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Gossamer Gear G4-20 Backpack Review

Gossamer Gear G4-20 Backpack Review

The Gossamer Gear G4-20 Backpack is a 42-liter frameless roll-top backpack that weighs 25 oz. Being frameless it’s best for carrying loads under 20 to 25 pounds and makes a nice ultralight backpack for multi-day trips and extended day hikes. In many ways, the G4-20 repackages many of the unique features of Gossamer Gear’s Mariposa 60 Backpack in a lower volume and lighter weight form for hikers who want its utility without its weight or added volume.

Gossamer Gear G4-20 Backpack


Ultralight Backpack

The Gossamer Gear G4-20 is a 42 liter frameless backpack that's fun to use because it's suitable for so many different types of trips from ultralight thru-hiking and hut-to-hut trekking to all day peakbagging adventures and fast-and-light overnights.

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Specs at a Glance

  • Type: Frameless
  • Top Closure: Roll top
  • Weight: 25 oz (includes 3.3 oz external sit pad)
  • Pockets: 5 + main compartment
  • Gender: Unisex
  • Ice ax loop: 1
  • Trekking pole holder: No
  • Hydration compatible: Yes, center ports but no internal pocket
  • Bear Canister compatible: Yes, vertical
  • Sizing: Three fixed torso ranges and hip belt lengths
  • For additional specs click for Gossamer Gear product page
The G4 is available in an attractive blue or Gossamer gear’s traditional silver color
The G4 is available in an attractive blue or Gossamer gear’s traditional silver color

The G4 incorporates a number of design elements that are common on Gossamer Gear’s other backpacks. It has a front stretch pocket that’s good for storing clothing layers and other items you want easy access to during the day. There’s an external sit pack pocket and a foam sit pad that’s nice to sit on when you want to take a break, although it has holes in it so its no longer waterproof like Gossamer Gear’s other sit pads. Finally, there are gear loops distributed along the seams of the pack where you can clip on items or attach cord/cord locks (sold separately) to create compression or shrink excess pack volume.

The G4 has a external sit pad sleeve and removable foam sitpad.
The G4 has an external sit pad sleeve and removable foam sitpad.

Modular Roll Top

The G4 has a roll top that can be secured with buckles and webbing straps to the sides of the main compartment or on clipped together on the top and held in place with a single top strap. All of the straps are removable, so you can choose which ones you prefer and remove the excess straps or keep them all in place. (Note: the side straps and the top strap are not interchangeable.) The roll-top is a good option, especially for a lower volume pack, compared to the over-the-top closure used on Gossamer Gear’s other packs, which can be awkward and to open and close if you need to access the main compartment frequently or prefer the simplicity of a roll top.

The G4 doesn’t come with side compression straps, but there are gear loops in along the seams so you can add your own cord for compression or to hold items alongside the pack.
The G4 doesn’t come with side compression straps, but there are gear loops in along the seams so you can add your own cord for compression or to secure items to the side of the pack, like fishing rods shown here. Gossamer Gear sells accessory cord and cord locks for this purpose.

In use, I’ve found that the side straps are awkward to use and run slack unless the pack is fully loaded, while the top strap is easier to use when the pack is partially loaded. The top strap is also useful if you want to carry a folding foam pad on top of the pack.

Pocket Configuration

The pack has five pockets in total, including two hip belt pockets(described below) and the main compartment. Above the stretch mesh pocket, there is a map-sized pocket on the front of the pack with a waterproof zipper. This pocket is large enough to hold personal items, such as ski goggles, keys, wallets, and electronic devices. It’s pretty handy.

The left hand side pocket is 10” high, while the right is 6” tall
The left hand side pocket is 10” high, while the right is 6” tall

There are two more pockets on the sides of the main pack bag, one 6″ tall and the other 10″. Both can hold two Smartwater bottles. You can reach both pockets while wearing the pack, although it’s much easier to pull bottles out of the shorter pocket unless you’re really flexible. The tall pocket is reminiscent of the tall quiver-style pocket on the Mariposa 60, but is much more accessible when the pack is worn. It’s good for stashing long thin objects like fishing rods or a Jetboil stove system. Both pockets have drainage holes in their bottom.

