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Osprey’s Viper 9 is designed for cyclists who like to push the limits—packing full day rides into half that time and bringing just enough gear to make it home.

Whatever you choose to carry, the foam framesheet spreads your load across a ventilated mesh backpanel for all-day comfort. The BioStretch shoulder harness provides a contoured fit and the webbing hipbelt is removable to shave ounces. If you end up carrying extra weight, top compression straps lend extra load stability.

Access your gear in the main compartment via the zippered front panel. You can slip small items into the dual side mesh or harness pockets or stash a layer in the front fabric shove-it pocket for quick access. There’s even a scratch-free slash pocket for your shades.

Bike-friendly features include a Hydraulics® LT 2.5 liter reservoir with magnetic bite valve retention, internal bike pump storage loops, and Osprey’s innovative LidLock helmet attachment system.

Key Attributes


A dedicated hydration compartment with direct zip access for easy loading includes a Hydraulics™ LT 2.5 liter reservoir with magnetic sternum strap bite valve attachment.

LidLock Helmet Attachment System

When you’re at the brewpub celebrating a great ride, the LidLock system connects your helmet to the pack so you can retain possession of both after a couple of lagers.


Ultralight with minimal body contact for a fit that feels like it’s not there.


  • Upper Side Compression Straps - Dual upper side compression straps help stabilize the load
  • Front Shove-It Pocket - Front panel shove-it pocket with zippered organization pocket helps gear accessible and systematized
  • LidLock Helmet Attachment - An elasticized LidLock helmet attachment system provides storage for your helmet
  • Blinker Light Attachment - The blinker light attachment strap found near the base of the front panel of the pack allows for quick light attachment for high visibility in the dark
  • Hydration Compartment - Hydration sleeve with direct access zip offers fast loading. Hydraulics® 2.5L LT reservoir included
  • Harness Pocket - Stretch mesh harness pocket provides easy access to energy snacks and other quickly needed items
  • Front Stash Pocket - Front zippered stash pocket with heat embossed scratch-free lining safely holds sunglasses or phone

Carry Information

Atilon foam framesheet

  • Atilon foam framesheet allows dynamic body movement while it spreads load across the entire back panel

Airscape Backpanel

  • Mesh covered ridged foam allows maximum ventilation while keeping the load close to the body

Biostretch Harness

  • Mesh covered die cut foam provides an active and contouring fit and ventilation

Webbing Hipbelt

  • Removable 20mm webbing ride stabilizing hipbelt


  Volume Dimensions Weight
O/S 549 in3 / 9 l 18h x 9w x 7d in. 1.21 lbs.
O/S 549 in3 / 9 l 45h x 22w x 18d cm 0.55 kg
210D Poly Honey Comb
420HD Packcloth
420HD Packcloth
Product Manual Additional languages available here »
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Near perfect pack, completely perfect warranty


The Viper 9 is just the right size and format for mountain biking, for me anyway. It holds what it needs to hold and can take more in the area between the main compartment and outer pocket if you need to drag rain gear along. The water bladder was big for a smallish pack. That's important for those of us who ride the Southwest in summer. But, the pack could only put up with so much abuse. After 4 years of bashing and crashing and sewing-up damage, I sent it to Osprey for a little professional attention. They must have had a good laugh when they saw it, because they decided to just send me a new one. OK, that's a Mother of a warranty. I would not expect that from any business. The pack didn't fail; it died a gallant death in the face of hostile forces. Let's see, who am I going to for my next pack?

New Mexico


Great pack but bladder was a huge disappointment


This is my first Osprey pack, and while I am very happy with the pack itself (features, construction, design), the changes that were made to the normal Hydrapak bladder baffle me. The internal ribs, hard plastic hose guide and smaller than usual top opening all combine to make it nearly impossible to turn the bladder inside out - Hydrapak's primary selling point and the main reason I abandoned Camelbak. The internal ribs make for difficult cleaning. There's already a clip/loop to hang the bladder inside the pack, so I don't know why the hard plastic hose guide plate was added. I would have given this pack a glowing review if it had just shipped with a normal 2.5L Hydrapak reservoir with Osprey silkscreened onto it, but instead I'm getting rid of the supplied bladder (want it back?) and will purchase a Hydrapak bladder... which doesn't come in 2.5L so I have to either downsize to a 2 or try to cram in a 3... Grrr.

Newark, DE


Compact, lightweight but holds everything you need and more!


The Viper 9 is a superb biking pack! This thing holds everything I need for quick bike ride after work or an all day adventure in the mountains. It's able to hold all of my bike supplies like extra tubes, small co2 pump, extra co2 cartridges, tire levers and tools. Plenty of room for snacks and other gear too. The hydration reservoir never feels bulky on my back and the magnetic clip on the bite valve is super convenient. The stash pocket on the front is great for stuffing in a jacket if the weather is questionable. I've used this pack for casual cruises and aggressive downhill rides at the resort. It's never let me down and I often forget I'm even wearing it!




4.3 3


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