A good, simple, light closure for a big (top circumference in excess of 40 inches) pack is somewhat difficult to do well. Volume in a big pack can fluctuate significantly, and pack height above the frame needs to be controlled so it does not go bobble-headed and flop around. Additionally, weatherproofing and easy access for accessories (which can be easily lost in a large main bag, are concerns, as is occasionally strapping bulky things up top. Lastly, weight reduction is important for big packs, which are meant to carry big loads where ounce counting is paradoxically most relevant. As a matter of style and design integrity, I try to keep even the largest packs below 4 pounds.
Three classic options (pictured left to right) are a rolltop, drawcord with lid, and drawcord with cinch straps. Rolltops are the simplest option, and provide easy volume reduction and compression, with good weatherproofing. Their disadvantage is that they use more fabric for the same capacity, relative to a drawcord, and without a lid usually don’t provide additional organization. Should one go with a rolltop which clips to cinch straps, rather than to itself, those straps add weight and complexity, and must be located such that they are effective with loads of various heights. Some companies do rolltops poorly by substituting velcro or snaps a properly stiff reinforcement, which is crucial for keeping the rolltop rolled when the pack is particularly full. I put 1/16″ HDPE sheet in at least one side of a rolltop when I build one, and do not find this to be overkill.
Drawcords are the more classic pack closure, provide the best volume/weight arrangement, provide the best durability,work well with oversized loads, and in smaller packs I find them to almost always be the less fiddly option. In larger packs this is not the case, mainly due to the need to control height and volume. Lids do this well enough, though they require 4 straps, need to shaped well, and keeping them from being floppy when the pack is near empty is difficult. The functionality of lids is great, but I just don’t like the added complexity and weight, and never feel the need for the more extensive pocketing which tends to go along with them.
This leaves cinch straps to keep the drawcord in check, and while this can be both functional and light, I’ve never had it work as well as I wanted. A single strap, a y strap, and dual straps in a variety of configurations; all created ears of the pack fabric and somewhat even compression. Plus, I do like at least a small top pocket to keep maps and snacks separate from the bulky main load.
My current experiment in this area is with a rolltop which clips to itself, coupled with the ability to run dual straps over the top (think sleeping pad or antlers) and a slash pocket right above the top of the frame. The pocket zipper is over 10 inches long, and a fat #10 vislon. To maintain the full opening on this pack, which I’ve found invaluable, the bit above the vertical zipper closes with velcro. It’s the best thing I could think of that would be pliable enough to roll tightly. Pictured above is the latest version of this pack and this pack. Revisions over the 2015 version include mouting to the Seek Outside Revolution frame, which vastly simplified construction and increased comfort with odd loads, as well as a #10 coil for the vertical zipper, and slightly fatter circumferences (49 top, 45 bottom, 40 tall). I also went to a non-floating, segmented compression scheme which provides tons of volume control, as well as the ability to lash stuff on and compress the pack bag, simultaneously yet separately. I did not change the use of X50 fabric, which is ideal for hard use, nor the essential idea of having an enormous bag into which one can fit just about anything. This bag is big enough for a five day whitewater packrafting trip, with PFD, drysuit, helmet, and the usual essentials all inside.
This fall I’ll report back.