Zpacks Arc Blast torso sizing question

Sure, people have very different torso sizes and it is NOT just a linear relationship with height. I am a bit of a penguin myself. For years I have been telling women, "yeah I'm somewhat short, but I have the torso of a guy that is 6' 2". It makes them laugh, but unfortunately I never seem taller to them. :-)

Also I know that Joe (I think we had an email exchange on this one time) likes to use a longish torso length and have the straps go either straight back at the top, or even a bit up. I have even heard of more than one husband and wife team with almost a foot of difference in height that have the same torso length.

Just another reason why you have to measure. The good new is you can get the exact measurements from them, and when I ordered based on that it was an absolutely perfect fit – no surprises. So if you are worried there is something weird about the pack because of Joe's preference – don't.

I've measured three times but the "guessing" where the bottom of the belt rides is the only oddity. I'm gonna stick with the 22" and cross my fingers it works like the measuring tape says it will.

Thanks for the time to reply Mark.

I recently ordered this pack as well but haven't yet received it, and I'm not anywhere close to the same height as you, so I can't offer direct experience with the end result. I have, however, just gone through the measurement process and discussed it with Joe and others at Z.

>>"The zpacks hip belt is 4" inches wide I believe."

Correct.

>>"So if I split the hip belt difference I get 22" for where the bottom of the belt would ride."

You lost me here. Split the hip belt difference? Difference from what? You may mean from your current hip belt, and if so you are on the right path. What I did to measure is first measure the width of my current hip belt to know if the Arc's 4" would be the same or taller or shorter. From that I could determine where the bottom of a 4" belt would be on me. And then I followed Joe's directions, specifically that I did NOT measure my "torso" in the traditional sense (along the spine C7 to iliac crest) but rather used a yardstick from where bottom of the Arc's hip belt would be to the height at which I want the shoulder straps attached. This is how Joe shows to measure.

Joe says on the website that he personally likes the straps attached at about parallel to the top of his shoulders. I agree that in several of the photos the straps are actually a bit higher than the tops of his shoulders. Personally I like the shoulder straps to attach a little below my shoulders (so they curve around the top a bit) and then have load lifter to pull the top of the bag in closer above my shoulders. I measured myself this way to be 20" from bottom of hip belt placement to the top of my shoulders and so ordered 19". This happens to be the same as my torso measured the traditional way, but the key here is to measure the way Zpacks says to for their packs regardless of how you may measure for other company's packs.

" I have even heard of more than one husband and wife team with almost a foot of difference in height that have the same torso length."

That matches myself and my wife. 6'5" vs 5'6"…less than an inch of torso length difference. I'm all leg and she's all torso. We just did a weekend hike where she wore my Ohm.

Ryan

Thanks for the input JR.

I pretty much did exactly what you described but just didn't articulate it as well….

And to compound this sizing method even further, some people physiologically prefer wearing a hip belt higher (above the iliac crest) than lower (on or below the iliac crest.) With a heavy pack, this repositioning might occurr several times a day for a given individual.

And so, historically, how do you "prefer" wearing your pack?

Personally, at 6'2", and using the ArcBlast for just a few months now (carrying 25 lbs max.), I couldn't imagine having anything smaller or larger. But in all honesty, the fact that I'm NOT carrying as much weight now has as much to do with my overall comfort as the decent fit of the pack.

So for me, the large is a wonderful fit – again, for me. I stopped worrying about my torso length measurement (and bending aluminum stays) a long time ago. I just need to get "close enough" and see what the pack tells me.

Any good company will allow you to do that. If something's not feeling right, send it back.

My real torso size is 19.5" Im 5-9 with 32 inseam.

I have a regular torso in the arc blast. Followed Joes reccomendation, and it worked out great. Shoulder straps ride maybe 1/4" above my shoulders or so. Never have any weight on my shoulders, and pack doesnt try to lean backwards either at all. It works great.

Belt is extremely comfortable too.

Honestly, If in doubt discuss it with Joe and get his input before they begin to make your pack. You can change anything up to that point.

When in doubt just measure the geometry directly off a pack you know fits you the way you prefer (when loaded). Even if you only think this is the best fit (as is true with a lot of people), you will still be able to reproduce it. This will be flawless every time and is the only foolproof method – provided you actually have one that you think fits right already.

The only caveat is that it goes without saying that this may not work perfectly if you are doing apples and oranges, such as using the measurements of a giant pack with a super thick hipbelt designed to carry 90 lbs and buying a different style, such as an UL backpack. If the styles are completely different the ways you prefer to carry them may differ a bit.

Otherwise this method pretty much works on any pack you buy online, PROVIDED you ignore both the torso ratings and your personal torso measurement and can get a hold of the ACTUAL measurements from the company. Then you just compare the the measurements for the pack you want to buy with the template pack measurement when making your size selection. Works absolutely every single time.

So if you are very happy with the GG pack, measure THAT pack when configured how you like it if is adjustable. Middle of belt or bottom doesn't matter, just make it the same as the actual measurement they give you from the pack maker. Again, actual measurement NOT rating. I think zpacks when asked usually gives the measurement from the bottom of the belt.

I'm very similar in size to MB above, with 31-inch inseam. The medium Arc Blast with no extra lumbar pad and no load lifters. Extremely comfortable pack by any metric I can think of.

The way the back mesh panel is tensioned with the arcing stays, it can be tuned easily to match personal preferences. I would imagine that you'd have absolutely no problem with a large.

Thanks Bob…that is the kind of user feedback I was looking for.

I tried a stock 21" Arc Blast from Joe — and then had him custom make a 19.5" torso sized one for me that I used for my 2013 PCT thru-hike. 6'1" about 175 lbs and 32-34 waist.

How you like to wear the pack will make a big difference !

Shawn, you're probably right in the ballpark. I'm 6'3, 32" waist, and I believe my "torso" was a 23" measurement for the Arc Blast. I think usually I'm about 21.5 inches measured the more customary way. Just follow the instructions Joe provides for measuring and you should get a good fit, even it doesn't jive with your "normal" backpack torso length.

edited to add: the padded belt is 4" wide, so just figure where the center of the belt will hit, and measure from there, then add 2". The center will/should probably land on your pelvis bone (that thing that sticks out about where your belt usually goes).

Thanks Jacob….pretty did what you described. We shall see how it fits when it shows up on my door.

Shawn, I think you're going to be very happy. Unfortunately, the wait time looks to be pretty long right now. I ordered mine when the wait time was listed as 4 weeks and it ended up being almost 6 weeks. Whatever the wait, in the end it is well worth it.

Although mine is the 52-liter pack, in retrospect the 45-liter would have plenty of capacity with the UL load I am now carrying. No biggie, since the extra capacity costs only 1/2 oz compared to the 45 liter version, and I may need a little more space for puffies when next winter rolls around. In the meantime, the slight amount of extra material in top dry bag-style closure simply rolls down and makes for a nice, compact pack whatever the size of the load. The side compression cords work extremely well for such a minimalist design. Even the forward-canted water bottle pockets are a stroke of genius.