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May 9, 2014 Comments (3) Anton Krupicka, Featured, Gear Reviews, Training

Ultimate Direction AK vest 2.0

If you’ve been anywhere in the trail running or ultra marathon community, or have taken a look at race pictures within the last year, you’ve definitely seen one of Ultimate Direction’s Signature Series packs. It seems that they are quite a popular vest series. We were recently given the opportunity to play with the updated Anton Krupicka (AK) signature vest. Here’s our look at the AK Vest 2.0.

Whether it’s on AK himself or one of the dozens of runners at each event wearing this minimal vest series, it’s clear that it’s gotten around. And for good reason. This is one of the most versatile minimal vests that we’ve tested. We found that its original design as a minimal vest can change gears with the introduction of a 2L bladder. It worked great as an hour long quick-run pack but also performed well as a non-supported multiple hour pack. This was vital and helped this vest score major points with our testers. Here’s what they had to say:

Average number of miles using the vest: 120 miles


Running High in the Ultimate Direction AK Signature Series Vest

Fit & Comfort- 4.0

“It fit and held together well once I got it right. The materials used some kind of ultra running magic that allowed the pack to maintain shape and rigidity but stretch at the same time. But the bottles did take some getting used to”

Overall, there couldn’t be much negative to say about the fit and comfort of the vest. The 2.0 addressed a few minor changes to increase the comfort from the original AK Vest. Most notably, the side pockets were removed to prevent the underarm chaffing that occurred previously, it’s a ‘plus’ for the reduced chafing, but a bummer to lose the convenient storage space. Just as with the original, the adjustability of the side straps and chest straps allow the fit to be adapted to most body types and the lightweight but sturdy materials decrease the movement and bounce of the vest once it’s securely strapped in place.

Unfortunately this is a very polarizing fit. The bottles, especially the round bottle UD offers, tend to rub any protruding ribs and can cause some major irritation and even bruising if you can’t get the fit just right. It was remedied by one of our testers by switching to different, flatter bottles.


AK Vest on Mount Olympus in Utah

Adjustability- 4.0

“By adjusting the straps and spending the time to get the fit dialed in, I was able to get extremely close to what felt like a custom fit”

With even 4’s across the board the adjustability really helped out to make up for what may seem like initial discomfort. While the AK Vest was designed to fit one way, Buzz and his team at UD made sure that it would fit more than one body type. Smaller testers felt that there was too much strap to play with and that the excess strings could be felt whipping around if not tied down and knotted up. Once you’ve found the sweet spot, consider trimming up the side straps for a smooth fit (not too much now, need to save a little space for the holiday pounds!). Once adjusted, it did a great job at staying in place… even through a 48 mile run with quite a bit of wind and rain… and by quite a bit, I mean a downpour.

Storage Capacity 3.0

“It’s versatility really made up for the fact that this pack is considered a minimal pack. I did everything from 2 hours to 50 miles self supported”

There are no doubts about it, just like the signature runner himself, this is a minimal vest. Ideally meant to sustain you during short run and racing situations ideally. Small pack, less fuss, gets you a couple hours down the trails. While the storage space is more limited than other, larger packs, its versatility makes this an ideal pack for those that don’t like to be weighed down by too much gear.

The small gel pockets underneath the front bottle pockets were a struggle to fit two gels each. Meaning you were good for about 2-2.5 hours if you relied strictly on those with two front bottles and nothing in the back. Which isn’t all that bad in a racing situation, as I prefer bottles for ease of refilling at aid stations. If you needed something to last a little bit longer, like on an adventure run, this vest was also designed to be worked with a 2L bladder in the back compartment and the front bottle pockets made for some great storage room. Just make sure you strap it down or it could get a bit bouncy. Use the small stretchy shoulder strap pocket as trash storage or it fits an iPhone perfectly, which we’re sure was accidental…

The one gripe we had – why not make one of the lower pockets water resistant and add the pockets to the side of the bottle pockets (like the SJ and PB vests have) for extra gel storage? That would increase the gel capacity to 8 gels, which would be considerably high and still not take away the minimal feel of the vest.

Craig Lloyd Running in Zion National Park wearing the Ultimate Direction AK Signature Series Vest

Craig Lloyd Running in Zion National Park wearing the Ultimate Direction AK Signature Series Vest

Comfort When Fully Packed- 3.75

“I liked the pack better with a reservoir in back. However, I noticed it sloshed a lot unless I used the compression strap. It isn’t a bad thing, just something I needed to learn. Once I did that I enjoyed the vest much more.”

The materials that added structure did ultimately take away some minor ability to stretch. But like a web from Spiderman himself, it was surprisingly strong/rigid and surprisingly stretchy at the same time… all while being extremely breathable. Don’t ask me how they did it, but UD really sourced some great materials for this vest.

It seemed that this vest did a good job in this category. Once again, just make sure that it’s strapped down right where you want it, otherwise it might be a struggle to adjust on the go. And if you’re gonna use the bladder, learn how to strap it down properly like out tester mentioned above.

Sizing- 4.5

I felt like the sizing was spot on. I didn’t second guess getting the sm/m and it turned out to be just right.”

Sizing was spot on, mostly due to being able to adjust as needed in all the right areas. All of our testers ordered sizes based on our shirts sizes just to see how it would fit – and it worked out quite nicely.

AK Signature Series Vest

AK Signature Series Vest

Accessibility While Running – 4  

“I was quite impressed with the accessibility to the different compartments. Especially considering this was a minimal vest and they tend to be a little TOO tight and compact.”

It was unanimous. We all loved the accessibility to the front pockets and bladder while active. The improved bungees and straps in the pack added a good amount of security to any items added to the pack. From headlamps to crampons, the back pack was pretty accessible and accommodated for quite a bit of storage, though you do have to remove the pack.

The updated front bottle pockets are a little taller in the 2.0 version and hold the bottles in just the right place. Easy in and easy out makes these front bottle pockets pretty unique on the vest. It seems that the biggest complain fell to the gel pockets. They were so small and compact that even though there was a nice easy one handed access to the pocket, you still needed to use two hands to keep one gel in while you grabbed the other to prevent both from exploding out.

Overall Score – 4.2

If you don’t have the AK vest, pop one on and you’ll see there’s a reason that so many other people do. The multiple storage options, feather-light weight, and adjustability make it a no-brainer for the minimal vest-wearing trail runner.

Want to get one of your own? Visit the TAUR store to pick one up!


3 Responses to Ultimate Direction AK vest 2.0

  1. Scott K says:

    Scott with UD here. We understand that the round shape of our bottles can be less than completely comfortable for some. That’s why we’ve introduced our soft-sided Body Bottle, designed specifically to make our vests more comfortable. Check them out here:

  2. Shawn says:

    Nice. Are the pockets above the water bottles large enough to hold EFS Liquid Shot flasks? If so, would that interfere with moving the bottles in/out?

    • Jeremy says:


      The pockets are big enough to hold EFS Flasks. It is tight, but they fit. 4 oz UD flasks fit better. With flasks in there, getting the bottles out is definitely a problem. Plus, the bottles are pushed outward (forward) by the flask. The bottles already stick out more than I care for, so this is a deal breaker. The solution is to use the soft Body Bottles coupled with the UD flasks. This system works beautifully and it carries far better than with the hard bottles up front.


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