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ULA CDT 54L Backpack Review

ULA CDT Backpack Review

The ULA CDT is a 54L frameless backpack designed for ultralight backpacking, long day hikes, or travel that has a maximum recommended load of 25 pounds. Weighing 27.1 oz (768 g), the CDT is a streamlined backpack with 36 liters of closed storage in the main pack bag and extension collar, with the remainder distributed across its open pockets and hip belt storage. While the CDT is not the lightest frameless backpack available today, it is one of the largest in terms of overall volume, it is available with J-shaped or female-friendly S-shaped shoulder straps, and comes in a very wide range of torso sizes and hip belt lengths. ULA also offers a huge number of customization options on the CDT from colors and fabrics to frame and hip belt components, so you can personalize the CDT for your needs.

Specs at a Glance

  • Total Volume: 3370 cu in /54 liters (36 liters in the main bag+extension collar)
  • Weight: 27.1 oz (768 g) – size medium
  • Rec’d Max Load: 25 lbs
  • Rec’d Base Weight: 12 lbs or less
  • Pockets: 5 plus main
  • Hydration compatible: Yes
  • Load lifters: No
  • Fabric: 400d Robic nylon (XPac, 420 Nylon, and Cordura available as custom options)
  • Torso Lengths: 15-18″, 18-21″, 21-24″, 24″+
  • Hip Belt Sizing: <30″, 30-36″, 36″+
  • Gender: Men’s and Women’s-specific shoulder straps available.
  • For complete specs, visit Ultralight Equipment’s CDT Product Page

Backpack Organization and Storage

The CDT is a roll top style pack with a long front mesh pocket
The CDT is a roll-top-style pack with a long front mesh pocket.

The ULA CDT is an ultralight style backpack with a large main compartment, a front stretch mesh pocket, roomy side water bottle pockets, and zippered pockets on the hip belt. It has a roll-top closure that is secured with side webbing straps or can be buckled closed on top. The roll top itself doesn’t have a stiffener, snaps, or velcro to hold the sides closed when rolling it up but there is a webbing strap that loops over the top to secure and compress the contents.

The CDT is hydration compatible with side hydration ports and two webbing loops inside where you can hang a hydration pocket (sold separately). There aren’t hose keeper loops on the shoulder straps, however, so it can be a little awkward to manage a hose.

The pack’s side water bottle pockets are solid fabric to protect them from abrasion and tearing. They’re large enough to fit a 1 liter Nalgene or soda bottle with room to spare; it’s also easy to pull out a bottle while walking and replace it without stopping to take off the pack. Both water bottle pockets have drains at their base and an elastic cord on top that can be cinched closed and secured with a cord lock to keep items from shifting or dropping out. The elastic cord is also handy when storing longer items that are also lashed to the sides of the pack with a compression strap, like a fishing rod or trekking umbrella.

There is an elastic cord at the top of the side pockets.
There is an elastic cord at the top of the side pockets.

The front of each side pocket has a small hole you can stick your hand into although that’s not the intention; it’s part of the shoulder strap suspension system which terminates at the base of each pocket. While this attachment point helps pull the pack closer to your back, small items can fall out of the side water bottle pockets and the side pockets shouldn’t be used for that type of storage.

Like many ultralight style packs, the CDT has a long front mesh pocket that’s ideal for storing wet gear or layers you want fast access to during the day without having to open up the pack’s main compartment. I typically store snacks, my rain gear, a water filter, and an empty wet reservoir in the mesh pocket to keep them away from my dry clothing inside the main compartment. The stretch mesh has a very tight weave and excellent durability for on-trail use, but I wouldn’t recommend taking the CDT on rugged bushwhacking trips if you want to keep the fabric intact.

Finally, there are two zippered pockets on the exterior of the hip belt, large enough to store a smartphone, a point-and-shoot camera, snacks, AquaMira bottles, bug dope, and such. The fronts of both pockets are hard-faced to prevent tearing with heavy-duty zippers for durability.

The hip belt pockets can hold a Smartphone, camera or snacks.
The hip belt pockets can hold a Smartphone or camera and snacks.

Backpack Frame and Suspension

The CDT is a frameless backpack that takes a little practice to pack because it has so little structure. There is a foam pad held in place in the main compartment by two elastic straps behind the shoulder straps. While it protects your back from being poked by sharp objects, it’s very soft and doesn’t provide any structure or load transfer to your hips. Many people remove and replace it with several sections of a folding foam pad, like a Therm-a-Rest Zlite or a NEMO Switchback that is thicker, stiffer, and makes the pack easier to load. You don’t want to use the entire folding pad, because it will eat up too much space, just 4 to 6 side-by-side sections.

I like to replace the foam pad (left) with 4 panels of a Therm-a-Rest Zlite foam pad (right.)
I like to replace the foam pad (left) with 4 panels of a Therm-a-Rest Zlite foam pad (right.) They fit inside perfectly.

