Welcome! Ultralight backpacking is my passion, and keeping up on new technologies, gear, and techniques relevant to UL backpacking is what floats my boat. I'm always looking for the lightest, most functional gear to improve a lightweight or ultralight backpacking kit, and report my impressions and field testing results here. For hikers wanting to keep up on the latest and greatest ultralight backpacking gear, this is a good place to hang out. Also, there is a lot of information here (and on our informational website Southwest Ultralight Backpacking) on useful techniques and backcountry etiquette -- food for thought for hikers wanting to lighten their load and their impacts.

My goal for Ultralight Insights is to understand, test, and report on new technologies and gear of interest to lightweight and ultralight backpackers. It's a passion after all, so we just plain enjoy talking about it. I hope readers will add their own wisdom and comments, respond to my questions, ask their own questions, and correct me if I get something wrong. Happy hiking! Will

Monday, August 4, 2014

First Look: Gossamer Gear 2014 Mariposa Backpack – New Fabric and Lots of Nice Upgrades

By Will Rietveld

The Gossamer Gear Mariposa, their largest volume backpack at 70 liters, first appeared in 2004. Now, in August 2014, Gen 4 will arrive. It has come a long way. One can compare it with the evolution of a trend-setting car model, like the Toyota Prius. We are now in Gen 3 of the Prius, with each new generation dazzling us with advanced design, new technologies and features, better performance, more comfort, and more reliability. But the basic concepts have not changed. The Mariposa follows this same evolution.

Mariposa Genealogy

The original Gen 1 Mariposa was constructed of silnylon, featured two carbon fiber arrow shafts in sleeves on the backpanel to enhance weight transfer, and allowed the user to pad the 4-inch wide shoulder straps and hipbelt with clothing (or use provided lightweight foam pads). The outside pockets were all mesh. The measured weight (size Medium) was 17 ounces.

Then came the Mariposa Plus (Gen 2) constructed of a more durable grey ripstop nylon. It retained the straight carbon fiber stays, stuffable shoulder straps and hipbelt, and mesh pockets. Measured weight was 20.5 ounces.

The 2012 Mariposa (Gen 3) made further advances by introducing Gossamer Gear’s 140 denier Dyneema Gridstop pack fabric, a one piece contoured aluminum stay, a new Over-The-Top closure, fabric side pockets, and eliminating the option of stuffing clothing in the shoulder straps and hipbelt, while retaining their wide width. Measured weight is 28 ounces.

Now, in August 2014, the latest (Gen 4) Mariposa debuts, which is the subject of this article. How has it changed, and how much weight has been added?

What’s Different?

The new Mariposa is an upgrade, not a makeover. The pack has the same dimensions, volume, sizes, and basic features. There are a few bigger changes and lots of smaller ones. Overall, the new Mariposa is more elegant, professional, and refined.

The main changes are:
  • The Mariposa is now constructed of Robic fabrics; the previous 140 denier Dyneema Gridstop exclusive to Gossamer Gear will be phased out.
  • An internal hydration sleeve with two hose ports has been added.
  • The shoulder straps are narrower and thicker, with spacer mesh on the inside.
  • The hipbelt is wider and thicker, also with spacer mesh.
  • New stretch mesh on the pad sleeve and front pocket.
  • A trekking pole holder has been added to the front of the pack.
  • Webbing cinch straps replace the cord/buckle to hold down the top cap.
  • Cord loops are added to zipper pulls on the hipbelt pockets and top cap pocket.

So how do these changes affect pack weight? Not much; by my scale the pre-production Gen 4 Mariposa is only 0.9 ounce heavier than Gen 3; size Medium weighs 28.9 ounces without the external bungie system.

Fabric Changes – What is Robic?

