Size of a daysack for hiking

Question

I'm trying to decide on daysack for light hiking (no mountains, clement weather). There's plenty of guides online, but I can't seem to make sense of them.

This one, for example says

20-30 Liters

Most daypacks fall under this category. These are made to include the essentials such as food for the day, light insulation layers (puffy or fleece jacket), rain shell, a headlamp, a small first aid kit, and a space blanket.

and

30-40 Liters

This is the category where most weekend and overnight backpacks fall under.

These backpacks could fit everything you’d need for a 2 or 3-day adventure, including a lightweight sleeping bag, food for up to 6 meals, hammock/lightweight tarp/ultralight one-person tent, small sleeping pad, underwear, and an extra pair of socks.

There are loads of similar examples on hiking websites and YouTube.

I've measured my stuff (plus some official measurements from the websites of stuff I haven't bought yet (I'm new to this)

• Tent - 6l

• Sleeping bag -8l (compressed)

• Bedmat - 2l

• 2l extra water

• 1l extra food

• 4l spare clothing

• 1l cooking pot

(I also measured all my day hike stuff using the DoE kit list - It comes to 15l)

That's 24l bare minimum for my overnight additions. So I can't see how whatever pack I get for camping, my daysack isn't going to want to be at least 24l less.

Yet every website and video I seem to find has a difference of less than half that (10l in the example above). Even the ultra lightweight stuff doesn't seem to gain much in volume (just weight).

So my question is basically what are people carrying in a daysack that needs 20-30l, and how are they adding only 10l to that to turn it into an overnight camping bag?

Answer 1

First of all, you may be able to get 1 1/2 buckets of water into a 15 l backpack (and I wouldn't even be too sure about that because they may have rounded, and the measurements may be the outside measurements), but that doesn't mean that you'll get your sleeping bag compressed to 8 l next to the 6 l tent inside said 15 l pack. Not to speak of the "bump" an airing system for your back causes - that may make a quite awkward shape for the compartment.

Much easier to strap down (= flat) a larger backpack which allows you to arrange stuff nicely close to your back.

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For day/single night outings I use a 45 - 55 l bag. I have a big one for longer/winter tours in addition, but no smaller one in regular use. Mostly because I like the back (and proper hip belt) of 50 l bag so much better that I consider it worth while carrying that bag even if it is almost empty.

Also, with some good friends I've found it a nice strategy to use one such backpack for two people and change whose back is wet every once in a while.

When is that bag "full"? In winter/cold-wet or unstable weather, when I have additional photo equipment (my tele lens alone is bigger than @Gabriel's tent...), when I bring the laptop as well because I combine work with a hike, when I use it for shopping. In contrast to @BenCrowell, I often carry (initially) substantially more than 2 l of water (in hot weather, I'm easily in the range of 1 l/h).
Also I use one of those old-fashioned foam pads that take up a lot of volume in exchange for being basically indestructible and lighter than most of the inflatble ones. Also the rest of my equipment is not volume optimized at all, most of it 3 or 4 seasons. Even though I could do perfectly well without stove for many multi-day tours (say, 3 seasons), I may consider the luxury of having hot coffee worth bringing my stove for just one night... And that's a gasoline one. (I'm in Germany, lighting a wood fire in a forest is basically a BIG no-no over here)

Iow: as long the bulk or weight doesn't disturb you, it's fine to bring it. For an alpine tour with lots of elevation, I think harder about what exactly to bring (but then, many of these things become a safety consideration and you bring them anyways).

Answer 2

I tend to buy big, then use the side compression straps to shrink it to that the load covers my back. This allows me to take a fairly complete camera kit as well as a sleeping bag and emergency tarp, spare clothing for a winter day trip that may turn into a winter overnight.

I don't like little packs without a waist belt. I want a pack that goes from my hip bones to my shoulders at minimum. Smaller ones tend to either be useless for anything more than a windbreaker and a roll of toilet paper, or dig into shoulders and small of my back, and flop all over in rough terrain.

For longer trips I use an external frame Greggory (no longer made) that has a fairly modest main compartment, but has a shelf on the bottom and on the top. Food goes in a sleeping bag stuff sack on top, sleeping bag and foam pad and tarp go on the bottom. Tripod is fastene with ladderlock straps to the side frame.

Answer 3

If you're going to buy small backpack, like 20-30 liters, do not overthink and take simple model without much extras like the internal metal frame. Cheap simple backpack will work better because it's easier to bend and hide under your seat while commuting etc. It's just an universal backpack that you take for short hikes, small groceries or commuting.

A bigger backpack will also be your friend. It would work fine for bigger groceries, short trips with sleeping over in hotel, or backpacking with an ultra light tent.

A bigger backpack (70 liters or more) would be perfect for longer trips, like vacation.

So unless you're extremely tight on budget, owning at least 3 sizes of backpacks is certainly a good invested money. They are not only for outdoors, but replace a purse or suitcase in the everyday life.

The question how big backpack you need for a trip is practically unanswerable. This depends on so many factors. Having 3 backpacks you just start packing, and if it's not enough, you decide between taking bigger backpack or reducing your stuff. Some people go really extreme, eg. taking only 2 pairs of socks, even for a 2 week hike. Guess they sit alone even in an overcrowded train ^^ ...

Answer 4

Welcome to outdoors.SE!

The day packs I own are 16, 23 and 30 liters. The overnight backpacking packs I own are 66, 70, and 75 liters. However, all of the large ones have features that allow their volume to be shrunk quite a bit, and I'm often not using the whole volume. You can shrink their volume using compression straps or by not extending the top of the pack up to its full height.

How much volume you'll need depends on a lot of different factors and choices. Do you keep your sleeping pad inside or outside the pack? Are you in an area where bear canisters are required?

On your list, a lot of items seem pretty bulky. I would not carry 4 l of spare clothes. The tent and sleeping bag sound big and bulky. One of the things you're paying for in an expensive down bag is the ability to pack it down very small. Ultralight tents are much, much smaller than what you're describing.

If you're going to a dry area like California, then I'd question whether you need the gigantic bulky tent. You could just bring a tarp in case it rains.

If you're going to a wet area like England, then I'd question why you'd ever need to carry 2 liters of water on your back. Even here in California, I seldom need to carry that much.