GREGORY Z PACK FIELD REPORT
(Anti Gravity Series)
By Michael Wheiler
February 28, 2004

Company Information:

Gregory
Company Web Site:  http://www.gregorypacks.com

Product Information:

Product:	Z Pack (Anti Gravity Series)
Size:	Large
Capacity:	3950 cu in/65 L
Advertised weight:	3 lbs 5 oz/1.5 kg
Actual weight:	3 lbs 9 oz/1.7 kg
Color:	Castor Gray
Year of mfg.:	2003
MSRP:	$169.00 US

Biographical Information:


Field Report:

Z Pack Specifications Provided By Gregory:

Suspension:	Sewn-in sport harness Gullwing Plus waistband FOAM-X hourglass frame sheet Chimney ventilated back panel Single hollow, removable ½" (1 cm) 7075-T6 stay
Access:	Top and side access
Exterior Pockets:	Pleated front "bucket pocket" with water resistant zipper Secondary front pocket with water resistant zipper Water resistant top pocket
Fabric:	140d Dyneema® body fabric 210d HT Nylon reinforcements
Stitching:	Center locking bar tack (a row of stitching that reinforces high stress areas)
Load Capacity:	25-35 lbs (11-16 kg)
Usage:	Ultralight weekend to week long travel
Interior Pockets:	One large enough for water bladder
Height:	Approximately 26" (66 cm)
Width:	Approximately 14" (36 cm)

My Initial Report contains a more complete description of the Z Pack with photographs and can be found at Initial Report .

Field Testing:

My first trek with the Z Pack involved a one mile (1.6 km) snowshoe hike in a driving wet snow storm as my Scout troop snowshoed into yurts in Harriman State Park.  On this trip, I carried the following items in the Z: 

Sleeping Bag	A Marmot Tundra (light weight down) rated to 30° F (17° C).
Clothes	Extra wool socks, extra thermal under ware, fleece pants, moccasins, and extra gloves.
Lighting	Two headlamps and an extra eight pack of AA batteries, a Brunton Lampray lantern.
Cook Gear	An MSR Pocket Rocket, a small coffee pot, a titanium cook pot, a PackFlat grill, a plastic bowl, titanium fork and spoon, insulated mug.
Fuel	A Coleman propane canister for the State Park's lantern in the yurt, a canister of MSR fuel for my Pocket Rocket, and a canister of Brunton fuel for my lantern.
Food	12 oz (340 g) of sirloin steak, one package of freeze dried garlic potatoes, one package of freeze dried corn, 2 breakfast bars, two packages of instant oatmeal, 2 packages of hot chocolate, a Snickers bar, and one apple.
Water	Two liters (64 oz) of water in Nalgene bottles.
Miscellaneous	A Brunton Helios weatherproof lighter, a compass, a book, a digital camera, two walkie talkies, and two hand warmers.

The total pack weight was 28 lbs (13 kg).  If one had been necessary, I could have stowed one of my tents on the inside of the Z and I could have packed one of my Therm-A-Rest pads on the outside under the compression straps.  The Z Pack fit snuggly but comfortably on my back.  The load carried easily.  Adjustments in the shoulder straps and hip belt were easy to make even in the dark during near whiteout conditions.  Even though we were hiking in difficult circumstances, the Z Pack felt balanced on my back as I trekked through the deepening snow on my snowshoes.  When we arrived at the yurts, by using the top pocket, the side zipper, and the exterior pocket, I was easily able to access the exact equipment I desired without having to take everything out of the bag.  Accessibility is one of the design features that I really like about the Z Pack.  I need to have everything organized in my pack and the added storage areas in the Z allow me to do that.

It snowed most of that evening and the next day as well leaving us with about 6-8" (15-20 cm) of new snow.  The Z Pack sat in the back of my pickup truck most of the day while we performed a service project for the Park.  By the time I got it home, the pack was soaking wet and most of my gear was at least damp.  Although the pack's zippers are waterproof, the sack's fabric is not.  Mental note to myself, "Get a pack cover."

In January, my family and I cross-country skied about two miles (3.2 km) round trip into Harriman State Park and stayed overnight in one of the yurts the Scouts and I had used the previous month.  I packed a nearly identical pack as the one I took on the first trip into the yurts.  The only difference was the food.  This time I carried much more and a different variety of freeze dried food for both meals.  I also carried a Therm-A-Rest mattress on the exterior of the Z Pack by securing it under the compression straps.  One of my daughters was going to sleep on the floor (the yurts have two bunk beds) and would be needing the pad.  Total pack weight on this trip was 36 lbs (16 kg).  Although I was on cross-country skis and felt much less stable with my feet strapped to slippery pieces of wood, I once again found the Z to be very balanced on my back--a characteristic I was very grateful for given my circumstances.  I once again noticed how easy it was to make adjustments to the pack on the go.  Upon arriving at my destination, unpacking and getting to needed gear was a cinch.  The only criticism I have regarding Gregory's design of the Z Pack relates to water access.  The Z Pack's design does include an internal water bladder pouch.  However, on short trips, I generally just take a couple of Nalgene bottles and there is really no readily accessible place to pack those bottles on the exterior of the Z.