As you can see, the 140 denier Dyneema Gridstop fabric of Gen 2, which was touted as “the ideal lightweight backpack fabric”, has been replaced in Gen 3 by Robic fabrics. Robic, made by South Korea’s Hyosung Corporation, is designed for applications where very high resilience and durability are needed. It surpasses Nylon 66 in tensile strength, tear strength, puncture resistance, and abrasion resistance. According to the manufacturer, this fabric is 100% high-tenacity nylon that can easily retain its original exterior even after long periods of use. The "old" Dyneema Gridstop contains super strong Spectra fibers in a grid pattern, but the rest of the fabric is ordinary Nylon. Bottom line, Robic is more durable than Gen 2’s 140 denier Dyneema Gridstop, lighter weight, and more cost effective. Gossamer Gear uses 100 denier Robic in the body of its new packs and 100x200 denier Robic in abrasion areas.

Photo Tour of the Gen3 Gossamer Gear Mariposa

The backpanel view shows the Mariposa’s new narrower, thicker shoulder straps, which are more female friendly. The new ones are 2.5 inches wide and 5/8-inch thick, replacing the 4-inch wide ¼-inch thick straps that was too wide for some people. The hipbelt is now 4.5 inches wide and ½-inch thick, replacing the previous 4-inch wide ¼-inch thick belt. The pad sleeve mesh is a bit lighter weight and a looser stretch. The sternum strap is nicer webbing then before and the whistle is gone.

The frontpanel view shows the new webbing straps (blue) to snug down the top cap, new mesh on the front pocket, and trekking pole holders (lower left).

The left side of the pack still has a large, tall pocket.

The right side has two pockets as before. Overall, the four outside pockets will hold a lot of gear and clothing.

The Over-The-Top lid is retained. The zipper pull on the top pocket, and hipbelt pockets, now have a cord loop that is easier to grab.

Bottom view. The SitLight pad provided with the pack overlaps the hipbelt, providing a padded lumbar area.

Close-up of the new narrower/thicker shoulder straps, which are identical to the ones on the new Gorilla backpack.

Close up of the spacer mesh on the inside of the new hipbelt. The new belt is wider and thicker than the previous one, and is interchangeable with the Gorilla.

The attached hipbelt pockets are the same size as the previous version; cord loops have been added to the zipper pull to make them easier to open.

The outside pockets on the Mariposa will swallow a lot of gear. My entire gear kit will fit in the outside pockets of this pack.

Even the “smaller” side pockets on the Mariposa are big and will hold a lot of gear.

First Impressions

Based on my experience with previous generations of the Mariposa, and my testing of Gen 4 so far, following are my initial impressions:
  • Pack Weight. On my scale, the new pack weighs 28.9 ounces in size Medium. That is a gain of only 0.9 ounce (based on measured weights) from Gen 3, which is extraordinary considering the changes (mostly additions) made to the pack.
  • Materials. The new Robic fabric is impressive, and its specifications indicate it should outperform the previous 140 denier Dyneema Gridstop. This is one of the first applications of Robic fabrics in backpacks, so it needs some time to develop a track record. Switching to lighter weight Robic fabrics was the key factor to offset the weight gain from adding several comfort and convenience upgrades.
  • Refinement. The new Mariposa really looks professional and dialed in for the lightweight backpacker. The word “Spartan” no longer applies. The new Mariposa provides loads of volume, comfort, utility, and convenience for a sub-2-pound backpack.
  • Utility. This is a very functional backpack, with a total of seven external pockets to organize your gear and make it readily available on the trail without having to dig into the interior of the pack. The three fabric side pockets and mesh front pocket will hold a huge amount of clothing and gear.
  •  Pack Volume Compression. The Mariposa does not have any traditional side compression straps (as the new Gorillia pack will have). Rather, as with previous generations, an external elastic cord compression system for the front and/or sides of the pack is provided, which basically squeezes the pack to a smaller size. For a discussion of this issue, read my article LightweightFrameless Backpacks State of the Market Report 2011: Part 1 – Choosing andUsing a Frameless Pack. On the Mariposa, the asymmetric side pocket design (a tall pocket on one side and two shorter ones on the other) makes it very difficult to add conventional side compression straps without interfering with the pockets.
  • Frame. The Mariposa has a removable inverted U-shaped, contoured aluminum stay that slips into sleeves on the backpanel. For its light weight, the contoured stay contributes a lot for transferring weight, retaining pack torso length, and contouring the pack to the user’s back. The Mariposa is a big pack (70 liters), and filling that entire volume usually adds up to a weight of 25-30 pounds or more, so the Mariposa needs an appropriate frame to effectively transfer that weight to the hips. In my limited testing carrying 20 pounds, I found the new Mariposa’s improved suspension system, in combination with the removable stay, helps a lot with weight transfer and carry comfort. 

