Tuesday, July 3, 2018

How to fit a backpack

For the past 12 years I have been employed by a major outdoor retailer, and a big part of what I do is training new staff. One of my specialties is training staff in backpack fitting. I have trained welll over one hundred people and I estimate that I have done between eight and twelve thousand backpack fittings. I think it is one of the most important things I do. If your backpack isn't comfortable you won't be having a good time in the backcountry.

The first thing you have to understand is that backpacks are a lot like shoes. They may look good on the wall, and they may be your buddies favorite. But until you actually try them on and see how they feel you can't tell if they are right for you. People come in all shapes and sizes, and backpack fitting is about how it feels, and how the backpack carries a load. If it doesn't feel good on your back, and doesn't efficiently transfer the weight of the load onto your hips, it doesn't matter how many awards the backpack has won.

Next, you have to understand that backpacks have two sizes. A volume - expressed in cubic liters - and a size as it relates to its wearer, small, medium or large. The volume size of your pack is going to depend on the size of the gear you are putting in it, and is dictated by what we call the 'big three.' The big three is your sleeping bag, pad and tent. (some people say the big three is backpack, sleep system and tent, but for our purposes the backpack size is going to be determined by the other parts of the equation. So I don't include it in the big three.)

If you're an older back packer, like myself, your brain may prefer to work in cubic inches. You can turn cubic liters to cubic inches by multiplying by 64. a 50 liter pack (multiply 50 by 64) is a 3200 cubic inch pack.

Traditionally, backpackers will buy a backpack and then fill it with gear. The big three and the other gear needed. But I think this is backwards. If the volume of your backpack is going to be determined by the things going into it, why buy the backpack first? You risk having a backpack that is either too large (you will end up carrying more gear than needed, which means more weight than needed) or too small (you won't be able to carry all that is needed.) So what I generally suggest is that people buy their big three first, and then their backpack. The size and weight of the big three will largely be dictated by price. As you spend more money, your gear will weigh less and pack smaller. The depressing phrase we use in the industry is, the more you pay, the less you get.

When I started working in this field - over a decade ago - we regularly sold backpacks that ranged from 65 liters to 85 liters, this was the normal range. We stocked packs as large as 105 liters and could get packs as big as 115 liters. Today, after a decade of advancement in materials and design the bulk of the packs I sell are 45 to 65 liters. We still have packs - a few - that range up to 85 liters but I no longer have immediate access to packs bigger than that. The bulk of the AT thru hikers I fit for packs are buying packs in the 50 to 65 liter range. I also see people who started the AT with larger packs and by the time they get to me they are shopping again but this time for a smaller pack.

So you have a pack in mind you would like to try, in an appropriate volume, but how do you know what size (small, medium or large) you actually need. Well, to use the shoe analogy again, you need to get your torso measured, just like you would get your feet measured before buying shoes (you do get your feet measured, right?!) A torso measurement is best accomplished with a tool designed for the purpose. Because you are measuring from your iliac crest, on the side of your body, to C7, the large bump on the back of your neck.

It is almost impossible to measure yourself and difficult to measure someone else using just a tape measure. Any reputable backpacking store should have a measuring device to use for a torso measurement - they are provided by the backpack manufacturers at no cost. If your retailer doesn't have one, you need to find a new shop to frequent. The torso measurement spans from 16 inches to 21 inches. 16 and 17 are "small" 18 and 19 are "Medium" and 20 and 21 are "large." These measurements are not gender specific. Your torso measurement is also not correlated to height. You can be 6'4" and be a medium (with long legs) or 5'8" and be a large. Most men, about 80% are mediums. 15% precent of men are Larges, with the remainder being smalls. Most women (about 80% as well) are smalls, with 15% being extra small and 5% being medium.

Time to try on a pack in both the size that suits our torso and the volume that will work with our gear. Don't ever try on a pack empty. Let me repeat that. DON'T EVER TRY ON A PACK THAT IS EMPTY! It is a complete waste of time. Every pack feels good empty. To try on a pack the retailer you are visiting should have both pillows and sandbags to load a pack with weight. When I see a person take a pack of the wall, without checking its size, and then putting it on without weight, or making any adjustment to the pack I know immediately the level of knowledge of the person trying on the pack.

To be a knowledgable customer, come into your outfitter and say "I am shopping for a pack in 50 to 65 liter range and I am a medium, measuring 18 inches." If you don't know your size, say "I need a pack, and I need my torso measured."

When I do a pack fitting I generally open the divider between sleeping bag compartment and main compartment and the put two large pillows in the pack (I find it easier to stuff the pack from the top than to put one in the bottom and one in the top.) Then on top of the pillows I put a ten pound sand bag. This should be right behind the shoulder blades of the pack wearer, close to their center of gravity. (incidentally, this is mimicking the way you should pack your backpack for a trip. Heavy stuff right behind your shoulder blades, light stuff - like your sleeping bag at the very bottom) I then close the pack and tighten all the compression straps snugly. Then, before allowing the wearer to put on the pack, I loosen all the straps. This forces you - the wearer - to tighten the straps for themselves instead of just buckling them and going, which prevents them from just assuming they are set correctly. After loosening all the straps I confirm that the wearer knows where their iliac crest is - the top of the hip bone on their side - and I tell them that the iliac crest should be in the middle of the hip belt on the pack. I have them put on the pack, and get the hip belt in the correct location, and t then have them tighten it. We are then going to work our way up the pack tightening straps. Shoulder straps are next, The sternum strap is optional, and I tighten the load lifter straps above the wearers shoulders.

