Gregory is best known as a backpacking brand, and to be honest, I wasn’t that familiar with the line previous to receiving the Endo 15 to test. However, it’s clear that when they decided to enter the MTB market they were going to do it right, as the Gregory Endo 15 hydration pack is loaded with features.
Not that it’s overwhelming, as some feature-rich designs can be. You can simply throw it on and go for a ride; it’s a backpack that holds water. That said, after digging in, it is clear the team of Gregory have put some serious thought into designing a pack for the needs of mountain bikers.. and more.

The sternum strap features a magnetic fastener for one handed use; it also integrates with the bite valve of the hydration reservoir. We initially weren’t sure what this elastic loop did — it’s the eyewear strap. Clever.
Features & Specs
- 15 liter gear capacity
- 2.03 lb weight
- Spring steel internal frame
- Includes hydration reservoir
- Adjustable hip belt system
- Magnetic sternum strap
- Removable zipper tool pouch included
- Dual hip belt pockets
- Safety light lash
- Webbing keepers
- Stretch mesh stuff pocket
- Sunglass quick stow system on shoulder harness

The outer gear pocket has key fob, two mesh organizer pockets and a padded sunglass or device pocket.
The stand out feature of the Endo pack is an adjustable hip belt, which can be shifted up or down to move the weight of the pack up or down to stabilize the load. It also allow users of different heights to tailor the fit to the most comfortable location and customize the fit. It makes up the Gregory RS Suspension System which uses a spring steel internal frame to suspend the pack off your back and allows airflow. It has a low profile, so while there is a pocket of air, the profile of the pack is still fairly low and keeps the weight close to your center of mass.

The adjustable Ride Stability system works to keep the load stable and aids in dialing in the pack fit.
Other details include dual hip belt pockets for quick access to food or your main tool, a lined and padded pocket for sunglasses or phone and a removable tool pouch. The pack includes a hydration reservoir that features an integrated drying hanger and is structured to keep things stable.

Cinch straps help compress the load and add to the stability of the pack, and can be use for a helmet carry.
Like a lot of helmets, there’s an outside pocket for gear overflow. Deeper and more usable than most, it holds soft pads, goggles or a jacket easily thanks to the stretch mesh. The zippers all use zipper pulls that are easy to grab on to, even wearing gloves.
On the bike
Many of the features of the pack were designed to provide stability and it results in a pack that carries the load on the trail extremely well. When you have a full bladder, spare clothing and gear loaded, you’re going to feel the weight on your back. However, it carries so well that it doesn’t hamper the riding experience. As the user, you still need to pack the weight strategically to maximize this benefit, but I had no problem playing around on the trail, or jibbing around while waiting for the group to regroup. On a fast paced 17 mile XC ride in Oakridge, I didn’t have any complaints whatsoever.
I prefer waist packs for a lot of the session style-trail riding near Portland; however having a good pack to carry additional hydration on epic rides is a necessity. The Endo stands out in a sea of viable options. Packing smart and keeping the weight as low as possible definitely plays a part in maintaining the fun factor, but at 2.03 lbs, the pack doesn’t contribute much to that weight.
The one downside to the Endo is it isn’t water resistant, so if you ride in inclement weather you’ll want to add a rain cover, or a small dry bag you can carry inside. Adding water resistance materials or a rain fly to the pack would add weight but as I wear a pack when I leave the house daily — and carry a good amount of stuff as part of my EDC — I’d love to try a variation on the pack that could handle the rigors of my daily commute. I’ve forgotten you can still get rowdy on a bike while carrying gear on your back.
Final thoughts
I’ve put the Endo to use commuting, hiking and guiding/coaching. When riding, I prefer to go with a minimal load as possible to keep the weight down. Wearing a pack riding does provide a bit of insurance in terms of spine protection thanks to the water bladder, but it also can hamper maneuverability on jumpy, berm-filled flow trail riding. This was never an issue with the Endo, and it’s since become my go-to hydration pack for days I need maximum storage capacity.
The suspended back panel removes the bulk of my complaints of a backpack, which is back sweat. The Endo performs fantastically in this regard. The other, is pack sway, or how much it swings back and forth during quick weight shifts in corners, or whipping around in the air. The pack is structured well and exceeds expectations, thanks to the low profile and rigidity.
The Gregory Endo 15 lists for $130. Learn more at Gregorypacks.com
Want one? You can support the site by buying it on Amazon.com here.