 Important Tip for Pack Selection

  • When comparing Gossamer Gear packs, many buyers will notice that the new Mariposa backpack weighs only slightly more than the new Gorilla, so they will reason “why not get the Mariposa so I will have plenty of volume when I need it, and the cost is not much different either.” Don’t do it!! Unless you really need a large volume pack, you are much better off choosing a pack that matches the volume of your gear kit plus room for 5-6 days of food (see the above referenced article). The Mariposa lacks a good pack volume compression system, so it will not carry that well when partially full. It is far better to choose a smaller volume pack, like the Gorilla (which has good compression), that will be closer to full most of the time, and compressed, compared to carrying a larger volume pack that is not full most of the time. Bottom line, many people overestimate the pack volume they need; its best to take the time to accurately determine the pack volume actually needed (its usually smaller than you think) and avoid the error of purchasing a pack that is too big.


  1. There have been many comments concerning the lack of waterproof zips on the hip belt
    and top pocket. My Mariposa (2012 ) pockets always get soaked inside in the rain. Now have
    small plastic bags inside which help a lot. Many other makers use water resistant zips.
    Wonder why GG don't offer same.

    1. Very few backpacks have water-resistant zippers on the hipbelt pockets. One reason is those zippers are stiff and require two hands to open. If they were used, GG would likely be getting complaints that the zippers are too stiff. Will

  2. I use a gen 3 Mariposa and absolutely love it. This gen 4 version seems to address the only thing I might find fault with, which is the shoulder straps. These look much more comfortable and much more sturdy. However, the only time notice the "flimsiness" my gen 3 shoulder straps is when I've put too much into the pack which is not really the pack's fault.

    Thanks for the great review and great pictures. I may just have to upgrade...

  3. Is this made in the USA?

  4. Will this take a bear can (Bv500) sideways?
    Nice review!

    1. I don't own a bear canister, so not sure. I believe so. Anyone else care to comment who uses a bear canister?

    2. Wow,
      I just two fingered a reply and it disappeared,Anyway I have a gen 2 and it carried a Bearickade Expedition horizontally fine for the parks duration of my pct section last year.The outside pockets are great given the areas I was in.
      A fabulous pack but due to two back surgeries I moved to a lighter, less volume pack.
      I'm going to convert it so my 5'1 wife can use it.
      Thanks Will for your articles here and elsewhere.

  5. Can you clarify this statement?
    "The pack has the same dimensions, volume, sizes"
    I may be comparing an apple to an orange, but they don't appear to be the same volume?

    Mariposa Ultralight Backpack
    Capacity (Size Medium) -- 3,894 c.i. (63.8 l.) total

    Mariposa Ultralight Backpack Dyneema
    Capacity (Size Medium) -- 4,244 c.i. (69.5 l.) total

    1. Hi Nicholas, yes they don't appear to be the same size in the photos because of different scales. But the dimensions of the newest Mariposa are the same as previous versions. The volume has been specified as about 3800 cubic inches in the past, but I measured its actual volume a few years and found it to be 4,200 cubic inches. So the volume is 70 liters plus or minus. Will

