Arc Blast 55L Backpack
Great pack and exceptional quality. This pack is a must have for anyone serious about backpacking and moving around light. Quality design and craftsmanship. Thank you Zpacks. Fine job.
Designed to hike along mountain trails, scale steep ascents, and weather those Appalachian rain storms, the ultralight Arc Blast is perfectly suited for the demands of long distance hiking.
Comfortably transfer your pack’s weight to your hips with our patented ‘Arc Frame’ system. The frame also creates a gap between your back and the pack allowing for air flow that helps keeps you cool.
Featuring adjustable shoulder straps, an interchangeable belt, and a variety of optional modular add-ons, the award-winning Arc Blast will allow you to tackle those long days on the trail with a durable ultralight backpack designed to fit you.
- Constructed from 3.1 oz/sqyd Dyneema® Composite Fabric Hybrid.
- Roll top closure (like our dry bags) keeps water out, and lets you roll down the top as your gear load shrinks. All seams and attachment points are taped, making the pack highly water resistant. We still suggest using dry bags for your important items like your sleeping bag.
- Comfy 3/8" thick by 2.75" wide padded contoured shoulder straps and padded belt. Both the straps and the belt have a daisy chain for clipping on items, and an adjustable position sternum strap is also included. The belt and shoulder straps have 3D mesh on the underside. This gives them a little bit more cushion, and the belt also has more texture for better grip.
- Side pockets are sized to fit 1 or 1.5 liter bottles. They are positioned low on the pack and slanted forward for easy access without removing the pack. The pockets have drainage holes at the bottom, and elastic that keeps them tight at the top.
- Large stretchy mesh center pocket is great for quick access items. Mesh also lets you dry wet clothing and gives you a clear view of your gear.
- Side compression straps are made from non-stretchy Dyneema® cord for squishing down the pack volume. They also allow you to stand tall items like trekking poles in the side pockets.
- A top strap, and base straps allow you to lash on extra items to the top or base of the pack. The straps come off if you don't need them.
- A centrally located Hydration Port is included to string out a drinking tube over either the left or right shoulder. It is just above/between the shoulder straps and it has a triangular cover to keep out water. A water bladder can either be hung from an internal hang loop or laid horizontally on top of your gear.
- The 55L pack size has enough space for 5-6 days of food and ultralight gear. The pack can be compressed down with the roll top and side compression straps for short trips or use the top strap and base straps to lash extra stuff to the outside for long carries.
- All standard Bear Canisters, including the Bearikade Expedition and the BearVault 500 will fit in the upper half of this pack standing on end. There is enough extra girth to either wrap a foam pad around the canister (if you use one) or stand a medium stuff sack vertically beside the bear canister.
- The short and medium size frames will fit into an airplane overhead bin with the top rolled down to the frame. The tall size frame may not fit unless you pop the vertical frame bars out of the pack.
- Our Flexed Arc Frame is is covered by US Patent No. 9,060,590
- Our torso height adjustment mechanism is is covered by US Patent No. 9,848,687
- All Zpacks gear has a two year limited warranty against defects in materials or workmanship. Please see our return / warranty policy.
- Made in the USA.
- Our ultralight Flexed Arc frame keeps the pack stiff so that most weight is carried on the hips instead of the shoulders. The frame pieces and mesh back panel can be easily removed or replaced.
- The frame is curved to allow air flow and keep your back cushioned from the pack's contents. You can adjust the curve by tensioning the mesh back panel. The recommended arch is about 2.5" (6 cm).
- The belt is attached directly to the bottom of the pack frame for the best load transfer.
- The belt is removable and interchangeable. If you lose weight or need to share the pack between people, the belt can be swapped out. Watch the belt removal video.
- The shoulder straps and load lifter straps are attached directly to the frame. Load lifters straps come standard on this pack.
- The shoulder straps can move up or down to adjust the torso height to a perfect fit using our patented torso adjustment mechanism. It works like a conveyor belt. This is great for sharing the pack between people, for growing teenagers, or for resale.
- The belt provides a full wrap around your back. No need for additional lumbar support.
- The belt is done with "V-Style" webbing so that the top and bottom circumference can be adjusted independently. This helps wrap your hips much more securely and prevents the belt from sliding down.
- Collectively, these features provide the additional load transfer necessary for loads up to around 35 lbs (16 kg).
