This is one light, breathable, and streamlined pack! It’s constructed of comfortable, highly porous, durable webbing that absorbs almost no water. It’s see-through, so it breathes like fishnet stockings (what, you’re not running in fishnets?). The weather during Quest for the Quest ranged from very humid and warm, to cold and raining. While my clothes were soaked for the entire race, the pack barely held any additional water weight by the end. Overall, the build quality feels really solid, and I see no areas of damage or wear after almost 80 miles, including many encounters with trees and rocks during the race (and one particularly creative fall in a river). It’s light at 7.2 oz, especially considering how solidly it’s built. Sure, there are packs like the Salomon S-Lab Sense Ultra Series and the Nathan Vapor Krar that weigh a little less; however, in my experience, these packs end up weighing more than their listed weight, since they’re primarily made of fabric and hold onto sweat more than the open mesh of the UltrAspire. I also found the way the pack fit (more on that below) and how well balanced it is made it feel lighter on than the already light specs–I liken it to a running shoe that may not be the lightest in your closet, but because of how well it works, feels that much lighter. In the end, if you think two or three extra ounces is really slowing you down in an ultra or trail race, then maybe just eat 3 ounces less of dinner before the race, or look in the mirror and say this, “I am delusional, I am not Killian Jornet, I need to stop being a weight weenie.”
Regarding storage, the front of the Momentum features two large open pockets that sit just below the chest and can hold bottles or flasks, depending on your preference. Neither are supplied with the pack, and it doesn’t accommodate a hydration bladder at all. At $79, I can’t blame UltrAspire for not supplying bottles, especially since most of us have a bunch lying around from other packs. For those that don’t, they suggest–and I wholeheartedly agree–using their UltraFlask 550, which is the best compromise between the utility of hard bottles and the comfort of soft flasks. Honestly, the only way these bottles could be better is if the openings were a touch bigger, and they sold alternate tops that had drinking straws, so you don’t have to remove the bottles to drink…but I digress. I’ve been able to get up to 22 oz. Bottles into these pockets comfortably, and there are elastic straps further up from the pockets to hold the drinking straws we’re starting to see on newer soft flasks.
Directly above the bottle pockets are two smaller pockets: a zippered mesh pocket on the left for small essentials (think keys and a credit card; not a phone or anything bulky) and a small water and sweat resistant pocket on the right that has a magnetic flap closure, apparently intended for rapid access to electrolyte pills (although you could also stash xanies in there…no judgements #WADA #zzzsport).
The sides of the vest had two medium-sized stretchy pockets, and I’ve been able to cram lots of stuff into them comfortably without it bothering my ribs or bouncing out on the run. During Quest for the Crest, I had four packets of Sword hydration powder, and a pack of Honey Stinger chews in the left pocket, and a blister kit, baby wipes, and my headlamp in the right pocket—both pockets still had room for more if needed. I’ve even crammed up to 8 gels into a pocket! I’ve seen some complaint about the location of the side pockets, but I had no issue with them, and I could even fit my iPhone 7 in them if I had too (which is good, because it won’t fit anywhere else besides the water bottle pockets, which don’t close).
Round back, the pack features two large water bottle pockets identical to those on the front, but these sit slightly lower down, near the kidneys. This means you could run with four of the 550ml UltraFlasks for a total of close to 80 oz. of water—more than enough for most situations. In testing, I ran an 18 mile run with four full bottles and was psyched at how evenly balanced the pack felt, and how nothing bounces at all. I highly prefer this setup to carrying bottles up front and a bladder in the back. In this setup, you’re less likely to use the bottles in the end for on-the-go hydration, but instead, you’ll want to swap it empty front bottles with full ones from the back as your run progresses. This is the first pack I’ve used where it didn’t bounce and still rode comfortably, despite having over 2 liters of water, food, and emergency supplies–and it still breathed well!
Above the rear bottle pockets, in the middle of the pack is a snug zippered compartment, meant to hold some extra layers and emergency supplies. I’ve managed to cram a jacket, mid layer, gloves, and emergency bivy in there, but you’re not gonna get multi-day storage here. It’s also not meant to be accessed on the run unless you’re Gumby. I am not Gumby, dammit.