Backpack Suspension

Fixed Length Hip Belt

The G4 comes with a fix length hip belt that is sewn directly to the back of the pack and not removable or interchangeable like most of Gossamer Gear’s other backpacks. That said, the hipbelt size ranges offered have a lot of overlap and you should be able to get a good fit anyway. I still wish that the hip belt was removable because that’s a nice feature on a frameless backpack, but if that’s something you want, I suggest that you look at the Gossamer Gear Kumo 36 instead.

The G4 has one open mesh pocket and one solid pocket with a waterproof zipper well sized for a phone or camera
The G4 has one open mesh pocket and one solid pocket with a waterproof zipper well-sized for a phone or camera

The hip belt has two pockets. One is large enough to store a phone and closes with a waterproof zipper, while the other is an open mesh pocket good for storing snacks and items you don’t mind losing.

Shoulder Straps

The G4 is a unisex backpack with J-shaped shoulder straps. Plastic loops have been added to the shoulder strap that are compatible with Gossamer Gear’s shoulder strap pocket and other clip-on gear like an inReach Mini Satellite Messenger. I would prefer having daisy chains sewn to the front of the shoulder straps because they’re compatible with a wider range of pack pockets, but it’s not a show-stopper as they say.

Maximum Load

Gossamer Gear lists the G4’s max load at 30 pounds, but I think 20-25 pounds is a more realistic range. While the foam pad helps the hold its shape and the hip belt is sewn onto the pack, the G4 is still a frameless backpack and doesn’t transfer much to weight to the hips. The hip belt is wide and richly padded but it isn’t firm enough for significant weight transfer. This is totally in-line with what I expect from a frameless backpack, but it’s important that you understand that the G4 is an ultralight backpack and has a limited load capacity by design.

Comparable ultralight frameless backpacks

Make / ModelTotal VolumeWeight
Zpacks Nero Ultra 3838L10.3 oz
Gossamer Gear Kumo36L20 oz
Nashville Packs Cutaway42L17.5 oz
Pa'lante V231L, 37L17-19 oz
Osprey Talon Velocity 30L30L35.5 oz
SWD Ultralight Superior Frameless45L18.2 oz
Mountain Laurel Designs Burn38L16.5 oz
Gossamer Gear G4-2042L20-26 oz
Mountainsmith Zerk 4040L29 oz
ULA CDT54L27.1 oz


The Gossamer Gear G4-20 is a 42-liter frameless backpack that’s fun to use because it’s suitable for so many different types of trips, from ultralight thru-hiking and hut-to-hut trekking to all-day peakbagging adventures and fast-and-light overnights. It’s a roll-top backpack, making it simpler to use than most of Gossamer Gear’s other packs, with a permanently attached hip belt and lots of pockets, which distinguishes it from Gossamer Gear’s other frameless backpacks.  The G4 is heavier than many other frameless backpacks because it has a hip belt, making it a good choice if you prefer one on a backpack but want to shed some gear weight. That said, it’s important to understand that the G4-20 is a frameless backpack with a maximum load of 20 to 25 pounds, so you can’t carry as much weight as a similarly sized backpack with an internal frame or frame stays

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Disclosure: Gossamer Gear provided the author with a backpack for this review.

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  1. Hi Phil, long time reader 1st time poster.

    Really enjoy your reviews, appreciate the breadth and depth of things you manage to cover. One thing I would love to see is stats in metric as well. As a none American I don’t think I would like to know how much time I have used in life googling conversions around backpacking gear :P I find this a thing with manufacturers websites as well.

    • You should give me some credit. I’m the person who convinced Gossamer Gear to put liters in their backpack product names. Wish they’d stick to that convention.

      • Why thank you for that ? their site is actually pretty great in therms of that, consistent Keith figures for most things as well. Really handy

        • FWIW, I’ve given up trying to convince Hyperlite Mountain Gear to rename their packs in terms of liters and not cubic inches, even though it would be to their advantage.

  2. I recently was in the market for a frameless pack and decided against the GG. The main reason is the sewn in hipbelt, that I see as a design flaw. On a frameless pack, I see the belt as being optional at best, since the load transfer without a frame is minimal. Why they did not make the belt removable or offer an option with a 1″ removable belt is beyond me. Anyway, I ended up going with a Zpacks Nero that, at 38 liters, is a bit smaller than the GG but fit what I was looking for to a tee. It also weighs in at a crazy light 12 ounces with the removable belt.

