Bushwalking Skills: Bushwalking Equipment | Adjusting The Harness of Your Bushwalking Backpack

Wednesday, June 15, 2011

Bushwalking Equipment | Adjusting The Harness of Your Bushwalking Backpack

Just bought a new backpack and forgot to ask how to adjust it? Heard conflicting methods? Feel that your pack needs some fine tuning to make it more comfortable?

Well there seem to be as many different opinions on how to adjust your pack as there are packs. Of course the three basic designs, internal frame, external frame, and no frame will each be different, but the general principles are the same.

Pack Size

However for adjustments to be comfortable you must start with a backpack that fits your body. Firstly you must select a pack which is the correct length for your torso length. Usually the manufacturer will have a diagram on their website which shows you how to measure this, but usually it is the distance in cm between the C7 cervical vertebra, the largest protrusion at the base of your neck and the iliac crest, the highest point on your hipbone, which can be found by running your fingers down you ribs. Men and women usually have different manufacturer's sizes for the same torso lengths and while related, body height is not the the perfect predictor of torso length.

Choosing the correct pack size

In some situations, where pack volume is more important, you may be forced to get a larger size, despite it not being a perfect fit.

If you have selected the correct size then it will be possible to adjust the attachment points of the shoulder straps to the pack so they are just below the tops of your shoulders (1-2", 2.5-5cm), while the waist belt will sit over your hip bone, not above it.

To help you adjust the harness of your bushwalking backpack, I suggest a full length mirror, a partly loaded pack and someone to help you hold the pack in position as you adjust the straps.

There are usually six straps that need to be adjusted:

hip belt (NB this is not meant to be a waist belt)
hip stabiliser
sternum
shoulder
load lifter
suspension adjustment

1. Put on your pack and lean forward, tightening your hip belt over your hip bone, so that the middle of the hip belt is covers the iliac crest ( top front of your hip bone) and the buckle covers your belly button. If the hip belt padding from each side touches when the belt is tightened then you have chosen a pack or a belt size (if removable) which is too small as the padding will prevent the hip belt being tightened sufficiently. You need to leave at least 3 cm either side of the buckle after the hip belt has been tightened to allow for different clothing thicknesses.

2. The hip stabiliser or anti-sway straps prevent your pack swinging from side to side as you walk, by pulling your pack closer to your hip belt.

3. The sternum strap should be half way between your breasts and collar bone and not so tight as to constrict your breathing. Its function is to stop your shoulder straps falling off your shoulders, not to carry the load. When tightened it also prevents your shoulder straps rubbing against your arms and armpits.

4. Shoulder straps should be adjusted evenly so that the pressure on each shoulder is the same and the pack is not tilting to one side. Generally speaking about a third of your weight should be on your shoulders and these straps proportion the weight between your shoulders and hips. Some people prefer to have 80-90% on the hips, so choose whatever feels comfortable for you at the time and feel free to change the proportion during the day as you develop sore spots. Tighten the shoulder straps and the weight goes from your hips to your shoulders. The shoulder straps should be in contact with your shoulders and you should not be able to place your hand between your shoulders and the strap. The pack attachment point should be just below the crest of your shoulders, and the bottom of the shoulder pad, a hand width below the top of your armpit.

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5. Load lifter straps should be evenly tightened and tight enough so that your pack does not hang away from your body, pulling you backwards, but rests against it. If the suspension is correctly adjusted, and you have purchased a pack that matches your body length, then the load lifter straps should be angled downwards from your pack to your shoulders at about 45°. They also shift some of the weight from the top of your shoulders to the upper chest area, but if the angle is too steep they will lift the shoulder straps from your shoulder.

6. The harness length can be adjust by lifting the lumbar padding and adjusting the buckle and strap or the velcro.

If the pack is still uncomfortable, then the internal frame stays may need to be removed and bent to more closely match your spinal curvature or perhaps curved away from your shoulder area to move the pack away from your head if it keeps bumping on it.

Comfort also depends on how you load your pack, with heavier items towards the middle near your shoulder blades to keep the centre of gravity close to your body. The lighter items such as clothing and sleeping bag can go at the bottom. Over riding this principle, you should keep the items you will need first in setting up camp near the top, especially if it is raining.

When crossing a river it is a good idea to undo the waist belt and sternum strap in case you need to jettison the pack, otherwise you can easily float down stream with it.