position and the device is rotated such that the black wire cover is situated behind the device next to the belayer. With a single rope the device feeds out rope fairly well but taking in slack is less smooth as the rope rubs on the bottom edge of the side plates increasing friction. Not an issue with thinner half and twin ropes though.

TR and Lead Belay in Assisted Brake Mode: Flip the switch to the “A” position and rotate the device around and it’s in the assisted brake mode. As in the manual brake mode the Giga Jul actually feeds rope fairly smoothly and quite easily. However, the same side-rubbing issue is found when taking in slack using a single rope, making it a bit less smooth.

A top-down direct anchor belay with Edelrid’s Giga Jul

Top-Down, Direct Anchor Belay: When belaying a second up directly off an anchor with the Giga Jul, the rope seems to rub on the edges of the device even more than when belaying from below—even with skinny, sub-9mm single ropes. I think this is due to the sharp, non-beveled edges along the top of the side plates. The bottom edges have a slight bevel facilitating a smoother belay from the bottom. Of course this means that the friction will slowly improve over time as these edges get worn through use. As with the other belay modes, half and twin ropes did not experience any additional drag issues, but of course they’re much thinner at 7.3 to 8.2mm instead of 8.7 to 9.5mm single ropes.

Rappel Performance:

Rappelling on the Giga Jul in assisted braking mode.

In Manual mode the Giga Jul rappels much the same as any tube style belay device and provides a smooth ride so long as it’s paired with a nice round carabiner. It really shines in the assisted brake mode though! The rappel is quite smooth, not at all jumpy like some assisted brake units can be and definitely smoother than the Mega Jul. A real win as it eliminates the need for a personal prussic as a back-up, providing a quick and efficient yet smooth decent.

It’s worth noting that when rappelling in the assisted braking mode friction cannot be increased by adding an extra carabiner. Because of the way the carabiner sits in a small cut-out of the side, the extra carabiner actually pulls the rope out further and reduces friction while defeating the assisted brake. A definite lose-lose!


Some wear can be seen on the bottom of the middle side plate. Because the device is quite narrow ropes tend to rub along the bottom edge when belaying.

The Giga Jul utilizes a hybrid design combining steel and aluminum. The sides plates are constructed of lightweight aluminum that are attached to stainless steel braking grooves and slider. This means that the high-wear areas are quite abrasion resistant though a bit on the heavy side. The device will likely outlast any traditional all-aluminum belay device but won’t last as long as an all-steel unit like the Mega Jul. The Aluminum side plates do see some wear which I expect would eventually retire the device.


With all the different belay devices on the market it can be hard to decide on a particular one. You can gamble on something new that requires a bit of re-education or stick with what you already know. However, assisted braking devices have come a long way in recent years and are definitely worth considering the next time you replace your worn out ATC, Reverso or similar device. One of the great things about the Giga Jul is that it’s quite intuitive and easy to use, not a bad option so long as you’re climbing on skinny lines.

Pros: Intuitive and easy to use, very smooth assisted brake rappel, works great with half and twin ropes

Cons: Heavy, lots of friction with thicker ropes and top-down direct anchor belays

Overall: A very cool device that I’ve thoroughly enjoyed playing with. I especially love the smooth assisted brake when rappelling and often take it with me on routes requiring technical descents or half ropes. However, if I’m using a single rope I’ll also bring a stitch plate so I don’t need the Giga Jul for belaying my second up.

Black Sheep Adventure Sports was provided with a test sample for review but of course this did not influence us in any way.