Pack size for UL thru-hiking – 40L too small?

Hi Andrea

running with a pack is a LOT harder than walking with one. Also, bigger packs meant for this generally have more substantial harnesses than small hydration packs, which transfer loads better to your body. So don't stress too much about that, you'll be fine.

40L is possible but it depends on a large number of factors. On a thru-hike having some extra space for times when you can't get your normal supplies of dehydrated compact hiking food is good insurance, especially if you are a bit inexperienced…you might misjudge resupplies and have to make do with stuffing a couple of loaves of bread and a bunch of bananas in, for example.

At other times, having a little extra volume is not that big a deal. Most larger packs have at least a little bit of compression strapping of some kind, and/or, you can just pack your quilt/sleeping bag much more loosely allowing it to expand to take up space (which is coincidentally better for it).

Make sure you go to a store if possible and try on a lot of packs, with weight in them. If you can, borrow a pack or to to try out on training walks just like you would with your ultra gear. Short overnight sub 24 hour hikes (even if you only do a couple of hours walking either side of camp) are a good easy way to build up experience. There are a lot of skills to learn to make life easier that don't necessarily cross over from ultra running. Some do.

Take a look at lots of gear lists on here, including what packs they are using to get a better grasp of what fits what.

Also, starting by picking your sleep system and shelter is probably a good way to start. Then you can start to gauge volumes better.

Best of luck :-)

If your hiking is going to require a bear canister, go with a 50L. Especially on 10 day trips. It will make life easier.

If a bear canister enters into the picture only infrequently,for say 5 or 6 days then a 40L will suffice.

IMHO, and all that ….

Here is a good new post by Andrew Skurka on food he's about to use on a trip. He doesn't have volume there, but you can gauge it from the pics. This is a good example of minimum volume per day…what he has there is about as small a volume as you can pick for food. Bank on double that for the same calories easily if you can't get backpacking specific foods.

http://andrewskurka.com/2014/week-of-backpacking-food-breakdown/

If you do some searching of some of the bear can threads there is a wealth of info on the forums about fitting x number of days foot into y canister, etc.

Andrea, 40L is enough to fit 10 days repackaged, carefully considered food and UL gear for me just fine. However, include a large bear can in that equation, it also fits, but become very close to a sliding block puzzle. I think I have slowly been converted to the idea of scaling up a bit to 50L+ if I have to do that long a segment without resupply. It cost very little added pack weight, and packing for the start doesn't become a complex mental exercise.

The Skurka pic there looks so healthy – all except the pringles. That looks almost exactly like what mine does, except I just caved and substitute snickers for my chocolate fix. Skurka is known for the motto: "you can never pack too much chocolate".

The HMG Windrider 2400 (40L) pack can carry a Bearikade Expedition bear canister, barely, thanks to the Y-strap on the top:

I used that pack for an unsupported 8-day trip this spring, with no bear canister or freeze-dried glop, and a 13.6 pound base weight (not UL). But I was carrying only 1.4 pounds per day of food.

Thru-hikers often want considerably more food after a while. Some hikers are capable of gorging in town and eating 2500 calories per day on the trail, while cranking out 20-30 mile days — not me!

If you are not in bear canister country, you could strap food or gear on the outside of your pack for the first few days of an extra-long section. Won’t be pretty, but most thru-hikers are not concerned about looks.

One more thought – a smaller pack forced me to take less crap, before I read Jardine’s books and “saw the light” :-)

But if I had to choose between a 40L pack that didn’t fit me well, and a 50L pack that weighed a few ounces more but fit like a dream, I’d take the 50L pack every time. Luckily, the Windrider 2400 fits me well.

— Rex

Great Skurka link – thanks! I am a 'regular' sized woman with a slightly depressed metabolism (don't ask or I just might tell), so 2500 might be more than enough for me even with 25+ mile days. How about 1 jar of peanut butter per day, plus 4 packs of instant coffee? (Only slightly kidding…)

Oh, and I wouldn't be running much if at all. Just because I do ultrarunning doesn't mean I'd do Scott Jaime style CT in 10 days. What I would do is get up at dawn and walk all friggin' day.

You all are right – some of this stuff I will have to figure out in real life. I *do* currently have a 40L pack (Osprey Tempest), which has a zillion bells and whistles and a frame and la-ti-da, for 1KG exactly. So, not bad, but not SUL. I'm OK with that.

I *do* get the idea behind not stuffing your super expensive sleeping bag down to the size of a bread loaf so that it lasts longer. Makes perfect sense.

I think I should post a gear list of what I already have so that the evolution can be measured. :)

First of all, a 40L pack is not too small. However, there are lots of "it depends" factors in there. It depends on where you are going to be and what you are trying to do. For example, if you are hiking 25 miles per day over trails, that means something. If you are going to be eating hot meals twice per day, then that means something. If you are going to be in freezing weather, then that means something.

Although many backpacks are sized in liter dimensions, often the total number includes things in external pockets, so the volume can be misleading. You want to sort that out for any pack. Personally, I think mostly in terms of cubic inches of volume. My rough rule of thumb is that 1000 cubic inches of volume will handle about ten pounds of contents, although that varies a lot. Another rule of thumb is that each day's worth of food may occupy 100 cubic inches of volume, although that one varies a lot also.

In the old days, I used to go out with a tiny 1500 cubic inch daypack, and it had everything that I needed for one week in summertime Yosemite.

So, with all of these varying factors, you want to make yourself a gear list, test it, and then see where this leads you.

