Gregory backpacks is one of the best backpack brands available. Having been in the business for over 30 years, they have learnt a thing or two about backpacking and have developed various backpack suspension systems such as AFS and CFS that make heavy load hauling a breeze.
Auto Fit Suspension is used in the mid-sized Triconi 60 and the extremely popular Baltoro 70. Looking at Gregory backpacks for women, which are designed to fit a women’s curves better than a regular pack, AFS is used in the Deva 70 and 60.
Custom Fit Suspension has been designed for heavy weights of up to 70 lbs and longer trips of say five days or more. Only the larger backpacks such as the Whitney 95 and the women’s Deva 85 can take this kind of capacity.
Looking at the actual technical details now, both suspension types feature Gregory’s Auto-Cant harness design. This is essentially a rotating plate on the backpack frame onto which the shoulder straps are attached. When you put the pack on, the Auto-Cant movement allows the straps to snugly nestle down into the contours of your neck and shoulder line perfectly rather than rigidly.
In CFS, a pull-tab by your waist is hooked up to a 5-point adjustment, which allows you to change the angle of the waistbelt as it rests on your hips to a comfortable position. When you put an AFS pack on, this hip angle adjustment occurs automatically which helps keep your center of gravity aligned when you’re on the move.
The backpack frame is also different between CFS and AFS. CFS is made up of two vertical stays and one hollow anti-barreling cross-stay. This gives CFS packs incredible load bearing capacity without losing shape. AFS is made up of one vertical stay and an upper load-lifting panel providing this frame design with effective weight transfer of upto 50lbs.
In summary, to some degree you could say that there is no choice in the backpack technology. For example you can’t choose the Baltoro 70 with CFS. CFS is just not an appropriate suspension for a 70 litre pack. Essentially, there is a balancing act in play between backpack strength and flexibility that Gregory have already figure out.
But don’t worry about the physics. All you have to do is enjoy it.