I need a pack for the Pacific Crest Trail. What is the best frameless backpack with a hip belt for heavy water carries?

Carrying heavy water loads (6 lbs to 12 lbs extra for stretches like the Southern California desert or the Oregon/California border) with a completely frameless backpack that features a true load-bearing hip belt is a bit of a physics contradiction.

Without a frame or rigid stays, a hip belt cannot effectively transfer heavy shoulder weight down to your hips; it mostly just keeps the pack from bouncing around your waist. However, if your base weight is dialed in (< 10 lbs) and you want a frameless or minimally structured pack with a supportive belt to stabilize large water volumes, here are the top options that handle the strain best:

• LiteAF Dyneema 40L / 46L Curve Frameless
  • Why it works: LiteAF builds custom ultralight packs with an optional, fully padded 4-inch-wide hip belt made of spacer mesh and foam. While still frameless, the wrap of their custom belt is wider and more structured than standard webbing, providing exceptional stability when your side pockets are loaded down with dual 1-liter Smartwater bottles plus a couple of extra liter backups.
  • Check it out: Build your own on the LiteAF Custom Backpack Page.[1]
• Gossamer Gear Kumo 36 (with Fast Belt)
  • Why it works: The Kumo is a legendary minimalist frameless pack. It doesn't have a rigid internal frame, but it features a integrated sitpad pocket that acts as a light back panel buffer. You can pair it with their Gossamer Gear Fast Belt to add stability. It won't transfer 30 lbs of water weight to your hips like a framed pack, but it hugs the torso cleanly and handles temporary heavy loads better than most frameless sacks.
• Zpacks Nero Classic 40L (with Padded Hip Belt or Webbing Belt)
  • Why it works: Made from ultra-durable Ultra 100X fabric , the Nero is a streamlined, completely frameless roll-top pack . Zpacks offers an optional snap-on padded belt or standard webbing belt. It is designed for a sub-10-lb base weight, but the fabric has zero stretch or sag, meaning a heavy water load won't warp the pack's structure out from under you.
  • Check it out: View specs on the Zpacks Nero Classic Product Page.[1]
• A note of caution on heavy water carries: If you expect to routinely shoulder 15 lb of water + food + gear (pushing total pack weight past 28–30 lbs), even the best frameless pack will cause shoulder fatigue. Many PCT hikers pivot to a lightly framed pack with a real hip belt—like the Durston Kakwa 40 or Hyperlite Unbound 40 —which weighs barely over 2 lbs but uses a frame or stays to actually shift that brutal desert water weight onto your hips.

Are you planning to go strictly frameless to keep your base weight under 10 lbs, or would you be open to a featherweight framed pack (around 28 oz) that can comfortably handle a 40-lb water-and-food load without bruising your shoulders?

Carrying heavy water loads (4 to 6+ liters, or 9 to 13+ lbs of water alone) on a truly frameless backpack pushes the physics of ultralight backpacking to its absolute limit. Without a frame sheet or stays to transfer weight to your hips, a heavy water carry will cause a frameless pack to "barrel" (push into your spine) and sag off your shoulders, rendering even a good hip belt mostly decorative for weight transfer.

However, if your base weight is dialed in (< 10 lbs) and you specifically want a frameless pack with a functional, structured hip belt that handles temporary heavy water capacity better than the competition, specific cottage-industry choices stand out:

Add to list LiteAF builds exceptional custom packs out of composite materials. Crucially, their optional fully padded, interchangeable hip belts (3'' to 4'' wide) are structurally superior to the flimsy webbing or thin foam wings found on most frameless bags. While it is still frameless, adding their structured hip belt and load lifter options helps cinch the high-capacity volume closer to your body during desert or dry-stretch water tanking.[1]

Add to list A legendary PCT thru-hiking pack. It features a unique stashable structural hip belt rather than a heavily plush one. It doesn’t transfer heavy loads like a framed pack, but the bottom stash pocket allows you to tuck in loose gear or food, keeping the main cavity optimized for awkward bulk. It's meant for sub-25 lb total loads ideally, but experienced hikers push it when necessary.[1]

Add to list A minimalist frameless pack that features a surprisingly robust, wide-winged removable hip belt for a pack of its class. It relies on a removable sit-light pad for back panel structure. It won't comfortably haul 35 lbs all day, but for a short 4-liter push, the hip belt integration stops the pack from bouncing wildly.