  6. I've been using my Gen 3 for 2 years now, but Wow - I'd love the new version. Nice review. Questions: The trekking pole holders appear poorly placed - if the stretchy front pouch is full, it appears it will be in the way of the pole extending upwards. Can you respond if you have used this feature and if it works as intended? Also, some have commented that the shoulder straps look "more sturdy". I thought just the opposite when I saw the close-up photo. It seems any burr or twig will snag on the mesh covering of the pads (both shoulder and hip). What's your sense of durability of this mesh material? I ditto the waterproof zipper comment above - but assume that is a cost concession. I'm puzzled by the change from cord to strap top-flap fasteners - why? Looks like more than 0.9 oz to me... Loosing the whistle is fine - it didn't work that great anyway.

    1. I did not test the trekking pole holders, so can't comment. My opinion is that the shoulder strap and hipbelt mesh is quite durable, but it will take long-term testing to answer that. Regarding water-resistant zippers on the hipbelt pockets, very few mfrs use them, but it would be nice for hipbelt pockets to be waterproof since they are not protected in the rain. I think the main issue is these zippers are stiffer to operate, so it would be more cumbersome to unzip the pockets. I believe the cord to buckle connections to the top flap on the previous version were not popular, thus the shift to webbing. It does add weight. It appears that designing pack features gets down to weight versus convenience, and convenience often wins out.

  7. wow i guess i can be proud to have and still use the gen 2 mariposa.. with all unnecessary strap etc material removed it comes in right around 16oz, superlight. it is a bit delicate and i dont know how many more trips itll handle but i have much enjoyed the ones so far

    1. The straight carbon fiber stays are the main drawback of the Gen 2 Mariposa; they don't contour to your back at all. Its not hard to retrofit it with the new countoured aluminum stay available from Gossamer Gear.

  8. So do you know when will the Gorilla Ultralight Backpack Dyneema be updated ??

    1. The Dyneema Gorilla is history; the new version, coming out now, is made of Robic fabrics that are more durable and lighter weight. My article explains what Robic is and how it differs from the previous Dyneema Gridstop.

  9. Looks like they just posted the new gorilla tonight! Looks cute! Question, is the internal pack volume the same for the mariposa as the gorilla? From the spec page it appears that the only difference is the size and number of external pockets. Can you confirm? I just got the new mariposa today, and love lots about it. I am concerned that it doesn't seem very compressible, the position of the lid clips makes it so that here is no compression by the lid unless the pack is stuffed. I am thinking of exchanging for a gorilla.

  10. The pack volumes are different; the Gorilla is 46 liters while the Mariposa is 70 liters, so the Mariposa is a much larger volume pack. On the Gossamer Gear website, under "Specifications", they detail the volumes of the main compartment and the pockets. I emphasized the importance of determining the pack volume you actually need; it does not work well to buy a backpack that has too much volume and then carry the pack only partially full most of the time.

    You are right that the Mariposa is not very compressible and the Gorilla is. You can use some light cord (not elastic) and cordlocks to add a zig-zag compression system to the sides of the Mariposa. That would help a lot with compression, especially if you tighten the side cords before you load the pack.

  11. As you note, when a pack is partially full, you don't have any top compression at all. Another reason for purchasing a pack that matches the volume of your gear.

  12. What are the capacities of different sizes (small, medium, large)? Are they all 46L? I'm considering the small one because I'm 5'2 but don't know if the capacity is even smaller than 46L....

    1. They are much more than 46 L. All over 65, if I remember correctly. You can check the website on this. What I can tell you is that the small is really small. I am a small woman (5' 3" with average proportions - not a long spine) and I had to return the small to exchange for a medium. It is true that my torso length is 16.5" - just into the medium category as noted on the GG website, so it is my fault I ignored this advice and ordered a size S. I just couldn't believe I would need a size M when I am consistently size S or XS in women's sizes.

  13. Can anyone tell me what the buckles on the bottom of the shoulder straps are for??