The best way to pack the CDT after that is to line the pack with a trash compactor bag and pack the rest of your gear into it by stuffing it loose, without using a lot of stuff sacks to organize it. The reason this takes some practice is that the CDT will barrel uncomfortably if you stuff it too tightly, although you don’t want the contents to be too loose because the pack carries more comfortably when the gear fills out all the empty spaces in the pack bag. It’s almost like your gear “becomes the frame.”

The hip belt is sewn directly onto the pack.
The hip belt is sewn directly onto the pack.

While it doesn’t have a direct connection to the hip belt, the downward force of the load is flush with your back and does drive some of the weight into the hip belt. The majority of the weight will still ride on your shoulders, which is why you want to keep the total weight of the contents below 25 lbs and preferably even less.

The CDT hip belt can be adjusted to fit the shape of your hips.
The CDT hip belt can be adjusted to fit the shape of your hips.

If you’re familiar with the wide hip belt that ULA uses on their Catalyst, Circuit, and Ohm backpacks, the CDT hip belt is narrower and as befits a pack that carries lighter maximum loads. It’s also sewn directly to the back of the backpack instead of being replaceable so it’s closer to your back and hips.

ULA CDT 54L Backpack


High Volume Frameless Pack

The CDT is an ultralight frameless backpack that can carry up to 25 lbs of gear comfortably. Frameless packs with this much capacity are fairly rare. That, plus the gender specific options available with the CDT make it a very desirable option.

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The CDT hipbelt has two tiers of webbing straps that connect with a center buckle, so it can mold around the angle of your hips to a certain degree. I like the pass-thru style hip belt on ULA’s larger backpacks much better because it’s wider and more robust although that matters less on the CDT because it’s not intended to carry heavy loads.

The CDT is available with S-shaped shoulder straps.
The CDT is available with S-shaped shoulder straps.

The CDT is available with J-shaped or female-friendly S-shaped shoulder straps that are better for people with sloping shoulders and rounded chests. Men can use S-shaped straps too and I find them to be a lot more comfortable along the sides of my torso. One thing worth noting about the shoulder straps is that there are no load lifters on them since you really need a frame to anchor load lifters (they’re pointless without one). They’re also less important on a pack designed for carrying lighter loads with a hip belt that is set flush to your back.

External Attachment and Compression System

The CDT only has one tier of side compression straps located above the side water bottle pockets. This makes it difficult to attach bulky gear to the outside of the pack because there’s only one strap to hold it on with. Yanking on that single compression strap also doesn’t compress the pack bag much because the surrounding fabric is too soft to transmit the force very far. I only use these straps to secure long skinny objects to the side of the pack like a Tenkara fishing rod case.

The CDT only has one tier of side compression straps above the side pockets.
The CDT only has one tier of side compression straps above the side pockets.

The only other compression on the pack is provided by the top strap and the roll top, from the top down. There aren’t any other convenient anchor points or webbing loops along the pack seams to create your own attachment points using cord and with some cord locks.

That said, you can attach additional gear to the outside of the pack in a few places.

  • There are pair of trekking pole straps and ice axe loops at the top and bottom of the front mesh pocket to secure poles or an axe.
  • In addition, there are plastic rings, webbing, and daisy chain slots on the front of the shoulder straps to hang a satellite messenger, accessory pockets, or water bottle sleeves.

Pack Customizations

ULA offers an unprecedented number of customization options on the ULA CDT beyond the myriad color and fabric options they offer. For example, you can add a hoop frame to the CDT with load lifters or a pass-thru hip belt, like the ones on ULA’s larger packs. You can also add bottom straps to hold a sleeping pad or top straps to carry large objects on top of the roll top. These customizations add up pretty quickly, but you can turn the CDT into more of a “framed” backpack if you like, although it would be less expensive just to buy a ULA Ohm which is the next step up anyway.


The ULA CDT is a frameless ultralight backpack that’s designed for carrying 10-12 pound base loads with a maximum of 25 pounds, including food, fuel, and water. Weighing 27.1 oz (768 g) it has a capacity of 54 liters (36 liters of closed storage) making it ideal for backpacking trips where you have very lightweight but “puffy” gear that you can pack loose inside the main compartment. The CDT also makes an excellent day pack and is also good for travel since it’s frameless and easy to get through security or stuff in overhead airplane bins.

While the CDT is not the lightest frameless backpack available, its high volume is pretty attractive because it makes it easier to pack, especially with “puffy” gear, in addition to the flexibility of shrinking it down when less capacity is required. When you add in the option for S-shaped shoulder straps and all the custom options that ULA offers, the CDT becomes an attractive option if gear weight is less of a priority than fit, volume, or color and fabric customization.

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Disclosure: ULA loaned the author a backpack for this review. 

One comment

  1. Nice color. :-)

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