A lot of people want more weight in the pack when they are trying it on. Some pack fitters I know use 15 pounds, I generally use 10. Here is the thing. We are using a sandbag. Dead weight. Yes I can put 30 pounds of sand in your pack so you can see what it feels like, but it isn't going to feel like a real load. Gear just feels different. But 10 pounds is enough weight to that if there is a fit problem, I will be able to see it, and the wearer will be able to feel it. If they still want 30 pounds of dead weight, I will add it after an initial fitting.

Shoulder straps should be snug, but not tight. The sternum strap pulls the shoulder straps towards the center of the body, and it keeps them from rolling off the outside of the shoulders. It is optional, most people like it, but it makes me feel like I can't breath. Load lifter straps are the straps that get people in trouble.

Load Lifters go from the top of the shoulder strap to the top portion of the pack bag itself, usually connecting to the frame. When someone first puts on the pack I make them just snug. There used to be a rule that load lifters had to be at a 45 degree angle, but this is no longer true. With some packs they go straight back, and frequently with the current line of Osprey packs they may angle up at more than 45 degrees. The tighter you pull the load lifters the more it pulls the top of the pack towards your center of gravity - which feels good. The pack feels like it is part of you. But, the tighter those straps are, the more weight is shifted from your hips to the front of your shoulders, which will quickly fatigue your shoulders. This is the strap that you want to be adjusting throughout the day. If the terrain is flat, leave them looser, and allow the weight of the pack to be on your hips. If the terrain is steep, and you are using your hands for balance it is time to tighten them up. When you are walking, if you feel the pack wobble back and forth, they need to be a little tighter.

When someone comes to me and says "this pack hurts me when I wear it" the first thing I check is the load lifters, and 90% of the time they are too tight. Because it feels good when you pull them tighter, people do it all day, until they are completely tight, and their shoulders are exhausted. We want 50 to 60% of the packs weight on our hips.

Once the wearer has the pack on and straps are adjusted I check three things. I physically confirm - by sticking a finger into the space between waist belt and wearer - that their iliac crest is below the top of the waist belt. You have to physically touch the persons hip bone. Another good indicator of waist belt position is the location of the buckle. It should be over, or at least close to the belly button. Next, can I slide my fingers under the the shoulder strap with only a little resistance? Too much resistance means there is too much weight on the wearers shoulders, no resistance means the pack is probably too high. This is almost impossible to do on yourself. Find someone to do it for you. Finally, I check the location of the buckle that tightens the shoulder strap. It should be closer to the waist belt than the arm pit. This is a general indicator of pack size versus wearer size. If it is all the way down at the waist belt (meaning the shoulder strap is as tight as it can get, or close to it) it is an indicator that the pack might be too big. If it is up near the arm pit there is a chance it will rub the wearer while they are walking! - This is an indicator that the pack is too small.

Then you should take a walk in this pack for at least ten minutes. Is anything rubbing? pinching? binding? if it is doing it a little now, how will it feel after ten miles? Perhaps this isn't the pack for you.

Some packs offer adjustability in the back panel itself. I generally only have to adjust this if your size is on the border between medium and large or small and medium. Likewise, some packs have removable shoulder straps and waist belts. You generally only have to swap out sizes if your waist size and torso size is greatly different, or if you have particularly broad shoulders.

I generally discourage people from trying on more than three packs in a day. I find the memories of what was good and what wasn't gets muddy. If you don't have a definitive answer after three packs, take a photo of the tag of the pack that felt the best and come back in a couple of days and try it again, and then continue trying on other packs to compare to your previous best. Keep notes on what you tried, and what felt good and what didn't. Also, when going to try on a pack, dress like you are going hiking. I have had people come in for fittings who are dressed inappropriately, and let's just say it is awkward for everyone.

Here are the bullet points:

• Get measured
• Try on a pack with weight in it
• Check (or have checked) three land marks (hip bone, shoulder, and shoulder strap buckle)

Do everything you can - without sacrificing safety - to keep your pack weight low. We used to use the range of a quarter to a third of your body weight, is an effective load for you to carry. Today, using modern gear this is way to high of a number. In general, for most weekend backpackers, your pack weight should be between 23 to 35 pounds. I did 3 days on the AT last year, and my pack weight was 32 pounds with real food (not much lighter freeze dried) and a heavyish stove - an msr whisperlite.

Finding the right pack fit takes some time, and patience. But I have yet to find someone that can't get a good, comfortable fit out of a backpack. It is about finding something that fits your shape. Let me know if anything needs clarification.

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