The Seek Outside Gila 3500 (57L) is an 2 pound 15 ounce external frame backpack capable of carrying heavy loads, up to 100 pounds. It’s made with a waterproof laminate fabric called XPac which is more durable than Dyneema Composite Fabric (formerly called cuben fiber) and less expensive. While the weight carrying capacity of the Gila is overkill for ultralight thru-hiking, the comfort provided by the pack for heavier 25-45 pound loads is quite impressive. External frames are well ventilated, so sweating isn’t an issue. The wide hip belt provides an excellent wrap around your hip bones and doesn’t slip, while the stiff frame keeps the pack weight off your shoulders. Let’s take a closer look at what makes this pack tick.
Specs at a glance:
- 42-47 ounces (51.5 actual weight, measured)
- Frame: external, adjustable torso length
- Fabric: X21 XPac; other grades of XPac are also available
- Suspension is 500D Cordura and 3D spacer mesh. Hypalon and 500D Cordura reinforcements
- 14″ – 20″ torsos without extensions , 18″ – 21″ with 2 inch extensions.
- One size harness micro adjustable to any torso length within fit range
- Interchangeable hipbelts in three sizes, to fit waists from 29″ to 42″
- Max weight limit: 100 pounds
- MSRP $339
Internal Organization and Storage
The Gila 3500 is laid out like an ultralight style backpack with a roll top closure, a long rear mesh pocket, and side water bottle pockets. The rear pocket is made with heavy duty mesh to prevent ripping while the side packets are hard faced with 500d Cordura for extra durability. There are two webbing loops inside the pack bag to hang a reservoir with a single hydration port behind the shoulder harness.
The side water bottle pockets can hold two 1 liter water bottles, which are reachable while you’re wearing the backpack. The pockets have a fabric slit in the bottom to drain water, but you need to be careful not to put small items there, lest they slip out. There’s also an elastic cord with a cord lock that runs through the top of each side pocket, so you can cinch it tight and keep taller items like tent poles, a paddle, or fishing rod secure. The lower side compression strap runs above the side pocket so there’s no need to ever routed it through or over the pockets like other backpacks.
The Gila doesn’t have hip belts pockets, although they are available as an optional add-on. The outside of the hip belt has a pair of webbing straps to attach them to. Both of the shoulder straps have external daisy chains which are convenient for hanging a GPS or camera pocket.
External Attachment and Compression System
The Gila has three tiers of side compression straps that give you a lot of flexibility to lash gear to the side of the pack or compress your load. The webbing straps are not long enough to loop behind the backpack, although the hardware doesn’t prevent you from running you own webbing straps there (for example, to attach snowshoes to the back of the pack). The side webbing straps are attached using plastic gatekeeper clips, which are like bachelor buckles but with wire gates to prevent the webbing from slipping when the strap is not tensioned. You can open the gates while wearing gloves by simply squeezing the buckle, which will pop the gate open.
The Gila also has a pair of sleeping bag straps at the base of the packpack that can be used to attach gear, like a tent or sleeping bag, to the bottom of the pack. You can use these to hold a bear canister or strap it under the Y strap on top of the pack.
Backpack Frame and Suspension
The Gila 3500 uses the same adjustable length, external frame suspension system as all of Seek Outsides other backpacks. The frame and suspension system is nothing short of ingenious, providing a level of modularity and many types of adjustments that are not available on conventional internal frame backpacks.
Adjustable torso length
First off, the torso length of the Gila 3500 is adjustable by raising and lowering the height of the shoulder harness. If you have a very long torso, you can add vertical extensions to the external frame to make the torso length longer.
Adjustable load lifter angles
The angle of the load lifter straps is also adjustable so you can maintain them at a 45 degree angle. To change the angle, you raise or lower a buckle the runs along the front of the shoulder strap. Many high-volume expedition packs have this feature and it’s quite useful to counter loads that pull you backwards and off balance.
The external frame is made using aluminum tubing and slightly curved to conform to the curvature of your back. Being an external frame, back ventilation is good because there’s an air gap between your shirt and the pack bag.
The frame is extremely rigid and there is no sag of the pack bag against your back. If you want, you can lengthen the torso so that the entire load rests on your hips, very unlike an internal frame pack where the weight is always split between your hips and shoulders by design.
The pack bag is secured to the frame with webbing loops, locking nuts, and pole sleeves that keep it properly positioned. If you want, you can replace the pack bag provided with the Gila with a higher volume version sold by Seek Outside or attach additional accessories. Yes, this one frame works with many packs.
There is a horizontal stay positioned behind you back that keeps the pack bag from barreling or bulging into you back if you overstuff the pack bag. It’s quite effective. This can be an issue on any roll-top backpack if you try to over stuff or over compress it.
The padded hip belt is quite wide (5″) and provides an outstanding fit that won’t slide down your hips even if you wear it fairly loosely. It’s attached to the bottom of the frame and floats freely, conforming to your anatomy, rather than making you conform to its shape like many internal frame backpacks.
Seek outside changed their hip belt about six months ago (on all of their packs), shifting from a single strap and single buckle to two buckles, attached to two straps running along the hip belt. This was to remove a single point of failure, while improving the wearer’s ability to tighten or loosen the top and bottom edges independently. While the new hip belt does improve the fit, it adds two long straps to the hip belt which can get in the way of each other when you attach and adjust the hip belt. Seek Outside has a good video on their which shows how to manage these straps with tri-glides, which helps reduce their nuisance factor.
The Seek Outside Gila 3500 (57L) is an adjustable-length, external frame backpack that’s ideally sized for lightweight backpackers who want a ultralight-style pack that weighs less than 3 pounds to carry loads in the 30-50 pound range. This is a weight range that’s beyond what many other ultralight-style and cottage lightweight backpacks can carry today, but well within the Gila’s wheelhouse.
There are lots of good reason why people have to carry this much weight on a backpacking trip.
- Wilderness backpackers that don’t have easy access to towns for resupply have to carry more gear, food, and fuel
- Winter backpackers have to carry more sleep insulation, food, fuel and technical gear
- Guides, trail maintainers and other wilderness professionals have to carry extra communication, medical, and search and rescue gear
- Dads get stuck carrying their own gear plus their kid’s gear and food on backpacking and camping trips.
If this describes you, I’d recommend checking out the Gila 3500 and its adjustable length external frame suspension system. Carrying one of Seek Outside’s external frame backpacks is nothing like that old Kelty or Wenzel pack you carried as a kid. Based on the Seek Outside external frame, the Gila 3500 is well sized and appointed for lightweight backpackers who have to carry more weight than they might like, but appreciate the layout of an ultralight-style, roll top backpack pack.
Disclosure: Seek Outside loaned the author a backpack for this review.