How to fit a Harness
The most important element in harness comfort is fit. As with any piece of gear or clothing that you wear (think about shoes, clothes, packs, or even bikes for that matter), it will never be truly comfortable unless it fits. Of course there are other factors that contribute to comfort and function, such as padding, gear loops, and general layout. But fit is the most important factor.
People come in an amazing variety of shapes and sizes, so finding the right size harness can be tricky. There are 3 critical dimensions that must be matched to your body to get a good fit: waist size, leg size, and rise length.
Most commercially available harnesses will provide good fit of the first 2 dimensions, waist and legs, but they all lack adjustability of the critical rise dimension. We developed the 3-D harness system to allow for independent adjustment of all three dimensions. The Metolius 3-D harness is the world's only adjustable-rise harness.
A properly fit harness should leave the user hanging in an upright position with approximately 20-30% body weight on the waist and 70 - 80% on the legs. Waist belt and leg loop sizing is fairly intuitive. Rise adjustment, however, is not so obvious, yet its accuracy is critical. (cont. below)
Rise is the distance between the waist belt and leg loops. It determines how much of your body weight is taken by the waist belt vs. how much is taken by the legs loops. If the rise on your harness is too short for your body, too much weight will be taken by the leg loops, and you could be flipped upside down in a fall. If the rise on your harness is too long for your body, too much weight will be taken by the waist belt, and a fall would be painful at best. It is easy to see how essential a well-fitting rise is to the comfort and safety of your harness. As you can see, finding the right harness can be tricky.