In January, the Boy Scouts and I snowshoed into a spot near the Buffalo River where we had previously built snow shelters.  We stayed overnight in the snow shelters.  We were expecting colder temperatures on this outing and so I really pushed the limits for the Z pack.  I carried the following gear:

Sleeping System	A GoLite Fierce combination down/synthetic bag rated to 30° F (17° C) with compression sack and a Mountainsmith Wisp (light weight down bag) rated to 30° F (17° C) for a liner with stuff sack; two closed cell foam pads; small tarp.
Clothes	Extra wool socks, extra thermal under ware, fleece pants, a fleece HeadSok, a PsolarEX face mask, and extra gloves.
Lighting	Two headlamps and an extra eight pack of AA batteries, a Brunton lantern, and a candle lantern.
Cook Gear	An MSR Pocket Rocket, a small coffee pot, a titanium cook pot, a plastic bowl, titanium fork/knife/spoon set, and an insulated mug.
Fuel	A canister of MSR fuel for my Pocket Rocket and a canister of Brunton fuel for my lantern.
Food	One package of freeze dried spaghetti, a bagel, one package of freeze dried mixed vegetables, one cup of instant split pea soup, 2 breakfast bars, two packages of instant oatmeal, one plastic bottle of orange juice, 2 packages of instant cider, and one apple.
Water	Three liters (96 oz) of water in Nalgene bottles.
Miscellaneous	A Brunton Helios weatherproof lighter, a compass, a water purifying pump, water purifying drops, a digital camera, two walkie talkies, and eight large hand warmers for heating the sleeping bags.

The pack weighed in at 42 lbs (19 kg)--7 lbs/3 kg over Gregory's suggested limit.  I put one of the closed cell foam pads inside the pack and other was strapped to the outside via the compression straps.  By this outing, I was fairly comfortable walking in snowshoes with the Z on my back.  I like the way this pack rides.  Although the Z Pack was carrying a very significant load, it sat comfortably and adjusted easily.  I'm sure that I strained the pack's material to get all of this equipment in or on the pack but it seemed to handle the extra load without even a hint of damage.  It was fairly cold that evening--24° F (-4° C) when I crawled into my sleeping bag.  Inside the snow shelter, my thermometer read 32° F (18° C).  I leaned the Z Pack against the icy wall of the shelter near my sleeping bag overnight.  The cold did not seem to affect the bag in the least.  The zippers worked without difficulty and the fabric maintained its flexibility.

In February, I camped with the Boy Scouts at Kelly Canyon Ski Resort where we planned to downhill ski the next day.  Due the nature of the trip and cold temperatures, we drove to the camp site and I did not use the Z Pack for anything more than a piece of luggage to haul my equipment from the vehicle to our sleeping quarters.  The pack load was minimal and, as a result, I forgot to weigh it.

Likes:

(1)   I really like the accessibility of this pack.  I can access any of my equipment without having to take everything else out.
(2)   The Z is very comfortable on short trips.
(3)   The entire suspension system can be easily adjusted on the go.
(4)   It will carry its rated weight plus some.
(5)   It handles cold weather well.
(6)   So far the Dyneema body fabric is holding up very well.

Dislikes:

(1)   No external pockets for water bottles.  This will be less of a problem when I have a water bladder on board.

Unknowns:

(1)   Since I received the Z Pack after we had snow on the ground, I haven't had it on a long trek yet.  I will take it on a longer         walk when the warmer weather arrives but until then, I cannot comment on the Z's comfort rating during a long haul.
(2)   I also have not yet had the opportunity to see how well the chimney shaped back panels work at keeping my back cool         but I hope to have an opportunity to test that feature before the long term report is due.

Future Testing Strategy:  During the long term testing period, I will continue to focus on the following features of the Gregory Z Pack:
 
(1)    Harness and waist belt effectiveness, comfort, durability, and ease of adjustment on long trips; 
(2)    The effectiveness of the chimney ventilated back panel;
(3)    Ease of using a water bladder in the inside pocket;
(4)    Whether I can safely pack a week's worth of gear in the Z;
(5)    The ability of the Dyneema® material to withstand the normal snagging, scratching and tearing packs experience on the              trail; and
(6)    How water resistant the zippers are. 

In March the Scouts and I will be camping in the desert near Idaho Falls.  Since my assignment with the Scouts has recently changed, I will not be hiking or camping with them during the coming months as anticipated.  However, I also anticipate that my family and I will be doing quite a lot more hiking, camping and backpacking together.  We currently have plans for several day hikes and a 2 day backpack trip in the Sawtooth Range this summer.  I am making plans to climb Mt. Borah (the highest peak in Idaho) in August or September and will most definitely want a lightweight backpack for that trip. Most of these outings will be in very mountainous terrain--5,500-8,500 foot (1,670-2,591 m) in elevation.  During these outings, the Z Pack will undoubtedly get drug across the snow, snagged on numerous branches and scratched by many rocks.  I will report on how well it handles contact with Mother Nature.