View Full Version : technical backpack question
this is a two parter:
1). How do they figure the capacity of backpacks (volume)?
2). how is it that a pack that measures 27"x14"x7.5" and says it's a 45 liter pack (2750 cu.in.) have less capacity than a pack that measures 26"x12"x10" and claims to be a 65 liter/4000 cu.in.pack?
hoyawolf
08-19-2008, 15:08
which packs are you talking about? perhaps the larger pack is including any "expansion" by the snow/drift collar?
like in cycling there are no industry standards in sizes and weights so there will be variation between manufacturers.
mister krabs
08-19-2008, 15:09
math is part of it 27*14*7.5 = 2835 26*12*10 = 3120
Maybe pockets is the other part.
yeah math, that's what I thought too but 800 plus cu.in. in pockets I thought was a lot. that's what I get for thinkin'
NICKTHEGREEK
08-19-2008, 15:38
Pack shapes are irregular and can't be defined by the simplified HxWxD. The pack is filled with media that can easily be measured for volume.
I have never bothered to do it, but I have seen post on WB, that suggest you take those packing peanuts and fill your pack. Then dump them in a square box, and measure the volume. If you really want to know.
I think that pack capacity is determined by stuffing the pack and all the pockets with little balls, maybe like ping pong balls or smaller.
Add in the front pocket, the top pocket, water bottle holders, hip belt pockets...
Whatever it takes to get that number as high as possible.
The Weasel
08-20-2008, 16:12
Most effective is clean sand, or a small grain (such as corn) or dry beans. Then the medium is poured into a measuring bucket. Dog food (dry, yeah, canned is messy) is also good but yeah, wash the pack afterwards.
Rusty