Whether you’re training, racing or run commuting, the ability to comfortably carry water, food, a jacket or other gear can be indispensable. Fortunately there are numerous quality running packs on the market today that provide a variety of options and carrying capacities whatever your needs. In this series of articles, I review several models from two of the leading running pack creators, Ultimate Direction and Salomon. I take a look at Ultimate Direction’s line in this article, and discuss Salomon’s packs in the next article. In a third article, I go into further detail about water bottles, hydration bladders, and filters that can be used in conjunction with these packs. I’ve put these packs through some serious testing, from run commutes to long trail runs. Here’s my take on some of the pros and cons of the different packs.
Ultimate Direction AK Race Vest 2.0
The Ultimate Direction AK Race Vest 2.0 has been my go-to low-volume running pack for weekly long runs over the past year. The pack is part of Ultimate Direction’s Signature Series that includes packs designed in conjunction with leading ultra-runners. AK are the initials of Anton Krupicka. Likewise the initials PB and SJ used in the names of the other Signature Series packs are those of Peter Bawkin and Scott Jurek.
The AK Race Vest 2.0 comes with two 20-ounce water bottles. However, I actually don’t use the 20-ounce water bottles with the AK Race Vest 2.0. The front water bottle pouches of the vest do provide ample storage capacity for these bottles, but I find two 20-ounce bottles to be too much weight in the front. When I do use water bottles in the front, I opt for Ultimate Direction’s 10-ounce bottles. But usually, I prefer to carry a 1.5-liter bladder in the back and use the front water bottle pouches to carry nutrition, a cell phone and sometimes a camera.
One of the pros of the AK Race Vest 2.0 are the numerous front pockets. In addition to the two water bottle pouches, there are two vertically situated pockets above and two horizontally situated pockets below. The water bottle pouches have drawstring cords to cinch shut, and the other pockets use Velcro closures. The bottom horizontal pockets work well for keys, ID, gels, electrolytes or an energy bar. The top vertical pockets could be used for a very small cell phone (smaller than what most people own) or additional nutrition or perhaps a bandana.
The back of the vest features a single large pocket that opens from the top. There is no zipper, just a small Velcro strap that provides minimal closure. The pocket can be used to stuff a rain jacket, some extra food or a water bladder. I usually use this space to carry a 1.5-liter Salomon soft reservoir. The pack is well designed to handle water bladders with loops that allow you to route the tubing over the shoulder. I can also stuff a light jacket into the back pocket in addition to the water bladder thanks to the bungee cords that allow for expansion or contraction. You could also stuff a jacket or other items under the bungee cords on the outside of the pack, if needed. The pack also features trekking pole and ice axe loops.
The AK Race Vest 2.0 comes in two sizes, and the side straps allow you to make adjustments to get the perfect fit. The more items you put in the pack, the more you’ll need to let out the side adjustment straps—and vice versa. The front chest straps provide further tightening or loosening. When well-adjusted and carrying 1.5 liters of water in the back, I can keep the front chest straps somewhat loose without encountering any bounce. The chest straps on this pack, unlike the Salomon packs, are not elastic. But the lack of elasticity does not interfere with breathing. In fact, I like the ability to cinch the pack to my body with the non-elastic straps, which provides more control over eliminating bounce with heavier loads (but contrast this to my review below of the Fastpack 20).
Pros:
- Excellent minimalist pack for carrying water/nutrition
- No bounce when properly adjusted
- Multiple options for carrying water
Cons:
- None
AK Race Vest 2.0 details:
- Volume capacity: 244 cubic inches / 4 liters
- Weight: 7 ounces / 198 grams
- Price: $100
- Ultimate Direction website
- Buy on Amazon
Bottom line: The AK Race Vest 2.0 is an excellent choice for long training runs or racing when you only need to carry water, some food, and maybe a few extra items such as keys, ID or cell phone.
Ultimate Direction SJ Ultra Vest and PB Adventure Vest
Given how much I loved the Ultimate Direction AK Race Vest 2.0, I bought the original version of the Ultimate Direction PB Adventure Vest thinking it would be just as likeable but with greater storage. Although the vest is well-built, I was sadly disappointed with the fit—or lack of fit. Unlike the AK Race Vest, the original PB Adventure Vest didn’t have any way to adjust the fit—namely, it lacked side straps.