Rounding out the storage are two small elastic loops hanging from the bottom of the pack, meant to give you quick access to folding trekking poles, should you desire to bring your cheating sticks along. So far this is best best solution I’ve found for keeping your poles stashed in such a way that you can actually retrieve them on the run without them otherwise bugging the shit out of you, or causing you to curse the French every time you try to stash your poles in your pack (I’m looking at you, Salomon, and your 4d pole system). It takes a few times practicing, but after that, hooking and unhooking my poles became simple.
The closure system for the vest is comprised of two elastic sternum straps that securely loop over small, red hooks on the right side of the vest. They’re easily adjusted on the fly to give you a looser fit if you’re hiking uphill, or a snugger feel if you’re barreling down the hill. I have a few issues with the straps and closures, which I’ll get to below, but overall I was pleased with this setup. The straps secured the pack nicely, but also molded comfortably to the chest, expanding and contracting naturally with my breathing efforts—especially helpful when breathing is labored AKA the entirety of my race.
The fit is obviously going to vary by body type. I’m 5’9”, 165 lbs., have a 38” chest, and what you might call an athletic build (let’s just be charitable and call it that). The medium fits me well, so I’d call it a true medium, as that’s what I take in most vests (for point of reference, I take an M/L in the Salomon 5-set). I don’t feel any construction along my back or sides when the vest is fully loaded, and the vest is low profile enough that I can easily wear my raincoat over it, which means I don’t have to take it off when weather rolls in (assuming someone’s nearby to get my coat out of the inaccessible rear zipper pocket). Between the sizing of the vest and the innovative closure system, I feel I can rapidly take the vest from snug to more relaxed fitting, which helps during a long race with lots of grade changes (and mood swings).
There are so many good vest options these days that there’s no reason to settle for a vest that chafes or bounces. I’m happy to report that this is one smooth riding pack with zero chaffing! The edges are all wrapped in a soft, velvet-like fabric, and overall it rides closely enough that I didn’t notice any rubbing, even when I had the straps fully loosened. At one point during Quest for the Crest I had 3 full bottles, a headlamp, a water filter, my jacket, 4 gels, 3 packers of sword, my trekking poles, and some random items (blister kit, iPod Shuffle, baby wipes, meds, buff) and was careening dangerously down a rocky river that used to be a trail, and the pack was almost invisible. Late in a race, almost any pack will start to bug me, but this thing rode smoother than Kenny G covering Michael Bolton.Shop UltrAspire Momentum
It’s surprising to me that, given how many different vests there are out there, companies continue to include legacy features that don’t have as much application today as when they were first thought up, to wit: the “Magnon Pill Pocket” on the front of the Momentum. If you’re going to be putting on a pack in the first place, it’s usually because you need storage for things you can’t easily carry in shorts pockets. I don’t see the need to devote key real estate to a pocket specifically dedicated to pills that not everyone is going to use. Sure, there was a time when everyone was told to take electrolyte pills; however, with the proliferation of sports drinks with electrolytes specifically designed for endurance athletes (Tailwind, Sword, Gu Brew, etc.) and the conflicting studies about the need for electrolyte supplementation to begin with (I’m not going down that road; please argue with someone who cares) why not instead make this another securely closing pocket where you could stash any old thing, not just a handful of pills. Given that so many runners are running with phones, it seems like an oversight not to put a secure pocket on the front of the vest to hold a phone. Both of the small pockets on the front of the vest could be taller, frankly, without increasing the weight of the vest that much, so this seems like a real missed opportunity.
The front water bottle pockets can technically take soft flasks; however, because there’s no cinch closure on them (like in Ultimate Direction packs) and the material isn’t stretch-to-fit like Salomon or Nathan’s newer packs, flasks tended to bounce out for me on the run. I didn’t find this a huge issue because, as stated, I’m a big fan of the UltraSpire UltraFlasks, which weigh almost nothing, ride snuggly in the pack, and are soft against the body. If you plan on using soft flasks, keep this in mind. There are two sets of elastic straps further up the vest from the bottle pockets: one set reflective silver and another set in black. Why are there two sets of these? It’s a mystery! Please to be explaining, UltrAspire? Maybe remove one and give us a cinching system on the bottle pockets so the soft flasks with straws you show in your promo video (and which I’d like to use) don’t bounce out of the pack on a downhill and smack us in the face like a jilted lover.
