The difference between internal frame and external frame backpacks
Tags: backpack | external frame | internal frame
Backpackers have two options when choosing a backpack frame: "external" or "internal". Those words describe the major differences between these two categories of backpacks: internal frames have the frame (or frame sheet) on the inside while external frames have the frame on the outside. Simple as that.
BACKGROUND
Back in the day, external frames were the only option. Limited by available materials and early technology, the only way backpack manufacturers were able to create backpacks with large capacities was to create an equally large frame to hold the weight and to distribute it properly over your body.
As technology evolved and newer materials were developed, manufactures found ways to shift from a tube frame to a flexible plastic sheet frame that could slide inside the backpack. The result was a frame that could hold similar amounts of weight in a less bulky package. Internal frame backs were lighter, better fitting, and provided more mobility to the user.
Consequently, internal frame packs have largely replaced their larger external frame cousins. Yet, externals still have their time and place. Die-hards who started backpacking before there were internal frame packs, people who carry very heavy loads, and youngsters getting started in the pursuit are all good candidates for an external-framed backpack. SUMMARY OF BENEFITS OF EACH FRAME TYPE
The benefits of an external-frame pack are:
- you can carry heavy loads more easily with an external frame pack
- packing is easier in external frame packs as they are more forgiving and can carry awkward loads more easily
- external-framed backpacks tend to last longer
- external-framed backpacks are less expensive than most similarly sized internal-framed backpacks
- they don't alter backpacker's center of balance
- they don't have trail clearance issues as they sit low and close to the backpaker's body
- they lighter weight
- they provide more flexibility and versatility
- there is a huge variety of sizes and styles
- they are highly adjustable
CHOOSING A BACKPACK
Now that you have an idea of what the differences are between the two types of backpack frames, here are some tips on how to choose the specific pack that is right for you.
GENDER
Backpacks are not unisex anymore. It used to be that women had to choose a smaller backpack, since all packs were designed using generalities about male anatomy. No longer. Manufacturers now make "women-specific" packs that recognize that women tend to have shorter torsos than men and need features like shoulder straps hitting their chest in different areas than men do. So, start by narrowing the options based on your gender.
Be aware, however, that your women-specific external-frame options will be much more limited than your internal-frame options. There are just way more internal-frame backpacks being made right now. In addition, if you have a particularly small torso, an external-frame pack, even a small or women-specific model, might not be your best bet. There is a minimum amount of frame needed to support a women-specific external-frame pack and that limitation puts the packs out of consideration for some smaller women (unless you are willing to accept other, less women-friendly, features of smaller men's or boy's packs such as hip belt and shoulder strap placement).
Nutshell: smaller backpackers should look towards internal-frame packs.
CAPACITY
You have a lot of options when choosing backpack size. You will first want to narrow down the available options by size or capacity, which is measured in cubic inches and is described by the duration of hiking in which you typically partake. Backpacks are generally classified as daypacks (2,000 to 2,500 cubic inch capacity), weekend packs (2,500 to 3,500 cubic inch capacity), weeklong packs (3,500 to 5,000 cubic inch capacity), and expedition packs (5,000 cubic inch and above capacity). There will be several choices of internal-frame backpacks in each of these categories.
Unlike internals, external-framed backpacks are designed to carry heavy loads. As a consequence, you will only find backpacks in the upper end of the capacity range, say from 3,500 cubic inches (a weekend pack) to 5,000 cubic inches and above (weeklong to expedition packs). If you plan on taking extended trips or carry lots of gear (like if you are taking kids with you and might have to carry some of their gear), go larger. If your backpacking is going to be mostly 2-3 day stretches, consider the smaller end of the spectrum.
Nutshell: Unless you are looking for a large pack, look to internals. If you need lots of capacity, you will find good options in both external and internal packs, but externals excel with heavier weights.
TORSO SIZE
Torso size, the distance between the base of your neck and the small of your back, is the critical measurement in choosing an external frame backpack. You will want a pack that, when fully loaded, fits your torso so that the waistbelt or hipbelt sits comfortably on your hips and where the shoulder straps (at the connection of the strap to your backpack) sits about two inches below the top of your shoulder blade.
Internal frame packs are relatively easy to adjust. Typically, there will be belt and Velcro mechanisms that allow you to slide the frame and/or hip belt up or down. External frame backpacks can be adjusted with tools provided with the pack. Nevertheless, if you have a short torso, an external pack might not be the best choice for you. Internal packs are made that fit a much wider range of sizes and are more easily adjusted.
A good outdoor store can help you make these adjustments. In fact, a good store will have you try on the packs, load them with sufficient weight to determine fit, and show you how to adjust the backpack.
Nutshell: both frame types can be adjusted, but internal frame backpacks are easier and have more flexibility.
FEATURES
Once you whittle you selection down by gender, capacity, and torso size, you will only have far fewer packs to choose from. Still, you want to make sure your backpack has some, if not all, of the following features:
- hydration sleeve and ports
- sternum strap
- adjustable suspension
- multiple side pockets
- separate sleeping bag compartment
- multiple access to main compartments
Another nice feature is a pack that has a removable top compartment that allows you to leave the main pack at base camp and take the smaller compartment on day trips or side hikes as a modified lumbar pack. Many internal frames have this option. Most external frames don't.
Also, don't forget a raincover for your pack. You don't want your gear getting soaked, if the weather turns south.
I hope this article has proved a useful starting point. Now get out there and select that pack!
Author: Joseph Hazelbaker
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