We all use seat packs in different ways, that’s the beauty of bikepacking. There are two main styles, standard and harness systems. Both seem to work great, but I prefer the harness system over the standard for it’s versatility. I’ve written about this before, and it’s no surprise that many brands, including Alpamayo Designs, have the same philosophy with their Seat Pack. 

The Alpamayo Designs Seat Pack is large, maybe the largest we have tested. Some standout features are the capacity that it can handle, the unique attachment system, and the micro adjustability. It’s not the lightest saddle bag, but it comes in at a competitive weight for similar systems. If you missed our first look video on this product, here is a brief overview.

The bag has great overall usability. It may take some time to understand how you attach the bag to the saddle rails, but once you get that down, it should be rather easy for future installs. Packing the stuff sack off the bike really allows you to jam your belongings in to make full use of the tapered design. Because of the tapered nature, the majority of the weight doesn’t end up weighing down the end of the bag. I consciously make sure to pack it tight up near the tapered section to hold the weight closer to the seatpost, this ensures a more stable ride quality.

One other important step is to ensure that the velcro strap that connects the bottom part of the harness to the top is spread properly to fit the stuff sack or an aftermarket dry bag. This feature is really neat because it allows you to adjust the actual height of the saddle system. Once you figure out the proper height with your stuff sack, you really won’t need to touch the Velcro strap again, unless you put it on a different bike or use a different stuff sack with the harness.

The body of the harness is made out of hard plastic which creates a nice shape and allows for easy installation of the stuff sack. After you install the dry bag and clip the support webbing strap in and tighten it down, you will want to cinch the side webbing straps. It’s as easy as tugging down followed by an upward motion on the strap. This is where the harness system squeezes the bag to the bottom of the saddle to make an extremely snug fit. This webbing strap is not only accompanied by a buckle lock but also travels through a ladderlock, which will ensure that the straps do not come loose while riding, and that was indeed the case while testing this bag.  Once it’s tightened down, there are two webbing holder straps to ensure a nice clean look that won’t allow straps flying around.

The aluminum rail is sewn in under what almost looks like a seat belt material.

When looking at a bag I search for a number of characters that show potential for failing. Typically, the most susceptible parts are plastic buckles and o-rings. Almost all seat packs use buckles to connect the seat bag to the seat rails, and o-rings that accommodate a double back velcro system which connects the bag to the seat post. 
Having clipped and unclipped these buckles and tugged on the webbing straps hundreds of times, I have been pleased with their performance. They are quality buckles, that are built for this type of abuse. I have broken buckles in the past trying to tighten down bags to make the most secure fit, but with this design I found that the pulley system makes securing the bag rather effortless, which is something I appreciate greatly in a seat system.

Another area I look at are the high stress points, typically where the bag is bar tacked. Again, I found no issues in these or any areas of stitching. The professional and clean look of all the seams lend a bit of confidence in the product as well. Unlike some bags similar to this one, the HDPE plastic stiffener on the bottom has kept its shape without bubbling. I think that’s in big part to the aluminum rod that is sewn into the spine of the harness. Outside of those areas, the harness has showed some wear and tear, but because of the heavy duty nature, it is in great shape.

High wear areas were well thought out with the use of hypalon, a tough fabric.
A first in the bikepacking world, pads for your seat rails.You can also see the redundancy in the saddle rail connections with the Velcro followed by the webbing strap.

The overall performance of the bag is on par with some of the best seat systems out there. When riding we are looking for a stable bag that secures nicely to the bike, carries a load well, and is easy to use. If we had to rate it based on those 3 things, I would give it an 8.

The stability comes from it’s connection points and the webbing system, they were designed well, and you can tell it was not thought about overnight. The bag performs well on dirt roads, singletrack, and even snow. The big variable in the whole equation is how you pack your stuff sack. Because it is so tapered in the tip, I found that throwing my heavier sleeping pad up front, and packing my sleeping bag around it, helped keep the heavier portion closest to the seat post. The stuff sack is also very large, you might find yourself stuffing a bit too much gear in it, which I have noticed makes the back end feel a bit sluggish.

If I would change one thing on the bike it would be the stuff sack, and how wide it allows you to pack the bag. It also will no doubt allow water to seep in, especially in a consistent downpour, or in conditions like Scotland. If that is your destination climate, you will need to line the stuff sack with a trash bag. The stuff sac and harness does pack down pretty small if you are not carrying to much gear, so it would work as a great bag to commute with.

The best part of the Seat Pack is the versatility. I can’t tell you how many times I found myself just using this stuff sack to carry things around town, not necessarily on a bikepacking trip. In general, these systems are great for stuffing clothes in and creating a pillow, using the stuff sack as a bear bag and hanging it off a branch, and the ease of packing off the bike is a game changer to me. I’m not sure if I’ll ever go back to a non-harness system for casual trips again. 

The simple stuff sack that has many uses.

If you are looking for a multifunctional, adjustable and versatile saddle system that can carry a ton of gear, and feels solid on the bike, the Alpamayo Designs Seat Pack is for you. It’s not super light or small, but it beats using a rack and pannier system, especially if you plan on riding with it off road.

Technical Specs:

  • Minimum of 10 inches (25cm) clearance from saddle rails to top of tire (with rear suspension fully compressed if applicable)
  • Minimum length of exposed seat post is 5 inches (13cm)
  • Not recommended for ‘dropper’ seat posts
  • Note: For riders who tend to sit further back on their saddles than ‘normal’ you may experience slight leg rub
Note: We never tested this bag on a full suspension bike, so we cannot report on how it works with rear compression and potential rubbing.

The stuff sack and harness come in at 533 grams, and the system can be purchased for £85.00 which is currently (6/26/17) around $108 USD. Head to their website and to contact them to order.


  1. Simon Vincent

    I have been using one for a while now, and agree that it is a great bit of kit. The only negative for me, is that I feel that the bungie cord would be more use on the top of the bag instead of towards the wheel. Its a bit close on a 29er. Otherwise, its robust, functional and very well made.

    • Neil Beltchenko
      Neil Beltchenko

      Good info Simon, we really never used it because it was hidden down there, I could certainly see it being more useful on top.

  2. Good review. I’m very happy with mine. Great design and quality workmanship. I find that the bungie cord works well where it is. I use the cord to carry things like my thongs, a trowel, etc.
    I only use the seat pack on my dual suspension MTB and it has never touched the wheel even on the softest suspension setting.
    Besides the seat pack’s adjustability in terms of being able to adjust the Velcro to change its size and shape to fit different stuff sacks etc. I really like the fact that once the seat pack is secured, it doesn’t swing or sway or move in any other way when I’m riding.

  3. perfect information
    thank you

  4. Hi together

    We are using Alpamayo gear for our longterm bikepacking journey around the world and we love it. The material is highly durable and the design is smart. To solve the non-waterproof rear bag problem we just took a thin drybag in the right size, cut away the stiffer part from the top rim and the buckles and sewed it directly to the rim of the Alpamayo bag. This liner makes the bag perfectly waterproof and doesn’t affect the packing.
    Short work, great effect 😉
    Safe riding, Brigitte from bikepackground.com

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