EXTERNAL VERSUS INTERNAL FRAME

While internal-frame packs are the current pack of choice with A.T. long-distance hikers, each pack style has pros and cons to consider. Here are the basic differences between the two: the external frame is designed to distribute weight equally and has a high center of gravity (perfect for established trails), while the internal-frame pack is designed to ease off-trail travel and has a lower center of gravity (popular for off-trail hiking and mountaineering).

In terms of keeping cool, external frames are superior. They also have more pockets in which to stow and organize items. The packs don’t sag, and they are built to carry heavier loads more comfortably. Externals also tend to be less expensive than internals. On the other hand, internals provide better balance and pass through rocks, trees, and underbrush easier because they have fewer outside bulges and pockets.

HIP BELTS

One common, and critical, area the two packs styles have in common is the hip belt. The hip belt carries the bulk of the weight, so that a properly fitted pack allows you to drop one shoulder out of its strap without a significant change in weight distribution. The hip belt should be padded, well built, and snug-fitting. Many companies offer optional hip belts that are larger or smaller than the standard adjustable hip belt. If you’re planning a long-distance hike, remember that weight loss may cause the hip belt that fit you when you began to not fit you later in your trip.

Hip belts are also prone to breaking because of the amount of stress they receive. Because the internal frame’s hip belt is usually an integral part of the pack, the entire pack often needs to be returned to fix it, though some pack manufacturers are beginning to make interchangeable parts for internal-frame packs. If a hip belt breaks on externals, you can usually remove the hip belts for repair. Manufacturers are usually great about replacing them free of charge. Keep the manufacturer’s telephone number handy in case you need to order another hip belt or have one replaced.

Here are some more things to think about when considering a pack.

EXTERNAL FRAME

External-frame packs come in top-loading, front-loading, and combination models. A top-loading pack works like a duffle bag attached to a frame, whereas front-loading packs give you easy access to your gear. Most manufacturers design their external packs with both a top-loaded and front-loaded section as well as front and side pockets.

Manufacturers of external-frame packs boast that the frame keeps the pack away from your body and thus is cooler in the summer. A good external-frame pack will have a mesh backband that will allow for circulation of air. This band should be tight and adjusted for your comfort.

Features to look for in an external-frame pack include:

• A welded tubular frame, preferably of a lightweight and strong material such as aluminum or molded plastic
• A coated nylon pack cloth (although not waterproof, it is water resistant—a pack cover is needed to waterproof your pack)
• Thick, padded shoulder straps
• A mesh backband to allow air to circulate between your back and the pack
• A thick, foam hipbelt with an easy-release buckle
• Outside pockets on the pack bag

TIPS FOR FITTING AN EXTERNAL FRAME

• When fitting your pack make sure that the shoulder straps are level with or an inch or two above the shoulders.
• The mesh backband should fit snugly, but comfortably, against your back, and the hip belt should ride on your pelvis.
• Adjust the hip belt up or down along the frame to prevent the lower end of the frame from making contact with your lower back.
• Shoulder straps should not pinch your neck nor should they slide off your shoulders. Mounted too high, they put too much weight on your shoulders; too low, on your hips.
• If the pack comes with load-lifters, they should join the frame at ear level and attach to the shoulder straps over your collarbone. Weight can be distributed from shoulders to hips with these straps.
• A sternum strap will help hold the pack more closely to your back.
• Accessory features in packs include ice-axe loops, crampon patches, ski holders, accessory pockets, and camera rings. On some packs you will find that these features are standard rather than optional.

External frame (JanSport Carson)

INTERNAL FRAME

Victoria had an agonizing time climbing through Maine’s Mahoosuc Notch with her external-frame pack. The 0.9-mile stretch requires squeezing in and out, over and under endless tumbled boulders. Her external frame continually threw her off-balance, leaving her quaking in her boots and near tears. And every time she fell, she banged her head on the frame. At that moment, she would have done anything for an internal frame. Internal frames are designed to alleviate the problems Victoria had in Maine. Because they hug your body and have a lower center of gravity (internal-frame packs are equipped with harnesses, straps, and other adjustments so that the pack may be form-fitted to each wearer), they enhance balance and allow more upper-body mobility and flexibility.

Most internal-frame packs are top-loading—the pack has a big top opening into which you dump what will fit, pack it down, and load some more. Okay, you’re not really supposed to do it that way. For a top-loading pack, you need to be very organized. That way, not only do you know where all your stuff is, exactly, but you can also more evenly distribute the weight. Many top-loaders have extension tubes (basically a collar that extends up) to provide additional volume with a floating lid to cover it all. With no zippers or a zipper only around the sleeping bag compartment, internal-frame packs are more water-resistant than externals.

Internal frame (Gregory Palisade)

However, there are more options out there. Panel-loading internal frame packs have one or more zippers on the front so you don’t have to dig through all your stuff to get at whatever is on the bottom of the pack. Having more zippers, though, can make the pack harder to load due to the strain you create on zippers by overstuffing. Zippers also decrease a pack’s overall resistance to water. If you do go for a panel-loader, make sure the zippers are really tough and there are at least one or two compression straps over the zippers to relieve some of the pressure (not to mention to hold things together should a zipper burst).

Hybrid-loading packs offer the best of both worlds because you can load from the top but you can also unzip to remove something near the bottom without unpacking everything. Once again, though, make sure the zippers are tough and that there is compression-strap backup.

There are two basic designs that make up the internal frame—parallel or X-shaped, depending on how the aluminum bars are sewn inside the packbag. These bars are custom bent to fit the curve of your back, then slid back into place. The internal frame is then fitted to your body by a number of straps attached to the packbag.

Things to look for in an internal frame include:

• Contoured aluminum stays to help distribute weight to your hips
• Thick, padded shoulder straps and hip belt
• A lumbar pad that will help support a heavy load and enhance ventilation
• Compression straps to keep smaller loads from shifting
• A reinforced bottom to resist abrasion
• A lot of lash points and loops to carry gear outside the pack
• A slim profile with either outside or add-on pockets
• Cinch straps at the shoulder and waist to keep the load close to your back

TIPS FOR FITTING AN INTERNAL FRAME

• Once the hip belt is fastened, make sure that the pack’s stays protrude two to four inches above your shoulders. If the stays are outside this range, look for a pack that has a longer or shorter torso, respectively.
• If the padded ends of the hip belt overlap in front, the belt is too big. If they rub your belly, you’ll need a larger belt.
• The pack fits you in the shoulders if the shoulder straps join the pack about two inches below the tops of your shoulders. The lower ends of the straps should be a hand’s width below your armpits.
• Load-lifter straps should join your frame at ear level to comfortably divert pressure to the front of your shoulders. The buckles for these straps should be positioned over your collarbone. Weight can be distributed from waist to shoulders with these straps, and you should vary the position as you hike for the most comfort.
• If the pack hugs your back like a child holding on for a piggyback ride, you have a proper fit.
• If the waist belt is distorted by the way you cinched your stabilizing belts, the pack needs readjustment. Always make sure the pack is cinched tightly.