A Crucial Reality Check for the PCT

If you anticipate frequent, multi-liter water carries (common in the Southern California desert or parts of Oregon/Washington), strongly consider a framed ultralight pack with a pivoting hip belt —such as the Gossamer Gear Mariposa 60 or Hyperlite Mountain Gear Unbound 40 . They weigh barely over 2 lbs, but the internal frame structure ensures that when you load 12 lbs of water into/onto them, the weight actually rests on your hips instead of bruising your traps.[1]

To help narrow this down:

• What is your estimated base weight?
• Which section of the PCT are you starting with (e.g., Campo/SoCal desert)?
• Do you prefer a roll-top or draw-string closure?

If heavy water carries are the priority, I’d be careful about going truly frameless. On the PCT, 5–7 L of water adds 11–15.4 lb by itself, and a frameless pack’s hip belt can stabilize that weight but can’t transfer it as effectively as a frame.

My picks

1. Best true frameless: Outdoor Vitals CS40 Ultra

• CS40 Ultra Backpack - $344.97 (OutdoorVitals)

This is the one I’d choose if you insist on frameless. It was specifically designed around the problem of carrying heavier loads in a frameless pack, and it has a substantially more supportive suspension/hip-belt setup than minimalist frameless packs.Parse

2. Best proven PCT alternative: ULA UltraGrid CDT

A very compelling choice if you want a traditional thru-hiking pack with a real padded hip belt while remaining genuinely frameless. It weighs about 27 oz and has 50 L of capacity, but I'd keep the total loaded weight around 25 lb or less.SectionHiker.com

3. If "frameless-ish" is acceptable: Gossamer Gear Mariposa 60

This is actually what I'd recommend for a PCT hiker expecting frequent big water carries. It's technically framed, but the removable/lightweight suspension is close in spirit to an ultralight frameless pack while giving you much better load transfer. Independent testing calls it one of the best ultralight packs overall, including for heavier loads.GearLab

The important cutoff

I'd use roughly this rule:

• ≤20–22 lb loaded: almost any good frameless pack
• 22–25 lb: CS40 / CDT territory
• 25–30 lb: I'd strongly favor the Mariposa or another lightweight framed pack
• 30+ lb: don't buy a frameless pack just to save a few ounces

For context, current PCT gear data shows the ULA Circuit, Durston Kakwa, and Gossamer Gear Mariposa among the prominent PCT packs, while the Circuit is rated for considerably more load than a typical frameless pack.Halfway Anywhere

If your base weight is ~10–12 lb and your maximum water carry is 6 L, I'd personally take a lightweight framed pack rather than a true frameless one. The extra few ounces are very worthwhile when you're starting a dry stretch with ~25–30 lb on your back.

If you give me your base weight + maximum water carry (e.g. 12 lb + 6 L) + whether you'll carry a bear can, I can narrow this to the best 2–3 packs for your exact PCT load.

This is actually what I'd recommend for a PCT hiker expecting frequent big water carries. It's technically framed, but the removable/lightweight suspension is close in spirit to an ultralight frameless pack while giving you much better load transfer. Independent testing calls it one of the best ultralight packs overall, including for heavier loads.

The important cutoff

For the Pacific Crest Trail, a frameless pack with a real hip belt is a bit of a niche choice because the PCT has some of the biggest water carries in the U.S. (especially the Southern California desert). A frameless pack’s hip belt can stabilize the load, but it generally won’t transfer weight to your hips like a framed pack will. Frameless packs shine when your base weight is low and your total pack weight stays roughly in the low 20s.Outdoor Life+1

If you specifically want frameless + hip belt + occasional heavy water carries, these are the ones I’d look at:

🥇 Best overall: Nashville Pack Cutaway 40

Best for: A dialed-in PCT thru-hiker carrying ~20–25 lb total loads

• Weight: about 1 lb range depending on options
• Excellent shoulder strap pockets and exterior access
• Optional padded hip belt makes it one of the better frameless load haulers
• Carries very well for a true frameless pack
• Great match for a 10–12 lb base weight PCT kit

The downside: once you’re carrying 30+ lb after a huge water carry, the lack of a frame becomes noticeable.Parse+1

🥈 Best for durability + bigger water carries: Outdoor Vitals CS40 Ultra

Best for: PCT hikers who expect some rough desert sections and want more structure

• More supportive than many ultralight frameless designs
• Good volume for PCT food carries
• Designed specifically around the problem of carrying remote water loads

It is still frameless, so I would not choose it if you regularly expect 30–35 lb loads.

