How do you fit the G4 to fit your torso length

[Lisa C]

I have bought the pattern for the G4 with all the material and instructions to make my first backpack. I made the shoulder straps from my Osprey Ariel 55 and also the hip belt as this pack fits like a glove for me. (The pattern straps were too big and the hip belt not supported enough for my back). I sewed and placed them approximately where the pattern says to place them. Way to long for my 17″ torso. My question to anyone who has made a backpack before is how do you correlate the strap and hip belt placement to make it fit your torso. It’s kinda hard since the pack isn’t sewn together and you just have a piece of material everything is attached to. Trying it on isn’t working and a flat measurement doesn’t feel right when I put it on.

[Sam C]

I have built the kit (from Quest Outfitters) “as is” and have done numerous G4 (10 – 12) builds over the years that were modded in one way or another.   The instructions, and Van Peski’s ideas, are a bit wonky here.  For one, you are supposed to place the shoulder straps the length of your pad.  The pad, specifically mentioned, is a Thermorest at 20″ wide.  iirc, Van Peski uses/used a Thermorest cut down to 15″.  A size wide Thermorest will drop the bottom of the pad to the bottom of the pack, where it should be imo.

The torso length, if kept as is per instructions, is 24″.  Keep in mind that you are supposed to use a folded up sleep pad in place of the back pad, and depending on the thickness of the folded-up pad, this will reduce the torso length a little bit.  For example, on my “as is” build, if I fold my Thermorest Ridgerest (sized Regular), the torso length is reduced by about two inches or so.

Ven Peski loves to use size ranges that can vary by, what, 4 inches?  That’s crazy.  He recommends that a taller backpacker (that is, taller than 6′ 4″) raise the shoulder straps by one inch and that a shorter backpacker (under 5′ 7″) lower it by one inch.  But hey, some hikers swear by GG.

Anyways, to lower the the straps for a custom fit, keep the hip belt where it is supposed to go and measure up from the bottom of the pack your torso length.  Place the straps there, and that is it.  You will find that you know have ten inches of “top of the back” in addition to the whacky 12″ collar, which is too much unsupported space/structure above your shoulders.  So, you might want to trim the pack down.

Personally, I would also lower the hip belt to have it flush with the bottom.  If you were to use the original G4 hip belt, you’d also need to drop the shoulder straps an additional inch or two.

From a pattern, shoulder straps look as though they’d be huge.  Between the seam allowance and thickness of padding,  you’ll lose around 1″ from the width of the pattern piece to the width of the built strap.  So, with 3/8″ foam padding and 3/8″ seam allowances, the straps come out to be 3 inches wide.

I personally find the hip belt to be okay, but prefer taller ones myself.  The problem with the design is that the bottom of the pack is 15″ wide if you are going with the hip flares, or whatever they are called.  I am a big guy, and having the hip belt wings attach to the sides of the bottom panels is too wide even for me.

If the above is not clear, or you have any more questions, I can answer more later.

[Monique Schaefers]

@crucial-geek –

I am a 5’10” woman so the height of the average American male.  When I have been measured for packs my back is 18″.  Is this the length I should choose to cut my Zlite down to?  Is 18″ the number I should work with when placing the lycra mesh – 18+1 inch for distance of the lycra/grosgrain edges?

Thanks for your wisdom, time and consideration!

-monique

[Sam C]

@monique,

To be frank, going by torso length alone to fit a pack is not as simple as “the industry” would like to have you believe.  To give some quick background:  the reason why we measure from C7 to top of illiac crest are that these are easily identifiable and found landmarks.  It also turns out that the C7 is roughly one inch above the center point of each shoulder and that the top of the illiac crest is roughly one inch above your true waist line.  As you can see, your torso length here is really the distance from your waistline to your shoulders’ midpoints.  In reality, you should measure from the waistline then subtract 0 – 2 inches depending on how much you want the strap to curve around your shoulders and depending on the design of the hip belt.

The problem here is, where is the waistline on the G4?  If you go by the instruction (which assumes a 20″ wide pad), which is about 4″ up from the bottom iirc.  If you want to keep everything as is, then yes, you will have to cut down your ZLite.

 

A better alternative to my words above is to experiment.  I like to cut the back panel, shoulder straps, and hip belt from paper grocery bags and tape them together in mock construction.  This will give you a better idea of what you need to do.

But yes, as a general rule of thumb measuring up from the bottom your torso length is what you would do if you otherwise don’t know what else to do.

You can also check out the Yahoo user group dedicated to MYOGing the G4.  It hasn’t been active in about a year or so.  It’s full of good info, plenty of pics, the instruction “booklet” in downloadable pdf format (this is the same set of instructions you would get from Quest), which is only slightly different from the original document found elsewhere online.  The group requires a Yahoo email account, which of course you could create just to access the group.

[Sam C]

Forgot to mention:  you can also place the pad inside of the pack, which would give a little more stiffness above the should straps.

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