Fortunately, I see that has been remedied in the PB Adventure Vest 2.0. But since I have not tested the new PB Adventure Vest, I will just note here that the PB Adventure Vest 2.0 (11 liters) as well as the SJ Ultra Vest 2.0 (7 liters) provide additional storage capacity and different types of pockets beyond the more minimalist AK Race Vest 2.0. If you are looking for more capacity than what the AK Race Vest provides, the PB Adventure Vest 2.0, SJ Ultra Vest 2.0, or some of the Salomon packs I review in the next article could be for you.
SJ Ultra Vest 2.0 details:
- Volume capacity: 427 cubic inches / 7 liters
- Weight: 11 ounces / 310 grams
- Price: $130
- Ultimate Direction website
- Buy on Amazon
PB Adventure Vest 2.0 details:
- Volume capacity: 671 cubic inches / 11 liters
- Weight: 16 ounces / 454 grams
- Price: $160
- Ultimate Direction website
- Buy on Amazon
Ultimate Direction Fastpack 20
The Ultimate Direction Fastpack comes in a 20-liter version and a 30-liter version. I was excited to try the Fastpack with the aim of finding a high volume pack capable of carrying gear for multiple day running expeditions as well as run commuting.
As the Ultimate Direction website states, “the Fastpack takes inspiration from our Signature Series vests, with its super stable and comfortable fit.” This sounds promising, especially given the amazing fit of the AK Race Vest 2.0 as I discussed above. But, as it turns out, I believe this is ultimately the downfall of the Fastpack.
The problem is that the Fastpack 20 is built to hold 20 liters (or 30 liters for the Fastpack 30) while the AK Race Vest 2.0 is a 4-liter pack. The basic design of the Signature Series vests simply does not scale up well to a high-volume pack. The main flaw, in my view, is that the Fastpack lacks over-the-shoulder straps. This is also lacking in the AK Race Vest 2.0, but the AK Race Vest 2.0 does not require these due to the low-volume nature of the pack.
However, once you start to fill up the Fastpack 20—and it is easy to fill with lots of gear—the added volume and weight creates substantial bounce. I experienced too much bounce running with a weight of only 9 pounds. Running with 14 pounds in the pack—which you could easily achieve if packing gear for an overnight trip—was not enjoyable at all.
The non-elastic straps—which I like on the AK Race Vest 2.0—become a hindrance, as well, since tightening them in an effort to eliminate bounce makes it difficult to expand the diaphragm and chest while breathing. One might argue elastic straps would be better, but I imagine those would only make the bounce worse.
In my experience with other packs, such as Salomon or GoLite packs, much of that bounce brought on by higher volume and weight can be attenuated with over-the-shoulder adjustment straps. In fact, over-the-shoulder straps are a fairly common design feature of many backpacks—not just running packs. If Ultimate Direction could at least add this feature, I imagine it would vastly improve the Fastpack 20.
Interestingly, in the promotional video for the Fastpack, you don’t actually see anyone running with it. Perhaps Ultimate Direction never intended it to be a running pack; nevertheless, their audience clearly consists of runners. For runners looking to carry up to the 20 liters of gear, I would recommend looking into some of the Salomon packs. The Fastpack 20 and Fastpack 30 are better oriented to hiking rather than trail running. So if your “fastpacking” involves some running in addition to fast hiking, you may want to consider other packs.
Pros:
- Lots of storage capacity
Cons:
- Too much bounce while running
- Lack of over-the-shoulder adjustment straps
Fastpack 20 details:
- Volume capacity: 915-1,403 cubic inches / 15-23 liters
- Weight: 1 pound 3 ounces / 535 grams
- Price: $150
- Ultimate Direction website
- Buy on Amazon
The bottom line: The Fastpack 20 is a quality pack with lots of storage volume, but it ultimately has too much bounce while running when filled. Best used for fast hiking rather than running.
Pack Comparison

Below is a comparison chart of the different packs examined in these review articles. Check out the next article for more on the Salomon running packs.
Disclosure statement: The products tested for these reviews were purchased independently. The author does not receive any incentive from the companies to use their products.