View Full Version : figuring out pack size
stonedflea
02-19-2011, 19:46
okay, soo... i went to a military surplus store a few weeks ago and found a possible pack for my thru. i didn't get it that day, but i took the measurements of it and i've tried looking it up online but no one really has any information on it since it's just a generic pack.
how do you figure out the size of your pack in cubic inches? what's the formula for that?
the measurements of the pack are 22x20x19, which, when i go to get the volume of the pack (lxwxh, right?) it totals 8360. i'm stuck as to where to go from there.
thanks y'all. this is the exact reason why i didn't major in math. :)
stonedflea
02-19-2011, 20:07
thanks toli, but... that didn't help me at all. aren't packs measured in cubic inches? when i clicked on the "volume" calculator, it only gave options for a cube or something with a radius. when i clicked on the volume converter, that didn't help either because ... well because i don't know what i'm trying to figure out, really.
plus, i'd rather not have a calculator do it for me. i'd actually like to know the formula for how to figure it out so i don't need a computer in front of me if i'm ever in this situation again.
i'm just not very good at left-brain stuff.
4eyedbuzzard
02-19-2011, 20:33
22x20x19?
That would be a very deep pack - and by deep I don't mean vertical top to bottom, but measured from your spine outward. It would be VERY uncomfortable as it would be pulling you over backwards (the further away the load is from your spine the bigger a lever it has to pull on your shoulders). You don't want anything more than about 8" or 9" in depth - the deepest / thickest item you carry should be your stuffed sleeping bag. Many good packs have straps to compress and stabilize the load and keep it as close to your spine as possible.
Military surplus packs like MOLLE's and ALICE's are good for carrying the military gear they were designed for. They pretty much suck for civilian backpacking unless you're a soldier of fortune or something.
4eyedbuzzard
02-19-2011, 20:37
Oh, and a 60 liter pack is plenty big for a thru. Look at a few Gregorys, Granite Gears, ULAs, etc to get an idea of how good packs keep the load close to your spine - and your center of gravity. None will be any thicker back to front than what is required - generally about 8" to 9" or so.
how do you figure out the size of your pack in cubic inches? what's the formula for that?
the measurements of the pack are 22x20x19, which, when i go to get the volume of the pack (lxwxh, right?) it totals 8360. i'm stuck as to where to go from there.
thanks y'all. this is the exact reason why i didn't major in math. :)
Your math skills are better than you give yourself credit for. You've answered your own question.
Given your measurements, the volume of the pack is 8360 cubic inches, which is equivalent to 137 liters (http://www.google.com/search?sclient=psy&hl=en&complete=0&site=webhp&source=hp&q=8360+cubic+inches+to+liters&btnG=Search).
4eyedbuzzard
02-19-2011, 20:50
And by the way, those are pretty much the exact dimensions of an ALICE pack. Do yourself a favor and go look at civilian gear.
Sounds like an ideal pack if you want to carry alotta popcorn.
stonedflea
02-19-2011, 22:40
And by the way, those are pretty much the exact dimensions of an ALICE pack. Do yourself a favor and go look at civilian gear.
it actually was the alice pack i was looking into. and thanks for your input about center of balance. i was basically just looking into things because my funds are gonna be pretty limited for my thru, and the guy told me he'd sell me the pack for $40. a huge pack like that for $40 seemed like a pretty decent deal to me at the time. meh... what you said makes complete sense, but it makes my budget frown, haha.
Your math skills are better than you give yourself credit for. You've answered your own question.
Given your measurements, the volume of the pack is 8360 cubic inches, which is equivalent to 137 liters (http://www.google.com/search?sclient=psy&hl=en&complete=0&site=webhp&source=hp&q=8360+cubic+inches+to+liters&btnG=Search).
thanks roland. :) i guess that just seemed ginormous to me. i guess, technically, 22x20x19 is ginormous. plus, i found a random website that quoted 6someodd000 cubic inches for the pack, and the two numbers just didn't add up. i couldn't figure how they got 6k but i was getting 8k.
Diatribe
02-19-2011, 23:10
hey Stonedflea: buying a pack is an important endeavor. it is one article of gear that you dont want to spend 50 bucks on, unless it's some great deal from a friend AND an Osprey pack. You're going to have to spend over a hundred bucks on a comfortable pack with a respectable suspension system--there's no way around it. Even if it takes some type of strict financial regiment for two months to save for it, it's worth the money spent wisely at the end of a long day of hiking.
A 60 Liter pack is also a great sized pack
May I recommend saving for an Osprey. I find their designs ingenious & the comfort is worth the money.
Just my two cents
bigcranky
02-19-2011, 23:11
I understand the budget thing, but really, avoid anything that big and that cheap. You have to use this to carry all your gear to Katahdin, after all. After shoes, the pack makes the biggest difference in daily comfort, I think. (I would say to avoid mil surplus in general, since military grade stuff is built to withstand much more abuse than you'll need on the trail, which makes it heavier than needed. But there is some clothing and other items that would work fine on a hike.)
You can get a nice choice of packs designed for long distance hiking for $150 or so, especially on sale. Look for something around 60 liters or 3600-4000 cubic inches that has an internal frame and weighs around 3 pounds total. Your avatar suggests that you are a female-type person, and most manufacturers make female-specific packs with narrower shoulder straps and a better fitting hip belt.
You could do a lot worse than the REI Flash 65 pack (http://www.rei.com/product/778471), for example. It's often on sale, or if you are a member they have frequent 20% off coupons.
Here's a link to some clearance packs at REI http://tinyurl.com/4ps7zeo
Also, check out the for sale forums here and on backpackinglight.com
Toolumpy
02-20-2011, 00:01
Try this site for matrix and standard conversions.
http://www.metric-conversions.org/
Has worked for me many times
stonedflea
02-20-2011, 00:24
thanks y'all :)
how do you figure out the size of your pack in cubic inches? what's the formula for that?
Backpackinglight recently ran a state of the market report for packs, and tackled this question. Here's a bit of a quote:
"Trying to calculate the pack volume is hopeless: none of the shapes are either square or round. About the only reliable way to assess the volume of the main bag is to fill it up with something like sawdust or polystyrene foam 'packing peanuts', and then to measure the amount used in a nice rectangular box which can be accurately measured. In fact there is an ASTM Standard for this, using 20 mm hollow plastic spheres (essentially ping pong balls)."
The rest of the article is here:
http://www.backpackinglight.com/cgi-bin/backpackinglight/lw_internal_frame_packs_part_1a.html
Wolf - 23000
02-20-2011, 01:03
Stonedflea,
Finding the right pack is a personal preference. What maybe the most comfortable pack to someone else may be extremely uncomfortable to you – even if you are the same body frame.
My suggestion is this, buy the rest of your gear first and then decided what pack size you will need. Your pack should be able to fit all your gear inside plus some extra room for food. When picking out your pack, take your time. Every pack is comfortable when it is empty so throw some weight inside the pack equal to what you are planning to carry and see how it feels. Walk around a little. If it doesn’t feel right in the store then it will be more annoying on the trail.
V/R
Wolf
kayak karl
02-20-2011, 01:42
wolf is right, but i would take food bag and 2 liters of water also. wear it for awhile. i walked with mine for 1 hour from store to store in the plaza.
it actually was the alice pack i was looking into. . . .Do yourself a favor. Check REI Outlet, Campsaver, anywhere else you can get a good pack on the cheap. After carrying an Alice pack for years in the Marines, all I can say is that it's a big, heavy, uncomfortable piece of gear. If you're leaving on a thru, you'll ditch it at Mountain Crossings.