The rear water bottle pockets are a bit hard to reach at first. I got used to it after a couple of runs, but I wouldn’t plan on using them while running to rehydrate, as replacing the bottle is a bit tricky. Still, it’s an okay comprise considering how well balanced the pack is, even with 4 bottles full of water in it, innit. UltrAspire wants you to think of these rear water bottle pockets as general stash pockets; however, because there’s no way to close them, stuff can bounce out. I had to be careful to wedge my Katadyn BeFree water filter in at an angle so it wouldn’t be left behind somewhere in the Black Mountains during my race, and I did end up losing a cliff bar that would have come in handy when I was slowly crawling to the summit of Mt. Mitchell through what can at best be called a series of waterfalls, connected by short stretches of mud pits. I plan on sewing some velcro to the rim of each pocket, which should easily solve this problem (while still allowing for use with water bottles) but this seems like an oversight by the designers. In general, I think all four water bottle pockets need to have snugger/stretchier mesh that will conform better to a variety of soft flasks and bottles and need the option to be cinched closed so items besides bottles don’t shake loose on the run.
The closure system, while comfortable, can be a little fiddly to hook at first. Basically, you’re supposed to take the looped, black elastic cord and hook it around the red hooks on the right side of the vest, then tighten them by pulling on the small plastic tabs on the left side of the vest, by the top and bottom of the water bottle pocket. It really takes two hands to hook the straps on, and I’m not sure I could do it with gloves on in the winter. Not a deal breaker, as we’re not talking a major difference in time, but a minor annoyance. Tightening and loosening the straps is easy, and you can really cinch them down if you like it snug. Unfortunately, the tension on the straps does loosen a bit over time, especially if you’re riding with a fully loaded pack. It didn’t really affect the performance of the pack, and bounce didn’t increase much at all, but I think they need to strengthen the grip on the left side of the straps that hold the tensions. I applaud the designers on minimizing strap-flapping (a pet peeve of mine) but it can be tricky to extract the plastic pull-tabs you use to tighten the sternum straps if you’ve tucked them into the provided holes. Again, not a serious crime, but one to grow on.
Good thing this breathes well, because black is the color that absorbs the most heat from the sun. I’m probably nit-picking here, and I get that black is the safest bet for sales, but maybe give us something a bit cheerier.
Sizing is fine for me, but they only offer the vest in small, medium, and large, so I’m not sure how well it will work on a variety of body types, let alone women (at my current rate of beer intake, I won’t have boobs for at least 2 years). The sternum straps really do stretch well, so I can see it accommodating different chest sizes; however, I really can’t see how three sizes will cover all body types. I’m not saying it has to, but you’re going to want to try on a few sizes if you think you’re in between.
UltrAspire Momentum Conclusion
Not gonna lie, I had kind of resigned myself to being a Salomon pack fanboy, as I own three different iterations of the Advanced Skin 5 Set Pack. With the Momentum, things may have changed! For a stripped-down racing pack, this thing kicks ass. I can get enough gear in it for an all-day adventure, and while I probably wouldn’t use it for a cold weather adventure (because of lack of volume for necessary gear) I’m going to happily use it in the rest of my upcoming summer races, which I think speaks to the packs versatility, comfort, build quality. If you’re needing a bladder, then this is one to skip, and you’re also going to want to find something else if you need to haul tons of gear. Neither of these are issues for me, and as this was built–I imagine–more with racing in mind, I think the designers knocked it out of the park!
I’m surprised by just how much I like the innovative solution UltrAspire’s designers found with bottle storage for the Momentum. I also applaud their pole storage solution, and their choice of materials, as this vest, breathes extremely well, yet feels super solidly built. The closure system is a bit finicky to hook up, but once closed is really simple to adjust, and very comfortable. I was able to hold a ton of gear comfortably during all my runs with this vest, and more importantly found it easy to retrieve and replace items (barring rear water bottles, which eventually became better after practice). In the next iteration, I’d love to see the two small pockets on the front replaced with at least one pocket that could hold a smartphone (seriously, it’s 2018 folks) and something less specific to poppin’ pills. While we’re at it, give me cinch closers on the water bottle pockets and velcro on the back pockets, and I’m a happy camper. If you’re in the market for a new pack, I highly recommend this one!Shop UltrAspire Momentum
Thomas is the Founder of Believe in the Run and has always been a gear junkie, and when he fell in love with running, he also found a passion for the gear that goes with it. He has been reviewing running shoes and gear through Believe in the Run since 2009. Stats: Shoe size: 10.5 USA, Foot shape: Narrow, Midfoot strike, 35 Marathons, 13 Ultra Marathons, 2 Ironman 70.3