Which Pulley Carabiner is Best For You?
What is the best carabiner for a speed line set up? How about for a quick redirect for your rigging line while doing some light rigging? What about when you need a quick and easy mechanical advantage? Well for a long time, our only option was the DMM Revolver carabiner which worked well enough for most of the things above. But, it was lacking in a couple areas and because of that DMM and Petzl have both decided to upgrade with 2 of their pulley carabiners.
The DMM Revolver was used for a long time as a speed line carabiner because it was the only carabiner to feature a pulley sheave. For anyone that was around before the Rope Wrench, the Revolver was an integral part to the F-8 Revolver system that allowed us to work position on a single line! Those days are long gone now'. but it was still a revolutionary design at the time. So, the DMM Revolver featured a pulley sheave that was built into it to help reduce the friction that is usually created when a rope moves over the metal edge of a carabiner. This nice little sheave made it so speed lines flowed smoother and mechanical advantages were far more efficient than in times past.
One of the downfalls of the Revolver was it's pulley sheave. I know, I know, I just mentioned
how awesome and revolutionary it was but it was also really small. For a pulley to be highly efficient, i.e. reduce as much friction as possible, the pulley sheave needs to be large. According to most rope manufacturers, it is recommended that a pulley sheave should have an 8:1 bend ratio to be used with their ropes. That means a 1' line would have to be ran over an 8' pulley sheave! Obviously this is not practical for tree care operations so general guidelines point us towards a 4:1 ratio. Now for anyone that has looked at a Revolver sheave, they can see where the efficiency problem arises with such a small pulley sheave!
So, years after the initial release of the DMM Revolver, DMM has graciously released the super stylized Revolver Rig and Revolver Rig Twin carabiners.
These new carabiners feature a far larger pulley sheave which makes them far more efficient than their predecessor. The new pulley sheave is 26mm in diameter which allows for a 2:1 bend ratio on a 12.7mm or 1/2' line. That is a great number to see for efficiency! The Revolver Rig Twin features 2 pulley sheaves that are also 26mm in diameter allowing ropes between 5-8mm to be used for hauling task or a very efficient mechanical advantage setup.
Both the Revolver Rig and the Revolver Rig Twin feature textile friendly beckets on the bottom of the carabiner, under the pulley sheave. The design of the becket allows a carabiner or other textile to be used without interfering with the moving rope inside the pulley sheave. Again, this smart feature helps boost the efficiency by reducing any friction that could be created by small parts rubbing together. Both carabiners also feature a threaded captive bar that captures whatever cordage you have running through the pulley sheave and keeps it from riding up on the spine of the carabiner or cross loading the carabiner.
Petzl stepped into the pulley carabiner game as well with their RollClip carabiners.
The neat thing about the RollClip is the fact that Petzl decided to manufacture them with 2 different gate orientations. The RollClip A features a gate that opens directly into the pulley sheave allowing the gate to be opened and a rope dropped directly onto the sheave while the RollClip Z features a gate that opens towards the top axis of the carabiner allowing the carabiner to be easily clipped to another piece of hardware or cordage. This allows for different types of configurations with each carabiner or even more configurations when you combine the two!
The pulley sheave on the Petzl RollClip is 18mm in diameter so not quite as efficient as the DMM Revolver Rig. The 18mm sheave gives us about 1.4:1 bend ratio compared to the 2:1 of the Revolver Rig. The Revolver Rig does pack a bit higher price tag compared to the RollClip but they each have their own place in your kit!
All three of the carabiners discussed above can be used as a great addition to a speed line kit, a redirect, or for a quick mechanical advantage setup. Obviously if you are looking for a speed line carabiner or carabiners, which is obviously the case, then the most economical option is going to be higher on the list. But if you are looking to make a highly efficient mechanical advantage setup, in the smallest package possible, then a high dollar carabiner makes more sense. Regardless of what type of kit you are putting together, any one of these carabiners can help push your game to the next level with all the features they have packed into them!