Everything You Need to Know About Climbing on an Auto Belay

Auto belays - these automated machines are great for climbing roped walls without a partner and for training endurance or doing laps on climbs, as you don't need a human belayer. 

You'll likely see them in most, if not all, indoor rock climbing gyms with top-rope walls. They are noticeable by a long tethered lanyard attached by an industrial carabiner to a triangular and brightly colored mat near the bottom of the wall. At the top of the wall, the lanyard connects to a large circular gadget that contains the automated belay mechanism. The triangle mat usually says something like "Beware of climber above" because it lays flat on the ground when a climber is climbing to indicate the climbing wall is in use. 

So how does an auto belay work if you don't need another person to belay you? Well, as its name implies, the mechanism is an automatic belay device. However, if you are interested in the mechanics of the machines, here is a brief explanation of the mechanics behind the two most popular auto belay brands: Tru Blue and Perfect Descent.

Note most auto belays use the same method of ascension; as the climber climbs, the lanyard is wound up into the device at the top of the wall via a retraction spring. Thus the differences we are discussing regard descension mechanisms.  

Tru Blue Auto Belay Mechanics

Tru Blue machines utilize a magnetic braking system. Inside the top of the device are two magnets and a rotor. When the climber's weight pulls on the lanyard during the descent, the force pushes the two magnets toward a metal plate on the rotor. The pushing creates an electromagnetic force between the two magnets and the magnetic plate, slowing the climber's descent. 

Perfect Descent Auto Belay Mechanics

Perfect Descent machines utilize a friction-based braking system. Inside the device, the lanyard, which the climber attaches to, wraps around a brake. When the climber lets go and begins to fall, their weight spins the brake opposite the direction the lanyard is bound, which generates centrifugal force and lowers the speed of the descent. 

Using an Auto Belay in the Gym

Although you may feel confident in your ability to use an auto-belay, please ensure you adhere to your gym's auto-belay training or certification process if it is your first time using one. Knowing your gym's procedures, how to properly clip into and out of, and safety requirements is critical before jumping head first to climbing with an auto belay. At most indoor climbing gyms, the training to use the machines is brief and will not take more than 15 minutes of your time. Usually, it consists of some combination of the following: video tutorial, video tutorial plus a short quiz, staff-led tutorial, and staff-prompted quiz.

Things to Remember About Auto Belays

The most crucial information to remember is that, before all else, ensure your harness is on correctly and that you have clipped into the proper loop on your harness. For a personal harness, you should clip into the belay loop and not the loops the rope goes through. If you are using a rental harness, then there is only one loop to clip. Additionally, ensure the carabiner locks properly before climbing. Most auto-belay accidents come from people not securing themselves properly or making other simple, avoidable mistakes. 

As with any new endeavor, using an auto belay for the first time may be scary. If trusting an automated machine to catch you when you fall is unsettling, first, only climb up a few feet. Then, take a test fall to get a feeling for falling without being high off the ground. It does take a second for the braking system to kick in, so you will initially be in freefall when you let go. However, you should feel the brake engage within a second or so. Once you are comfortable with what the descent feels like, then try to climb up higher and complete the climb.

One last important piece of information is always to ensure you only climb on the climbs denoted for auto-belay use. Even if you want to climb the route on the wall next to the auto belay, don't. This is because climbing too far to the left or right of the auto belay could damage the machine and lead to potential injury.

We've highlighted various safety points and risk management processes to keep in mind. Don't let them deter you from trying auto belays because the devices are truly an amazing training tool for training or having a solo climbing session (that isn't restricted to bouldering). So, next time you're in the gym, ask the front desk if you can give it a whirl.

Let us know in the comments below if you've used an auto belay and if you like them!