UltrAspire Alpha 5.0 Review [Ultrarunner Tested]

Most Breathing Room on Climbs

Overall75

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UltrAspire Alpha 5.0

Fit9/10

Capacity6.5/10

Features7/10

Materials & Quality7.5/10

• Capacity: 6 L
• Fit system: Max O2 elastic sternum cord
• Hydration: Lower-chest bottle holsters
• Best for: Long, steep climbs where you are breathing hard

Bottom Line : The sternum cord stretches as your lungs do, so it never feels tight on a climb. Use UltrAspire's own bottles.

Pros

• Chest never feels restricted
• Low bottles keep the weight centered
• Magnetic rear pocket works one-handed

Cons

• Dense items can pop the magnets on big drops
• Tall, narrow flasks flop in the holsters

On the Long Climbs

The Alpha 5.0 was our choice for chest comfort. Its Max O2 sternum uses an elastic hook-and-cord system that stretches with the chest as the lungs work on steep climbs. On the longest grinds, our testers never felt constricted.

The bottles ride lower on the chest harness than on most vests, which keeps the weight of the water nearer your center of gravity.

The rear "passage pocket" at the bottom of the back closes with strong magnets, so a rain shell or headlamp can be grabbed one-handed without looking.

Two Limits

The magnets have a ceiling. They held through normal running, but jumping down steep drops with something dense inside, like a thick aluminum battery bank, forced them open.

The holsters are picky. They are short and wide, shaped for UltrAspire's flat-bottomed bottles. Tall, narrow soft flasks such as Salomon's flopped around.

Spec Sheet vs Our Test

• Capacity: 6 L.
• Fit: UltrAspire's ErgoFit shaping and Max O2 sternum, which stretched with our breathing as promised.
• Bladder: UltrAspire lists an insulated bladder compartment. Our testers ran it with bottles.
• Newer model: Amazon also sells an Alpha 6.0, which we did not test.

Should You Buy the UltrAspire Alpha 5.0?

Yes, if breathing room on climbs matters most to you. Use UltrAspire's own bottles, and keep heavy, dense items out of the magnetic pocket.

Compare With

• Salomon ADV Skin 12 review: our best vest for 100-mile races.
• Nathan Pinnacle 12L review: our best women's fit and easiest access.
• Ultimate Direction Ultra Vest 6.0 review: our best vest for wet weather.
• Salomon Active Skin 8 review: our best value training vest.
• Nathan VaporAir 3.0 review: our best bladder vest.
• Osprey Duro 6 review: our most stable vest under heavy loads.
• CamelBak Zephyr Pro and Nano review: our best vest for hot weather.
• Black Diamond Distance 8 review: our best vest for mountain scrambles.
• AONIJIE 5L review: our best budget vest.

See all ten in our best hydration vests guide.

Our Testers

This review was edited by Sean Williams and tested by our ultrarunning team.

• Sean Williams, Editor-in-Chief. Sean built the team of researchers and testers behind our reviews and edits every guide. His rule: we say what we actually found.
• Annie Brown, Tester. An ultramarathon runner, Annie tested our vests through 100k and 100-mile race preparation.
• James Brown, Tester. An ultramarathon runner, James ran the same block of self-supported mountain long runs, hot-weather tempo sessions and technical scrambles.