    • Two things: I think they made the hip belt permanent so they can sell it in retail stores and my guess is that they also wanted a frameless pack with a hip belt since it’s removable on all their other frameless packs.

  3. This is a fun refresh of the 20+ year old G4 design. I have an original G4 and still use it occasionally. I agree that not making the hip belt detachable is a bit of a head-scratcher. I imagine it made manufacturing less complex and brought cost down.

    Question about the foam back/sit pad – does it improve ventilation over using a Nightlight or other GG pad?

    Also, it looks like the 42L volume is the main compartment (not including the extension collar) plus the mesh and side pockets. Good for folks to remember this is measured similarly to other cottage manufacturers and different from mainstream manufacturers (Osprey/Gregory/et al.) who typically rate just the main compartment or main+brain.

    • Hey JP. I’ve owned one of the old G4s and I don’t see the resemblance to the new model at all. :-)

      The total volume really is 42 liters – 30L in the main compartment and 12L in the mesh and side pockets.
      When Gregory, Osprey, Granite Gear, etc measure pack volume, they only measure the volume of *closed* pockets. There’s actually an industry standard for this.

      The new pad does not improve airflow. Yes, it has holes cut into it, but they lead to a solid wall of robic on the pack of the pack so it goes nowhere. Gossamer Gear doesn’t recommend using a (3 panel) Nightlight pad with their packs because it pushes the center of gravity away from your core too much. You’ll get much better results using one of their other single panel sit pad designs or if you put the nightlight on the interior of the pack so it’s a tube.

      • Thanks! I guess any frameless pack is going to sit right on one’s back and ventilation will be minimal – bit of an issue in the swampy mid-Atlantic May-Sep but OK other times of the year. The new pad is cheaper than their Airflow SitLight pad but GG’s verbiage gives zero clue as to which has better ventilation.

        I have occasionally used one of their 1-panel SitLights in the back, but the page for the Nightlight says:
        “Simply fold this pad up in the morning and store it in one of our backpack sleeves.” So I have done that. I don’t find it awkward but I’m also not bushwhacking (lunacy with an original G4 anyway), just using it on trail. Will have to try it around the perimeter as you suggest.

        I have an 1/8″ Thinlight which I use in combination with inflatables for some extra protection – could see using that as a tube.

        Thanks for all your informative reviews! I notice the Silverback is currently only $15 more – that’s a much different pack however, but I think the features are worth the weight. Or I might go with the Camo Kumo that’s $60 less and is much more comparable if less cavernous.

        Been tempted for years by the MLD Exodus. Don’t think this is the year however.

      • I really enjoy using the Nitelight pad as a tube inside the pack. It adds structure to the pack, is part of an ultralight chair, added insulation to my sleeping pad, and other uses.

  4. Weird (and awesome), my G4-20 came with two zipper pockets on the hip belt. Maybe they ended up adjusting the final product due to the feedback.

  5. I am looking at getting this pack but I can’t find if a bear can would fit. Do you think that the BV450 would fit comfortably for a 3-4 day hike?

    • Fit yes. Comfortable, no. You’ll feel the canister. If you want comfort get a pack that has a frame or a rigid back panel. This just has a wimpy foam pad. For example, an Osprey exos 58.

  6. Helpful review, thanks. I like the size of this, but am concerned about the frame-less aspect. how would you say it compares to gossamer’s gorilla pack. Is it just a tradeoff of smaller weight versus larger capacity and
    better structure? is one more comfortable?

    • The problem with a frameless pack is that it maxes out at 20-25 lb loads. The Gorilla lets you carry more. But you can always take out the frame in the Gorilla. It’s easy. The biggest difference between these packs really boils down to the pocket layout.

  7. How would you compare this to Kumo? I am thinking between Kumo or G4-20 as day packs (with the family, so a bit more gear) that could also work as overnight pack (with not the most ultra lightweight gear). Sizewise G4-20 maybe offers a bit more versatility whereas the removable hip belt on Kumo extends use case outside hiking.

  8. Another great review! Practical and useful! I note that. Gossamer has some great price reductions on some packs and tents right now as well!

  9. I was struggling with finding a serious pack that when nearly empty would fit underseat while flying, then when needed, unfurls into a dandy lightweight daypack. I think I found it!

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