Body dimensions: 7" x 12.5" x 30" (18 cm x 31.8 cm x 76 cm)
Volume: 55L (42L main body, 2.5L each side pocket, 8L center pocket)
Frame Height: Short 19" (48.3 cm), Medium 21.5" (54.6 cm), Tall 24" (61 cm)
Made with Bio-Based Dyneema® Fiber
Reduce your carbon footprint with DSM’s bio-based Dyneema® fiber technology. Sourced from renewable, bio-based feedstock, it is the first ever bio-based ultra-high molecular weight polyethylene (HMPE) fiber. Commit to sustainability and help reduce our reliance on fossil fuel resources and rely on the trusted performance of the world’s strongest fiber™. Click here to learn more about our sustainability initiatives.
Made in the USA.
.3.5 oz/sqyd Mesh
This is the mesh that we use on our backpack's center pockets. It has a relatively light weight for mesh, while being difficult to tear. It can withstand getting caught on branches and other typical abrasion that backpacks are subjected to. The hole size is a about 4 mm (a little over 1/8").
Weight: 3.5 oz/sqyd (119 g/m²)
5.3 oz/sqyd 3D Spacer Mesh
This mesh has a three-dimensional structure which allows airflow and adds cushioning. It has a tricot backing so you can't see clear through the holes. We use it on the underside of our backpack's shoulder straps and belts to absorb sweat, add cushion, and add grip. Our 3D mesh weighs less than most other types.
Weight: 5.3 oz/sqyd (180 g/m²)
Thickness: About 3/32" (2.5 mm)
To measure your torso height, you will need the help of a friend and a string or cloth tape measure.
Most hikers wear their belt near the top of their hips, however, it isn’t uncommon for hikers to position their belt higher or lower.
To ensure you lock in the perfect fit, we suggest putting a belt on over your clothes in the spot where you’d like to belt to ride. Start your measurement at the center of the belt where it meets your spine.
Lower your chin towards your chest. This will cause the C7 vertebrae to protrude at the base of your neck. The C7 vertebrae will mark the top of your torso height measurement.
Using the string or cloth tape measure, follow the curve of your spine up from the center of your belt to your C7 vertebrae. This measurement is your torso height.
The padded portion of the belt is 1" shorter than the listed minimum adjustment. For example a "Medium (30-36 inches)" belt has padding which measures about 29" tip to tip, and has a minimum adjustment circumference of 30". It is the recommended size if your actual measurement is up to 36" however the webbing extends further.
To measure your belt size, pull a string or cloth tape measure tight around the spot you’d like your belt to ride. Choose a belt with a minimum adjustment of a couple inches smaller than your actual waist measurement. This will leave room for you to tighten down the belt if you lose a little weight on trail.
The belts on our Arc Series packs are also removable and interchangeable. This will give you the ability to switch the belt out if your waist size changes or if you order the incorrect size by mistake.
Click here for full instructions on how to wash our Dyneema® Composite Fabric backpacks.
- Arc Blast
Carries like a dream
Love this pack!
Crazy light and versatile
This is such an incredibly comfortable pack. You can make adjustments to personalize the fit. There is no other ultralight pack with so much adjustability and versatility. It handles a Bear Canister comfortably and the belt is unbeatable, it’s form fitting with the double adjustments. I love the ventilation the flexible frame provides and how I can make easy fine adjustments between the belt, shoulder straps and load lifters while on the move. The pack is roomy enough for my gear and thanks to the side compression straps it has a clean, tight form. Excellent design! This is my favorite go to Sierra pack. The Arc blast keeps the load off my neck and shoulders, after a long day my shoulders and back feel great so I sleep well, so much better than other packs I’ve used.
ARC BLAST on my A.T. thru-hike
I can't say enough good things about the Arc Blast backpack. I chose this particular pack for my thru-hike because I wanted a lightweight framed pack that could comfortably handle a five day food carry. This pack is super light for a full featured pack. The frame did a great job of distributing the weight while maintaining a gap between the pack and my back for ventilation. Several people asked me about my pack during my hike. Most were impressed that a sub two pound pack could carry all my gear in such a compact form factor. The pack held up great with only a small hole in the back panel due to user error (a zipper on the back of my shorts rubbed against the material). The thing I liked most was just how comfortable the pack carried on my back. At age 51, I've tried many different backpacks over the years and I can honestly say that the Arc Blast is my favorite by a long shot. A lot of my friends carry frameless packs to save weight, but with this pack I don't have to sacrifice the frame to have a light pack. I definitely recommend this pack for anyone doing trips over three days.
That was a good purchase
I'm glad I bought this wonderful product. The back is not stuffy and it is very light. And cool
This system that does not get stuffy on the back is the best. And light. And it's cool.