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Backpacks

Panel loader

Also called clamshell, front-loading pack

What is a panel loader?

A panel loader opens with a zip that runs around the front of the pack, so the whole compartment folds open like a suitcase. The alternative is a top loader, which you access through an opening at the top.

Panel loader at a glance

Opens
Three sides, like a suitcase
Weight cost
The zip
Common on
Travel and day packs

The problem with a top loader

A top loader is a bucket. Whatever went in first is at the bottom, and reaching it means taking everything else out, which is fine on a backpacking trip where you unpack at camp anyway and maddening on a day hike where you want the sandwich you packed at 6am.

How a panel loader differs

A panel loader unzips around three sides and lays open flat. Everything is visible at once, nothing has to be excavated, and packing is more like packing a suitcase than filling a sack. Almost every day pack under 35 liters works this way, and it's the right choice at that size.

Why the zip is the catch

The zip is the catch. It's the heaviest single component on the pack, it's the most likely thing to fail, and a long zip is a long line for water to find its way through. That's why bigger backpacking packs still tend towards top loading with a drawcord and a lid, and why hybrid designs that add a side or bottom zip to a top loader have become common.

What this means when you're choosing

  • Zip quality and size, since this is the component that fails first
  • Whether a top loader has a secondary zip for reaching the bottom
  • Storm flaps over the zip line if you hike anywhere wet

Panel loader vs Top loader

Panel loaderTop loader
Reaching thingsEverything at once, like a suitcaseWhatever is on top, and unpack for the rest
WeightHeavier, because of the zipLighter, a drawcord and a lid
Failure modeThe zip, which usually ends the tripA drawcord, which you can field-repair
OverfillingStrains the zipExtension collar takes the extra

Which to pick: Panel for travel and day use where access matters. Top loading for multi-day backpacking, where weight and a failure you can fix in the field matter more.

The common mistake

Overfilling one

A stuffed panel loader puts the whole load onto a zip that was never a structural component. Zips fail under lateral strain, usually at the worst moment, and a blown main zip ends a trip in a way a torn drawcord does not.

Common questions

Which is better, panel loading or top loading?

Panel loading for day hikes, top loading for multi-day carries. The dividing line is roughly whether you're going into the pack repeatedly through the day or unpacking it once at camp.

Are panel loaders less waterproof?

Slightly, yes. A zip is a seam and water finds seams, so a long front zip is more vulnerable than a rolled or drawcorded top. A pack liner solves it either way and weighs almost nothing.

Where this comes up

Guides on Tom's Hiking where panel loader changes which product is right for you.

More in backpacks

Load lifters

Load lifters are the short straps running from the top of the shoulder harness back to the top of the pack frame. They pull the load in towards your body so it stops levering you backwards. They don't carry weight themselves.

Hipbelt

The hipbelt is the padded belt that wraps your pelvis and transfers pack weight onto your hips instead of your shoulders. On a loaded backpacking pack it should be carrying most of the weight, often quoted as 70 to 80 percent.

Framesheet

A framesheet is a sheet of stiff plastic in a pack's backpanel that spreads the load across your back and stops contents from poking through. It's lighter than a frame but gives you less vertical support.

Internal frame

An internal frame is the structure hidden inside a pack's backpanel, usually one or two aluminum stays or a perimeter hoop, that carries weight from the shoulders down to the hipbelt. It's what makes a pack load-bearing.

Suspended mesh backpanel

A suspended mesh backpanel stretches a taut mesh across a curved frame so the pack body sits away from your back with an air gap behind it. It's the coolest-running backpanel design and the one that holds the load furthest from your spine.

Pack lid

The lid, or brain, is the padded flap that covers the top of a top-loading pack, usually carrying one or two zipped pockets. A floating lid is one attached by adjustable straps so it can rise as the pack is overfilled.

Extension collar

An extension collar is the fabric tube above a top-loading pack's main compartment, closed by a drawcord. Rolled down it does nothing; pulled up it adds capacity, typically 5 to 10 liters beyond the pack's quoted volume.

Shove-it pocket

A shove-it pocket is the open-topped stretch panel across the front of a pack. It has no zip, so you can push a wet jacket or a map into it one-handed while walking, and pull it out just as fast.

Load rating

A load rating is the weight a pack maker says a pack carries well, usually given as a range in pounds. It describes the frame and hipbelt rather than the fabric, so exceeding it doesn't break the pack, it just moves the weight to your shoulders.

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