How to choose the right-sized Pack

September 26, 2022

BCA ambassador Mike Duffy wears a pack over 150 days a year. Snowmobiling, backpacking, skiing, snowboarding, biking, and motorcycling. He definitely does not want 150 days of discomfort. Read his tips for choosing the right pack size and fit.

The right size pack and fit makes for comfort and less fatigue whether you are snowmobiling, backpacking, skiing, snowboarding, or biking. BCA ambassador Mike Duffy's packs fit great and are comfortable. It’s easy to get it right and he explains how below.

How to choose the right-sized Float airbag pack:

BCA offers a wide variety of volume and torso length options.  Size is defined in two ways. Storage volume and the torso length it was designed for. The number on the outside of the pack refers to the storage volume. The Float 40 is designed for a bigger person and features a longer pack (torso), a larger waist belt, and longer shoulder straps. At the smallest size of the line, the Float 12 is made for the shortest torso.

For snowmobiling, I feel lighter and less volume is better. I rarely use a pack bigger than 25 liters, unless I’m on a rescue or have to carry extra gear. Why? That extra weight will wear you down over the course of a day. Bigger people can usually handle larger capacity packs.

Volume: The volume corresponding to the pack number is in liters and lets you know the volume the pack will hold. How much do you really want to carry and what is appropriate for your size? Give someone a 40-liter pack and they’ll fill it. I prefer 22 liters or less. Pack smart, put nonessentials and redundant items in a tunnel bag. Less weight on your back = less fatigue and more maneuverability.

Torso length: Refers to the length of the pack and should fit your torso length for the correct and most comfortable fit. Your height doesn’t necessarily determine the torso length of the pack. A tall person can have a short torso, and a short person can have a long torso. Many packs are designed for a universal fit, one size fits all, which is a compromise if you’re not in the size range the pack was designed for. Get a pack that fits you and you’ll be much happier comfort-wise. Don’t want the pack hitting your helmet or hanging down by your tail bone. Some packs have an adjustable torso length and some manufacturers have different packs for different sized torso’s.

How to measure your torso: Find the top of your hip bone on the side of your body. This is called the iliac crest. Measure from the base of your neck (C7) to the iliac crest, this is your torso length.

How does your torso length correspond to pack size? In backpacking, they size packs according to torso lengths. You measure your torso, and the pack manufacturer’s size chart tells you what size is best for you. In snowmobiling, we’re not that sophisticated. You have to try them on. Needless to say, one size does not fit all.

Try on the pack, then look to see how the pack fits you after you adjust it.

Adjusting the pack: You want the pack to feel like an extension of your body. You don’t want it loose and bouncing around, which will definitely accelerate fatigue. I see so many riders with the waist belt loose, which can really cause problems with neck and back pain.

1st step: Loosen all the straps. Put some weight in the pack. 10 -15 lbs.

Waist belt: The majority of the weight should ride on your hips (80% hips, 20% shoulders), not your shoulders. This is accomplished by having the waist belt snug. The waist belt is positioned so the middle of the belt is positioned at the top of the iliac crest.

Having a loose waist belt allows the pack to bounce around. The bouncing weight fatigues your back and neck. With packs, no adjustment should feel binding.

NO: Pack is too short. This photo depicts a waist belt that is above the hips. All the weight is being carried with the shoulders. The rider is 6’3”.

Shoulder straps: Make so the pack isn’t hanging back and is comfortable. You do not want the shoulder straps to restrict movement.

Sternum Strap: This adjustment is different than backpacking when using an airbag pack. Position the sternum strap low on the chest. Why? When the airbag inflates, the bag will want to lift you up. The sternum strap wants to be away from the neck and the leg strap snug, so you don’t get choked.

Leg strap: Don’t forget the leg strap on an avalanche airbag pack. It keeps the pack from lifting off your body or the sternum strap from rising up to the neck.

NO: Example of shoulder straps not wrapping over shoulders.

YES: Correct example of shoulder straps wrapping over shoulders and waist belt on hips.

Note: The shoulder straps should wrap over the top of your shoulders. They should not go from the shoulder at an upward angle to the shoulder strap anchor point. If the shoulder strap is not wrapping over your shoulder, then the torso length of the pack is most likely too long. Many BCA packs have a vertically adjustable waist belt to adjust the torso length.

Visual inspection: You have the pack on and have adjusted it. What should you look for?

You’ll want a friend to help or have a mirror to eye the fit. Here’s how to adjust:

  • The top of the pack shouldn’t be high up on the neck in the back. Put a helmet on and tilt your head back as if you were looking up at a climb. The helmet shouldn’t hit the pack.
  • Likewise, the pack shouldn’t be hanging down by your tail bone or hanging down on your butt.
  • Shoulder straps wrap around the shoulder? The shoulder strap anchor point should be 1’-2” below the top of the shoulder.
  • Adjust the waist belt up and down. Try on different torso length packs.

What to look for in pack design

  • Low profile, close to your back. Don’t want the pack extending too far out from the body. Farther the weight is from the body, the more swing weight you have. Wears you down faster when riding aggressively. You have to stop that weight from “swinging” by tightening muscles, which leads to fatigue.
  • Internal pockets. The more the better. You can separate out essential gear. Better than the black hole that you have to search through.
  • Clean design that doesn’t snag on things. Doesn’t extend out past the side of your body or have bulges or loose strap loops to catch on branches.
  • Shoulder straps that allow hydration tube or mic cord routing. Prevents the hydration tube or mic cord will not catch on things.
  • Compression straps on the side. When the pack isn’t full, compression straps keep the pack working as an extension of your body. None of your gear is flopping around.
  • Back protection. Hard objects in the pack can injure your back if landing on firm snow or an object. Best to have some protection, not just a thin layer of material. I purposely do not keep aluminum water bottles close to the back.
  • Wide range of adjustments. Waist and shoulder sizes vary, make sure the pack can accommodate you.
  • Hydration-compatible. This is a must for summer sports. In the winter, I’ll keep an insulated water bottle in my tunnel bag.
  • Options for shovel carry. Inside sleeve for probe, so it doesn’t ice up, different ways to store shovel depending on your preference.

Snowmobilers: Should you choose a Float MtnPro Vest Airbag Pack or another Float Airbag Pack model?

Advantages of a Float MtnPro Vest Airbag Pack:

BCA Float MtnPro vests have three size options: small, medium/large, and XL/XXL. You put on one device that encompasses the radio, transceiver, airbag pack, and protection. Easier access to the transceiver for transceiver checks and rescue. I feel the vest is more comfortable than a pack, really takes the weight off the shoulders. With a vest, there’s no problem with getting objects adjusted that are under or over a jacket (i.e. chest protector, transceiver harness, pack). Getting those layers to work together can be a bit of a headache at times, not a problem with a vest.

  • Breathability: The vest should allow airflow and heat to escape through it. This is accomplished by vent holes and material that breathes. Some designs just don’t breathe. It’s a key design consideration with BCA. We get some complaints from people saying the vest is hot, the problem is often the jacket they are wearing doesn’t breathe very well. Change jackets or wear fewer layers and the problem disappears.
  • Waist belt. No waist belt, the vest bounces up and down. To prevent it, you have to tighten adjustments around the torso, which can restrict your breathing. A better option is a vest with a waist belt.

Advantages of a Float Airbag Pack:

More variety, styles, and size options - and they are lighter!

Get a pack that fits you. You wouldn’t buy boots two sizes too big, get the right sized pack for all-day comfort. Size and proper adjustment are often overlooked but make all the difference.

Mike Duffy, Professional avalanche education for mountain riders.