This review is based on months of testing with 17 of today's most popular belay devices, but it rests on a 12-year foundation that goes back to when we first started examining the product category. Four different climbers have played the role of lead reviewer of belay devices over that time, and it is remarkable how little variance they have found in their testing. All the belay devices tested were purchased by GearLab on the retail market, and the reviewers had no financial incentive to score any product over another. Our conclusions are based entirely on our interactions with these devices. We sought out opinions from friends and acquaintances, but anything we couldn't prove ourselves we either left out or mentioned the source. Here's how we specifically tested each model for our various comparison metrics.
Catch and Bite
By climbing with each device regularly we got a good sense of how quickly and strongly each one engaged when a climber fell or took on the rope. We used skinny 8.5mm lines and thicker workhorse ropes in the 9.7-10.2mm range to see if there was a performance difference and also compared how hard we had to hold down on the brake hand to hold the weight of the climber. We also scoured the climbing literature and reported on some interesting tests by the German Alpine Club that compared the relative braking strengths and device engagement for various assisted braking devices. With the increasing popularity of passive assisted devices, and some manufacturer claims that they perform as well as an active device, it was interesting to see some lab tests that compared their effectiveness and showed their weaknesses.
Lowering and Rappelling
We rappelled and lowered with each device dozens of times, and would switch devices between routes to get that side-by-side comparison of how smooth they felt relative to each other. We assessed each device's various modes to see how well they worked, compared to how they are advertised.
Feeding Slack
For this category, we noted the smoothness of the pull and the complexity of the belay technique. We tried to keep an open mind with each device and not judge it by our first use, but rather how it felt after multiple days spent using it and practicing the proper technique.
Weight and Bulk
This was likely one of the least “subjective” metrics in our testing process, as the scales don't lie! We weighed each model on our digital scale and also considered how large the unit was.
Auto Block
While we tested the autoblock devices on multi-pitch routes, we also conducted an auto-block resistance test indoors. For this experiment, we set up each device in auto-block mode on a hanging scale. Then we pulled 10 meters of slack rope through while recording the weight on the tared scale. The actual number measured isn't significant. Instead, the relative difference between devices is what we focused on. All devices were in brand new condition, and we used the same Petzl Attache carabiner every time. The results were surprising, demonstrating how much resistance some devices actually add. We encourage you to play around with your equipment because your preferred rope or belay biner could give you different results. We also noticed that wear could have a big impact: worn-out devices gave 15-20% less friction than a new one.