🥉 Best classic PCT-style option: ULA Equipment UltraGrid CDT

Best for: A larger-volume frameless pack with a traditional thru-hiking feel

• 50L capacity
• Padded hip belt options
• Durable construction
• More forgiving than many minimalist frameless packsULA Equipment

The tradeoff is weight: it’s not the absolute lightest frameless option.

Also worth considering

• Mountain Smith Zerk 40 — one of the more comfortable frameless packs thanks to its harness and structure, but shoulder load increases as weight climbs.CleverHiker
• Pa'lante Packs V2 — a favorite among experienced ultralighters, but better for very low base weights.SectionHiker.com

My pick depends on your expected desert load:

• Base weight under 10 lb, water carries up to ~5 L: Nashville Cutaway 40
• Base weight 10–12 lb, water carries 5–7 L: Outdoor Vitals CS40 Ultra or ULA CDT
• Frequently carrying 8+ L water (17.6+ lb of water): I would seriously consider a lightweight framed pack instead. A pack like the Hyperlite Mountain Gear Unbound 40 or similar framed ultralight pack will likely feel better when leaving the Sierra and crossing dry sections.CleverHiker+1

For a PCT-specific recommendation, tell me:

1. Your base weight (without food/water),
2. Your largest expected water carry (liters or miles between sources), and
3. Your height/torso length.

That will narrow it down a lot.

Carrying heavy water loads (4 to 6 liters, or ~ $9-$13 lbs of water alone) on a truly frameless backpack pushes the physics of ultralight backpacking to the absolute limit. Without a frame sheet or stays, weight transfer to a hip belt only works effectively if the pack has exceptional stability, side compression to lock down water bottles, and ideally structural features like load lifters or a vest-style harness to keep the load from pulling backward off your back.

Top options balancing a frameless structure, a supportive hip belt, and the capacity to handle bulky/heavy water carries include:

This custom ultralight pack features an optional fully padded 4-inch removable hip belt and rare-for-frameless load lifters . Its adjustable dual-side pockets are specifically designed to securely accommodate up to two 1L Smartwater bottles per side (4L total exterior), and the load lifters help pull the upper water/gear weight tight against your torso. Available on the LiteAF Ultra 40L Curve Frameless Page.[1]liteaf.com

A hybrid design blending a running-vest shoulder structure with a traditional pack body, it comes with a removable padded hip belt and 3/4-inch load lifters. The oversized side pockets can each swallow up to two 1.5L bottles (6L capacity total outside), and the built-in shoulder/vest foam yoke helps distribute heavy, shifting liquid weight across a wider upper-body footprint. Check details on the Exotic Packs Brazos 45L Frameless Page.[1]

While its removable "FastBelt" isn't strictly designed for heavy load-transfer (the weight rides primarily on your shoulders/vest harness), the pack integrates a removable SitLight pad in the back panel which provides structural stiffness against "barreling" when you stuff the main compartment. Its side pockets can hold ample water, though it relies more on a stable, hug-like vest fit than a heavy-duty hip belt. View it at Gossamer Gear.

Note: If your total starting weight (base weight + food + max water) exceeds 25-$30 lbs—which is common on PCT stretches like the Southern California desert or the Alkali-heavy sections—even the best frameless packs will cause shoulder fatigue. Many thru-hikers opt for a framed ultralight alternative (like the *Gossamer Gear Mariposa 60 * or *Hyperlite Mountain Gear Unbound 40 * ) for the comfort margin during 6-liter carries.

To help narrow this down, let me know:

• What is your estimated base weight?
• What is the maximum water capacity you anticipate needing to carry at one time?

I can help you decide if a frameless setup will safely support your specific gear list.