Zerk 13 UL Daypack w/2L Bladder

Co-designed with Ryan Van Duzer, the new ZERK 13 pack stands alone as the ideal combination of lightweight durability, comfort, and accessibility. Lightweight, body hugging and compact; perfect for fast and committed multi-sport adventures.

Ryan Van Duzer headshot

From Ryan's DuzerTV website:

I'm a born and bred mountain boy from the foothills of the Rockies. Ever since I was a kid, I've loved playing in the dirt and exploring the great outdoors. My passion is getting people motivated to challenge themselves, all while making this world a kinder place.
Check out Ryan's website and Youtube channel.
Color
Darknight

Don't be a jerk, ride with the Zerk. Its Duzer approved and he's a really nice guy.

Co-designed with Ryan Van Duzer, a prominent long distance bike packer and cycling powerhouse, this ultralight multi-sport hydration pack was developed with one mission; to go to the ends of the earth faster, further, and lighter; all while staying organized with the essentials and hydrated with the included 2L hydration bladder. Increase the carry functionality by taking advantage of compatibility with our Zerk 3L Loki Lumbar pack which acts as a chest rig on the Zerk 13 shoulder straps!

Utilizing High Tenacity ROBIC Nylon with super durable Ultra High Molecular Weight Polyethylene (UHMWPE) ripstop, the Zerk 13 liter pack will be your best friend and greatest asset for whenever your adventures find you on two wheels or two feet.

FEATURES

  • Large main compartment panel loader holds up to 13 liters of gear with internal organization sleeves
  • 2.0 L TSI™ water bladder included (BPA, PVC & Phthalate-Free) with backpanel hose port and magnetic hose clasp
  • Extra wide, Airflow EVA padded shoulder straps with dual adjustable sternum straps
  • 4 Large mesh front pockets on shoulder straps; accommodates 500ml bottles & cellphones
  • 1.5” padded waistbelt with dual zippered stash pockets
  • Reflective zipper pullers for extra visibility
  • Reflective bike light clip-in point (Bike Light Not Included)
  • Two reflective lash points
  • Semi-rigid interior frame foam pad (EVA / Atilon foam)
  • Large side water bottle pockets with angled opening to easily remove and insert items while on the go
  • Front panel mesh pocket for hauling additional quick access gear
  • Dual vertical daisy chains on front panel with single tool loop
  • Front zippered vertical stash pocket
  • Additional front panel bungee attachment system included (Some Assembly Required)
  • Bright yellow interior panel for maximum visibility

MATERIALS

  • 100d ROBIC™ Nylon X-Grid Ripstop (UHMPE) w/ UTS Coating*
  • 210d ROBIC™ Nylon X-Grid Ripstop (UHMPE) w/ UTS Coating*
  • 150d HD Poly WBC Liner*
  • 840d x 100d stretch mesh
  • *There are no intentionally added PFAS in this item

CALIFORNIA WARNING: Cancer and Reproductive Harm | www.P65Warnings.ca.gov

DIMENSIONS

  • 9" x 18" x 5" (L x H x D)

VOLUME

  • 793 in3 / 13 L

CAPACITY

  • Waistbelt Range: 28" - 48"
  • Torso Range: 15" - 19"
  • Weight Load: Suggested up to 15 lbs

WEIGHT

  • 1 lb 13 oz

Customer Reviews

Based on 4 reviews
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A
Ashley
I really needed an instruction manual

I'm not a biker but I was searching high and low for a daypack to take on my upcoming group tour of Vietnam. I was struggling to find the right volume of pack. They all seemed either too big (18L) or too small (10L). I had never heard of Mountainsmith. I found my bag brand new with tags still attached at a resale store for about half price. I'm not planning to use the hydration bladder on this trip so I was searching for a tall and kind of narrow front netted pocket for holding my 40 oz Hydroflask during our daily activities. Our tour operator provides us with regular access to filtered water to fill water bottles. In my experience, water bottles always are tipping out of side pockets on backpacks! This one is so perfect and I can support it a bit with the exterior cord. The front chest pockets are amazing and a unique feature for a backpack. I can fit my iPhone 17 Pro Max + case in one and might put some bathroom supplies in the other (tissue, wipes) for easy access. I wanted my phone to be safe from phone snatchers (so not constantly in my hand or hanging out of my pants pocket), but also at the ready, as I take a lot of photos. Those three pockets are what immediately sold me. It took a lot of wrangling, rethinking, and adjusting but I think I finally got this pack to fit correctly on my petite but curvy frame. This backpack is also big enough to take on the plane as my carry on, since I'll be checking my main suitcase. I did a trial packing run and fit a change of clothes/ underwear/ socks/ pajamas in a compression packing cube. I'll be able to fit my device chargers and essential medications and toothbrush as well. Once I'm reunited with my suitcase, I'll keep all that stuff in the suitcase and use the day pack for a sun shirt, hat, sunblock, mosquito spray, water bottle, phone, etc. I wish I could find a really good overview video of the backpack and all its features/ functions/ adjustments (something more detailed than this one) because I’m probably missing something. It would be helpful to see the backpack on a woman’s body, as we are built differently!

K
Kim G
Finally found a replacement for my 15 year old pack!

So many pockets! The pack is very comfortable to ride and hike with. I’m not a fan of hip belts when riding, but this one works great; it positions the pack weight where it needs to be. I forget I’m wearing it. Each element of the pack was very well thought out.

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Erin-Grace
room and accessibilty for ALL of your on board burritos (and water)

amazing room for multiple burritos and the correct amount of water to be lugging on your back while pushing pedals around the map. love the securness (its a word now) of the three clip straps, the depth of the shoulder strap pockets going vertically down the torso and how handy the flank pockets are at the bottom of the shoulder straps. The magnet to hold the water hose is a complete game changer. no more fighting with the ridiculous clip that played a part in my last wreck. I cannot recommend this backpack enough for getting out there!!!

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Phillip
Most comfortable backpack

Most comfortable backpack for all rides!