A perhaps illustrative case study.

I built the race pack specifically for wilderness racing, the Classic next year in particular.  As explicated before, the Golite Jam I used last year didn’t fit and was too big.  I also wanted to make a pack as light as possible without compromising functionality or durability (or spending money, thus no cuben).  Max load perhaps 25 pounds, a close, stable and slim fit for bushwacking essential.

100% VX-21 fabric.  Shoulder straps and lumbar mesh from my old 2011 Jam (the straps fit me absolutely flawlessly).  21 oz.  20 inches exactly from the bottom of the pack to the straps.  Back and front panels are 7 inches wide, side panels are 9 inch wide, bottom cut on a curve, pack depth is 30 inches (to fit the 27 inch long mid sections of my Werner Shuna).

Top is a simple drawcord cinch, with some 1.9 oz/yard silnylon.  It can let water in, but is easy to make and use.  Compression straps are 1/2″ webbing to save weight, top buckles are quick release for fast use with skis, and can clip together for full wrap cinch.  Not pictured here is the daisy chain on the back, which will work for trying stuff on, but will see use most often for tying the pack to the packraft.  There’s provision for a top strap, and a hole for a hydration hose.  Full length pad sleeve with 1/4″ foam pad.

A pack this small does just fine without load lifters.

One of the crucial features is the contour cut into the side panels.  The very bottom by the belt and the bit by the straps stick out further, which facilitates a back hugging fit.  Even with a frameless pack such things make a big difference.

Subtle details add up.  Note the method strap attachment to the bottom corners, which double as abrasion protection.  Unlike just about every other pack I’ve made, this one does not have a doubled bottom (we’ll see how long that lasts).

I still can’t get compression straps dead even.

The tow strap hip belt is attached only in the center and corners, which balances stability with the capacity to absorb dynamic movement.  One crucial feature is the long, triangular panels along the outside of the lumbar panel.  The back pad sleeve does not extend into wings, which then flex and wrap when the belt is cinched.  Very effective.

I haven’t used the pack a ton, and will update as it proves itself.  Based on past experience I’m pretty confident the suspension and harness will work out well.  The real experiment here is the lack of side pockets (or pockets of any kind other than the pack itself).  Pockets are heavy, and executing them well is a pretty substantial design challenge.  I’ve nailed them with the North Fork pack, but none of the other packs I’ve made.  This pack is to see if I actually need them.