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Reviews > Packs > Internal and External Framed Backpacks > Gregory Z45 > Test Report by Michael Mosack

January 07, 2012



NAME: Mike Mosack
AGE: 48
LOCATION: San Diego, California, USA
HEIGHT: 6' 1" (1.85 m)
WEIGHT: 240 lb (109.00 kg)

I've been backpacking for over 30 years, doing solo and group trips, with and without kids. I do day trips, weekenders and week-long or longer trips throughout the year. I backpack in all climates and seasons and in various locations within the USA, to include my favorites being Yosemite and Sierra Nevadas, California. I also have worked in Afghanistan for 4 years and rely on my backpacking equipment constantly. I go lighter whenever possible. Quality and reliability of items I carry are paramount to me over price and weight.



Manufacturer: Gregory Mountain Products
Sonora Gold image from website

Year of Manufacture: 2011
Manufacturer's Website:
Listed Weight: 4 lb 1 oz (1.85 kg) for the large sized pack that I am testing
Measured Weight: 4 lb 1 oz (1.85 kg)

Other details:

The manufacturer's website provides the following information...
•JetStream™ LTS Suspension with 3 waistbelt size adjustment options
•Ventilated and moisture wicking harness and waistbelt
•Roll top style main access
•Front zippered pocket and expandable front bucket pocket
•Dual hydration ports and sleeve
•Side, bottom and top compression
•Dual quick access waistbelt pockets
•Dual axe/tool attachment points with secure carry under compression flaps
•Tubular webbing ski loops
•Water-resistant zippers
•7001-T6 hollow aluminum stay
•210D double diamond ripstop and 210D x 420D HD flat weave fabrics

Colors available include:
Azul Blue, Tin Roof Gray and Sonora Gold
I am testing the Sonora Gold version.

Azul Blue image from website

Tin Roof image from website

Manufacturer's warranty as stated on their website says, "We build Gregory gear to last a lifetime and that's how long we stand behind it. We guarantee to you, the original purchaser, that this product will be free from defects in materials or workmanship, for as long as you own it". They also provide contact information and clear instructions for returning a defective product.


Quality of stitching and materials

The Gregory Z45 backpack arrived with an attached instruction card.

The Gregory Z45 backpack hereafter referred to as the "pack" or "backpack", is a standard top-load designed pack. There is an additional side entry access zipper that runs the length of the pack. This pack is recommended for a maximum 40 lbs (18 kg) load.

There are three sizes of this bag which I've listed below. I am testing the large size bag.

S= 2563 in (42 L)
M= 2807 in (46 L)
L= 3051 in (50 L)

S = 3 lb 12 oz (1.70 kg)
M = 3 lb 14 oz (1.75 kg)
L = 4 lb 1 oz (1.85 kg)

Torso Length
S = 16" - 18" (40.6 - 45.7 cm)
M = 18" - 20" (45.7 - 51 cm)
L = 20" - 22" (51 - 56 cm)

Close up of waist adjustment

Adjustment -
There are dual stabilization straps attached to the shoulder straps. These allow me to add stability to the pack load while moving. The shoulder straps come with long length webbing for a wide range of adjustment options. The waist belt has dual adjustments which are easy to manipulate even while wearing the pack. There are three waist adjustment points that are marked as S, M and L (small, medium and large) to accommodate differently sized people and is a very nice feature.

Access -
I can either access the pack via the top or through the side. These options consist of a drawstring closure at the top of the pack when I want to load or unload and quick access to items by going through the side zipper that runs the entire length of the pack.

Side access

Pockets -
There are dual side pockets (one on each side near the base of the pack for small easily accessible items or even approximate 20 oz (0.5 L) size water bottles.

There is a large compression pocket that I can probably shove a pair of sandals or a rain coat into. This pocket is designed with an hourglass type shape that helps to ensure that anything I put in the pocket will not fall out. There is also a mesh ventilation feature sewn into the bottom for drainage.

The top cover of the pack has a pocket that allows for storage of small items for quick access so that I do not have to open and search the entire pack. This feature is pretty standard on many packs that I have used. The top cover is removable, but does not convert to a day pack. There are webbing adjustment friction clips attached to the four corners, so it appears that in an emergency and with some ingenuity, I could fashion a day pack of sorts if I made a harness or similar waist belt.

