The ULA UltraGrid CDT is a 50L frameless backpack designed for ultralight backpacking, long day hikes, or travel, with a maximum recommended load of 25 pounds. Weighing 27.1 oz (768 g), the CDT is a streamlined backpack with 29.1 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 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.

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• Total Volume: 3051 cu in /50 liters (29.1L closed storage 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 – it’s a frameless backpack
• Fabric: UltraGrid body, UltraMesh front pocket, Robic nylon hipbelt and pockets
• Torso Lengths: 15-18″, 18-21″, 21-24″, 24″+
• Hip Belt Sizing: 26-30″, 30-34″, 34-38″, 38-42″, 42-47″, 47+”
• Gender: J or S-shaped shoulder straps available.
• For complete specs, visit Ultralight Equipment’s UltraGrid CDT Product Page

UltraGrid: What it is and what it isn’t

UltraGrid is a fabric made from recycled nylon interwoven with Ultra-High-Molecular-Weight-Polyethylene (UHMWPE) fibers, which makes it exceptionally tear-resistant. It outperforms 210D ripstop nylon in durability and is nearly as strong as the Ultra 200X used on ultralight backpacks, yet is much more affordable and more flexible. It also has a 1500mm PU backing and a PFC-free C0 DWR coating for moisture protection, which makes it highly water resistant. In other words, it improves on the nylon ripstop used by backpack manufacturers in the past, but it is still nylon and doesn’t have the wow factor that backpacks made with Ultra100x, Ultra 200x, or Dyneema DCF, or Woven Dyneema have. And while not as “ultralight” as those materials, you’ll still be hard-pressed to destroy it.

Backpack Organization and Storage

The CDT has a pleated UltraMesh front stretch pocket for added durability.

The 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, the way a true roll top should be, to provide proper top compression, but can also be clipped 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 sewn-in Y-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 for hanging 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 UltraGrid CDT also has a sewn-on Y-strap for securing items to the top of the pack

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. ULA claims the side pockets can hold two bottles, but they don’t specify what kind of bottles. I assume these are Smartwater bottles, because two Nalgenes or two Aquafina bottles don’t fit.

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 for storing longer items lashed to the sides of the pack with a compression strap, such as a fishing rod or a trekking umbrella.

The side bottle pockets are reachable when wearing the pack

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 opening the pack’s main compartment. It’s made with UltraMesh, a woven blend of nylon 6-6, Lycra, and Ultra-PE that is very tear-resistant and breathable, so contents will eventually dry. 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 hipbelt pockets are large but made of less durable nylon

Finally, there are two zippered pockets on the exterior of the hip belt, large enough to store a smartphone, snacks, AquaMira bottles, bug dope, and such. The fronts of both pockets are hard-faced to prevent tearing, and the pockets feature heavy-duty zippers for durability. The pockets are made of Robic Nylon, not UltraGrid, so they are less durable and less water-resistant.

Backpack Frame and Suspension

Foam back panel

The CDT is a frameless backpack that takes a little practice to pack, as it has 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. I like to replace it with several sections of a folding foam pad, like a Therm-a-Rest Zlite or a NEMO Switchback, which is thicker and stiffer, making 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.

The best way to pack the CDT after that is to line the pack with a Nylofume pack liner or trash compactor bag, then pack the rest of your gear into it by stuffing it loosely, without using many stuff sacks to organize it. The reason this takes some practice is that the CDT will barrel uncomfortably into your back if you stuff it too tightly. Still, 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. It’s almost like your gear “becomes the frame.”

New hipbelt

The new CDT hipbelt is replaceable and attached to the pack with velcro.

ULA dropped the sewn-on hipbelt used on this pack in previous versions and switched to a new replaceable one. They probably did this to reduce the time it takes to sew on a custom length for each new customer and to reduce the inventory that resellers have to keep on hand, so they can just slot in the hipbelt size required for each purchase.

The hipbelt is attached to the back of the pack using Velcro. Like ULAs’ other packs, there is extra length in the velcro attachment so you can move the hipbelt up or down a few inches to lengthen or shorten the torso. While useful, torso length is a lot less important on a frameless backpack with a 25 lb max recommended load (the same as a daypack), you’re not relying on load transfer to the hipbelt. You can also remove the hipbelt to save weight, or order the pack without one if you prefer.

The previous version of the CDT had a sewn-on hip belt.

The new hipbelt also has the two-tier adjustment system that ULA uses on their other hipbelts, which lets you adjust the tension on the top of the hipbelt separately from the bottom to accommodate different hipbelt shapes. The new hipbelt is much more contoured (note the curve above) and therefore better suited to female hips. This is also different from the ULA packs I’ve reviewed previously (I’ve reviewed multiple generations of the entire ULA product line, through three different company owners, over the past 15 years).

However, the lumbar pad at the rear of the hipbelt, which wasn’t there before, means the back of the pack is no longer flush with your back. While this increases air flow back there, the pack body moves around a bit more when you walk. It’s hard to notice when the pack is more heavily laden, and the contents at the bottom of the pack bag are fairly stiff (watch for barrelling, though.) You probably wouldn’t notice the difference, unless you own an older version of the pack. Despite the more “dynamic” feel, I think the new hipbelt is a net positive change if you plan to actually backpack with this pack.

S-shaped shoulder straps are available

The CDT is available with J-shaped straps, which are better suited to people with flat, level shoulders, or more female-friendly S-shaped shoulder straps, which are better suited to people with sloping shoulders and rounded chests. Contrarian as I am, I prefer S-shaped straps even though I have flat shoulders because they let me position the sternum strap lower on my chest.

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 them; they’re pointless without one, since you’re just pulling at the pack fabric, which is loose or stretches. They’re also less important on a pack designed for carrying lighter loads.

External Attachment and Compression System

The CDT has only one tier of side compression straps above the side water bottle pockets. This makes it difficult to attach long or 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 use these straps to secure long skinny objects to the side of the pack, like a Tenkara fishing rod case, and even then, I have to check often that it hasn’t fallen off.

The single-sided compression strap is useful for holding a water bottle and filter in place.

If you like to keep a water filter attached to a plastic bottle, which can make it top-heavy, that single compression strap is also the best way to prevent it from falling out of the side bottle pocket. Of course, if it’s snugged up under the single compression strap, you won’t be able to reach back and pull it out of the pocket.

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 with cord and cord locks.

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

• There is a 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 daisy-chain slots on the front of the shoulder straps for hanging a satellite messenger, accessory pockets, or water bottle sleeves.

Comparable frameless ultralight backpacking packs

Recommendation

The ULA UltraGird CDT is a frameless ultralight backpack 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 50 liters (29.1 liters of closed storage), making it ideal for backpacking trips with very lightweight gear that you can pack loosely in the main compartment. The CDT also makes a good day pack for extended hikes or technical use, and it’s good for travel since it’s frameless and easy to get through security or fit in overhead airplane bins. If you want a pack like the UltraGrid CDT but with more capacity and better external attachment options, I highly recommend checking out the ULA UltraGrid Ohm 63L, which has a very lightweight hoop frame and is similar to the UltraGrid CDT.

See Also:

• • ULA Ultra 24 Circuit 68L Backpack Review
  • ULA Ultra Circuit SV 48L Backpack Review
  • ULA Ohm 63 Backpack Review
  • ULA Photon Backpack Review

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Disclosure: ULA loaned the author a pack for review.