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Mountain Bike Hydration Backpack ST 900 12L 2L Water - Black

Sale price: $99.99 Regular price:

The 12 litre capacity is well-distributed for bringing what you need. Enjoy the mesh at the back and various adjustments.

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Sale price: $99.99 Regular price:

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San Francisco, 735 Market St. Options

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About this item:

  • Capacity: 6 L bag with a 2 L bladder for hydration
  • Multiple compartments: Many compartments for tool and item storage
  • Stability: Adjustable straps
  • Carrying comfort: Mesh straps and foam padding for excellent comfort
  • Use: For hiking, camping, and other outdoor activities
Model: 8300158

Product Features

Mountain Bike Hydration Backpack ST 900 12L 2L Water - Black | This hydration backpack is designed to keep you easily hydrated when mountain bike touring for less than 4 hours.

The 12 litre capacity is well-distributed for bringing what you need. Enjoy the mesh at the back and various adjustments.

A photo of the Mountain Bike Hydration Backpack ST 900 12L 2L Water - Black in use
A photo of the Mountain Bike Hydration Backpack ST 900 12L 2L Water - Black in use


A usable volume of 12L and a 2L water bladder: drinking for up to 4 hours.

Multiple compartments

1 large compartment, 1 tool pocket, 2 side pockets, 1 helmet gusset, etc.


Adjusts with the shoulder straps, the waist strap, and the chest strap.

Carrying comfort

There are 3D mesh pads at the back and hips for ventilation.


The bag comes with a built-in protective rain and mud cover.


VIOO CLIP light attachment point on the back

Questions & Answers

Product Customer Reviews

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very nice bag…

very pleasant bag to carry once the straps are adjusted it is well stuck to the back and does not move you don't have the impression of having it

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Nice product

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Very convenient

Very practical and well-designed backpack, pleasant to carry. Correct capacity. Rain protection incorporated with storage at the bottom.

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The best choice at this price.

Comfortable, functional. Great compartments, roomy, roomy - perfect for an all-day trip from spring to autumn. I would buy again.

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Perfect for roller skates

I bought it with the intention of using it for roller skating. It can accommodate protectors, a glasses case and a sweatshirt. I have a long way to go to the path, so I attach my helmet and roller skates to my backpack using the silver handles. Shoes go into the backpack while riding. The backpack is light and airy, does not restrict movement, holds well and does not disturb balance, so it is also perfect for driving around the city, where we need maneuverability. I wasn't convinced about the built-in water bag because I'm a bit disgusted by them, but I changed my mind. The bag can be easily washed because it opens completely and is closed with a plastic zipper. Cool idea with a built-in rain cover. To be improved: The middle pocket should have a double zipper. The pockets on the hip belts should be larger, because it is impossible to put a phone in them.


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The backpack is just the right size, quality workmanship. Hydrovac met expectations. Satisfaction.

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Rockrider water tank backpack

comfortable, good choice for the price

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Excellent backpack designed for mountain biking. Sufficient space, numerous compartments and always stable in every situation. Robust material and possibility of storing any helmet, even the full-face one. Excellent value for money.

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given to a friend...

given to a friend for her birthday, I dream of having the same one!

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Fits well and ventilates well.

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Nice backpack

only the main compartment and the front compartment are strangely partially connected. I don't quite understand. Good protection for the back even in the event of a fall (tried it myself) ;-)

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Additional Product Information


Bag: 50.0% Polyester, 50.0% Polyamide ; Water pouch: 100.0% Thermoplastic Polyurethane

Maintenance tips:

For hygiene reasons, we recommend cleaning your water bladder after each use. To help you clean out the tube, you can order a special brush using product ref. 5935596. This kit comes with a hanger to make it easier to dry out the inside of the bladder.Tip: If you don't want your drink to taste like plastic, wash the bladder, dry it well, and place it in your freezer. Take it out a few hours before your ride. This will stop any flavour transfer.

Bring with you...

This hydration pack comes with a 2 L water bladder. But also remember to bring:- your food (granola bars, energy gels, etc.)- your multi-function adjustment tool (ref: 8386669)- a puncture repair kit (inner tube, tyre lever, hand pump, puncture repair spray, CO² cartridge, etc.)- your chain rivet extractor and a quick link - a piece of identification, blood type card- a means of payment and a telephone- a 1st aid kit- etc...

A large water bladder

With its 2-litre capacity, your water bladder will last you around 3 hours of riding. Its wide opening makes it quick to fill up. When closing it, make sure the slider clips into place to ensure it won't leak.

Great water flow

Before you set off, remember to remove the air to improve water flow. Just turn the hydration bladder upside down once filled, direct the air bubbles towards the tube opening and suck them out. The bite valve is lockable (rotates 180°) to prevent leaks when not in use. It won't drip, even when in the open position. To get a good flow when drinking, pinch the valve with your mouth and suck.

Care tips

To make your bag last longer, we recommend waterproofing it before you first use it. Even though the fabric is already water-repellent, extra waterproofing will stop mud getting caked onto it. Before each ride, remember to wash and dry your water bladder with the help of the cleaning kit (product ref. 5935596).If you don't want to get a plasticky taste, put your dry water bladder in your freezer. This will stop any flavour transfer.

Extending the product's lifespan

Remember to take a look at our water bladders support page to help your product last longer.

Product testing

At Decathlon, all of our products are tested by a panel of users in the conditions for which the products were designed. These tests are led and monitored by our design team. All of these tests allow our product managers, engineers and the whole mountain biking team to develop, create and design technical products that guarantee customer satisfaction.

Storage instructions

Once clean and dry, keep your backpack and water bladder in a dry place and away from direct sources of heat. Clean by hand in soapy water.




Size Guide Visual

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