There are two individual pockets sewn onto the waist belt that I can easily access while wearing the pack and moving. These are small and seemingly will only fit small items such as keys, compass, small bag of snacks, etc. Still this is a feature that I like.
Hydration tube access

Hydration capable features -
Inside the pack, there is a separate sleeve for an optional hydration bladder. There are two clips and an additional sewn loop at the inside top center to secure the bladder. This enables the bladder to hang inside the sleeve and not fall to the bottom of the pack. There are two openings (one at each side of the pack) located near the top edge shoulder area, for routing the hydration tube. This gives me the option of routing the tube either on my left or right side. There are additional loops sewn onto the shoulder straps that allow me to route my hydration tube so it does not flop all over the place and is easy to locate while moving.

Straps and securing points -
This pack has cinch or compression strap adjustments to squeeze the pack to help secure the load. It has loops and a securing point for hiking poles or an ice axe, etc. There are two adjustable straps on the bottom for securing additional gear (bed roll or pad, etc.) and there is an adjustable chest sternum strap. All webbing is routed through friction buckles and the clips are all side-release buckles of the same size and design. The only exception to this is the waist belt buckle which is larger to accommodate the wider waist belt.
Load transfer and ventilation system

Ventilation -
This pack utilizes the JETSTREAM LTS (Load Transfer Suspension). This system is designed to reduce the contact points of the pack to the body to allow me to stay cooler. The inside and undersides of the waist belt and shoulder straps respectfully, are constructed using a mesh type fabric to allow for maximum ventilation. The pack frame is curved to ensure that the pack does not conform to the natural curve of the body, but actually is opposite for added ventilation. Padding is designed to ensure that the majority of the pack is kept off of my back, yet provides support and stability. My initial impression is that it is quite comfortable when worn.


The Gregory website is clean and easy to navigate through. I did find that there were features available on the website when using Internet Explorer that would not work using Mozilla Firefox.

There is no listed MSRP price anywhere on the Gregory website. There is however, a dealer listing to help locate sources where I can buy this pack.

The website has a "Buy Now" icon that when clicked, provided me with 3 different dealers so that I could purchase this pack online.

There is a very convenient link to a PDF file download that takes me to the proper way to fit a Gregory pack. I found this link and file to be quite helpful. I was also impressed that the manufacturer provided this to ensure potential buyers had information to assist them in selecting the right pack for them. There is also a 360 degree view of the pack which is another website feature I like.
Side view image from website


The only instructions that came with my pack were on a small 4 page card that was attached to the pack and tied with a loop of nylon cord. The instructions provide a nomenclature listing of the features of the pack, a brief explanation of the JETSTREAM LTS Load Transfer Suspension, and step by step instructions on how to adjust the waist belt with detailed photographs.


So far, I have only filled my pack with pillows and a sleeping bag for the added bulk and to get the fit adjustments set. The pack feels very comfortable and was very easy to adjust. I like the design of the shoulder straps and the over all size. I travel a lot and it is important to me that my pack will fit into an aircraft overhead compartment. I do not like to check my backpack into the aircraft cargo hold. I have had way too many packs that came back opened or missing things or damaged. This pack will fit into the overhead compartment just fine.

Additionally, I like the easy access pockets on the waist belt for my knickknacks. One other comment I would like to add is the innovative design of the zipper pull tabs are curved which make them easy to locate and use.


I am initially quite impressed with this pack and look forward to trying it out. I have even gotten many comments already from my friends on the different product features and overall quality of my pack.

I would prefer to have better and more complete information on the website to include the actual MSRP (purchase price) and accurate dealer resources that actually sell this pack. Additionally, I would prefer to see that when I click on the dealer link from the "Buy Now" icon from the product page, that I can get directly to the product that I am looking for at each of the dealer websites I am sent to. Of the three dealer options I was provided, it appeared that only one of them actually sold the Gregory Z45 backpack.



During this testing phase, I have been in Nangarhar Province, located in eastern Afghanistan for the past two months. I have since spent over 20 days and nights in the field with my pack. The terrain is a harsh desert environment where temperatures have ranged from highs over 100 F (38 C) to night time lows of 55 F (13 C) although the daily temperatures are now subsiding as we get closer to winter in Afghanistan. The weather has been mostly clear skies and quite dry so far. The terrain is a mix of rocky mountains to sand and very fine dusty areas and the elevations have ranged from approximately 1700 ft (518 m) to over 6000 ft (1830 m).


I almost immediately began this testing phase traveling. I took 9 flights on airplanes and one on a helicopter to return back to my base in Afghanistan, from San Diego, California. During these flights, my backpack fit into the overhead compartments in every airplane. The only exception was that during my flight in the helicopter, I had to put my pack in with the rest of the cargo next to my seat. Every flight was a success and I had no issues with my pack or it being accepted as a carry on. I just love it when a plan comes together!

I do my best to travel as light as I can, but admit that I tend to also carry luxury items making my pack often heavier than I'd like. I am a true boy scout at heart and live by the idea of always being prepared. I'd rather have something and not need it than to need it and not have it I guess, but I am getting better. Gravity has gotten stronger with age and time, so my desire is to lighten up. My pack weight is currently around 40 pounds (18 kg), but I also carry military gear with me here, which is notoriously heavier than my techie newfangled gear often sitting at home waiting for my return.

I have been pretty happy with my pack so far. I did notice that the shoulder straps by design have a curve to them giving them a contour shape for fit. This feature works well when using the included chest strap to pull the shoulder straps together and hold them in place. I have in the past, often preferred to go without the chest strap attached and by doing so, have found that the shoulder straps have developed a twist in them as they tend to work themselves to my armpits. The edge of them almost cuts into the crevice of my armpit area. This is not a comfortable situation and one that I've found to be easily avoidable simply by using the chest strap. I just have preferred to not use one for years, but I am learning to change my mindset now and that's probably a good thing.
Gregory Shoulder Strap

Shoulder strap twist

I have not had any real problems with this pack to date. All of the zippers and adjustments work as they should and I am very comfortable while wearing the pack. One of the features I really like is the side access to the contents of the pack. I have used this more times than I care to think about while searching for something in the pack I packed near the bottom. It has been great not having to pull everything out and just enter the side of the pack instead.
Gregory contour fit


This is easily my most comfortable pack when I wear it correctly and with the chest strap connected. I hardly even notice I have a pack on during these times. I can not really say that the shoulder straps are a problem either. I can avoid the shoulder strap twist easily enough. I am loving how well this packs rides on my back and it ventilates very well. The hip belt adjustment allows me to get my fit right the first time and adjusting the pack is easy while wearing it.



During this testing phase, I have been in Nangarhar Province, located in eastern Afghanistan for the majority of the past two months. I have since spent 9 days with 2 over night trips with 3 nights in the field with my pack during this phase.

The terrain is a harsh desert environment where temperatures have ranged from highs over 80 F (27 C) to night time lows of 25 F (-4 C). Winter is coming in quickly in Afghanistan. The weather has been mostly clear skies but occasionally there has been rain and even snow at elevation. The terrain is a mix of rocky mountains to sand and very fine dusty areas and the elevations have ranged from approximately 1700 ft (518 m) to over 6000 ft (1830 m).


I am loving this pack. I have not had any issues with it during this phase. All of the zippers and fasteners work well and the pack remains comfortable as the day I first put it on. I have used the pack on missions with the military and it has performed as well or better than my military counterparts gear. Plus, mine is substantially lighter weight than theirs. Packing items in it is easy and retrieving items even easier with the available side entrance or top entry. The pack holds the load quite well and rides very nicely. I often forget it is on while walking. I have not had any issues with rubbing or hot spots while wearing this pack either.


I have nothing but praise for the quality and comfort of this pack and its features.
Some of my favorite features are as follows...
1. The JetStream LTS suspension system that allows very good ventilation and weight carrying ability. I often forget I am carrying a pack because it is so comfortable.
2. That it is hydration compatible and that there are openings on both sides of the pack to allow me to route the drinking hose from either side. Additionally, inside the pack there are two hooks and a loop to allow me options on how to connect or hang the bladder.
3. The side zipper opening that allows me entry deep into the pack's contents quickly.

If I were asked, I would offer a couple of ideas to the manufacturer for available future options...
My "wish" list would include the following...
1. I would have liked to have been provided an extra set of buckles (side-release and friction) in case of needed replacement or repair.
2. A small repair or patch kit.
3. An included rain cover.
4. To have the top cover convert to a day pack.
5. The hourglass designed shape of the large stretch mesh front pocket is a little restrictive for shoving things like a jacket into it. If the hourglass sewn shape was a little more oval or open in the middle, it would be better in my opinion. Although I had no problems, I was continually concerned that the stitching would be ripped by the force exerted on it in the middle area of this pocket.

I would like to thank Gregory Mountain Products and for allowing me to test this product. I feel very lucky to have had this experience.

This report was created with the Report Writer Version 1. Copyright 2012. All rights reserved.

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