–B.G.–

As you have a reasonable 40L pack already and some gear, then yep, do some test runs with everything you have. Do up a list first, if there's something you are missing find something to substitute for it for now (just to get a feel for volume).

Also, mess around with food lists. I think people under-rate them and concentrate more on gear lists, but I think food is much harder to get dialed in especially for long self supported hikes without resupply. Misjudging by 50g here and 50g there on a days menu, over 10 days, is a solid kg. Once you've sorted your big three of four, got a simple, light cook kit, minimal other essentials, its pretty hard to throw out your pack weight by 1kg! But it takes a lot of experience to be able to nail food perfectly without much thought.

You'll be hiking for months and the extra 10 or 15 liters will come in handy. When I did the PCT in 2013 I met a couple people with tiny packs and they were always stuffed to the brim. That takes more time in the morning to get ready since everything has to fit just right, more anxiety in town when you have to worry about whether or not you can fit that bag of potato chips you've been craving and more aggravation when you do have to carry a bear can for 200 miles. It's really not worth the 3 ounce weight savings.

There's also a big difference between day and overnight trips and a through hike. You need to love being outside everyday and ok without the usual comforts of warm beds, showers, etc until you get to town every 4 to 6 days for months on end. You also need to be ok with being away from friends and family for most or all of the trip. A lot of people quit because they miss their family or SO.

Definitely get out on some solo week long trips before you commit to a through hike. You'll be better prepared in a lot more ways than just gear.

Thanks so far, everyone. I'd love to have women chime in, too…. if there's any reading. :-)

My size panic started when I first got the Tempest 30L and then considered the 40L and then freaked out yet again when I read Meghan Hicks' account of her 6 days on the Tahoe Rim Trail with a 33L Talon pack (very similar to the two I have/had). However, her photos show the pack absolutely stuffed and then some.

So… 40 might just be about right. I know 1kg is damn heavy to y'all for a pack. We'll see how it goes. The frame is pretty nice.

One possibility is to bring a SUL daypack like that Sea-to-Summit, 2.3-ounce, 20-liter one (about $39). Wear it backwards, over your chest, the first few days. Eat your high-volume and, of course, your heaviest food first. Then tuck that pack away.

I prefer having some weight in front instead of all in back. I don't have to lean forward as much and my back feels better.

If your lunch food, trail snacks, and water are in the front pack, it is easy to nibble and sip as you keep hiking.

Oh, interesting idea David. I have the StS as my pillow/stuff sack/water carrier/Whitney day pack. How do you keep it from falling off? Maybe make sure the straps are pulled under and inside the regular pack straps, and underneath the back of the pack? Anyway, nice way to get an extra 20L in a pinch for a day or two, and might be better in a lot of ways than having heavy things dangling wildly off the pack itself.

Going to go try it now.:-)

Just thought I'd share… 40L is just right for me for bikepacking (distributed among bike bags) and for backpacking.

OK, you asked for women to chime in…so I'll give you my opinion FWIW…

I'm having trouble visualizing an no-resupply 8-10 day hike in a 40L pack. Even if you're not going to bear country (so no bear canister) — most places will be kind of chilly at night (extra warm clothes) and most women sleep colder than men (extra volume of sleeping bag/quilt/pad).

Sure, the base pack items' volume could easily be scrunched into a 40L, but 8-10 days of food??? You sure won't be eating much…which could make you colder (see women's need for warmer clothing/sleeping bag, above)…

Personally, I'll soon be heading out to bear canister country with a 10-day carry, and I'm seriously wondering whether my 60L capacity will be big enough…but then again, I've vowed to stop spending 15 minutes/day compressing my sleeping bag/pad into a tiny tight package. And my pack weighs (empty) about the same as yours.

It just seems as though, for a 1 kg empty pack weight, you could do better than a 40L, and have plenty of room for enough insulation and food to make it a safer, more comfortable trip. OTOH, if you're going out there to experience something similar to an ultrarun (long, fast hiking days, with only a brief sleep in between) your 40L pack should be enough (but you'd probably want to get a lighter pack).

Thank you, Valerie! That's kind of what I was looking for, especially the reminder about how we tend to sleep colder than average.

I am, however, planning on the strategy of either being hiking or sleeping 24/7, so camp comfort is not a major concern (though it also shouldn't be zero, of course).

What, no comments on the "all-peanut-butter, all-the-time" camping diet? ;-)

If you choose the right pack the extra 10 liters will not cost you much in weight of the pack itself. The real danger lies in lack of discipline. Some people NEED the size of the pack to help keep them from "creep." You know…"this only weighs one ounce, and I've got plenty of room." If you have discipline this is not an issue. Volume can be used to add extra weight (not good) or simply to avoid having to compress the hell out of everything and be uber-efficient in your packing as others have mentioned. I like having a bit of extra room so I don't fully compress my sleeping bag and so I can arrange the weight correctly without having to worry about having the weight fit into a jigsaw puzzle. I've seen people have to put heavy items on the outside edge of their packs to make everything fit, which totally negates the value of the small weight savings. Others may have figured their way around this with their specific equipment so your mileage may vary. I arrange things like I want and use my (partially) uncompressed sleeping bag and clothes and compression straps to keep everything tight.

IMO, your pack (volume) size isn't like your dress size… not really an achievement to pare down and fit into a smaller one. It's more like your shoe size; the right size is the one that can carry all your gear comfortably. I also wouldn't fixate on the volume; fit and adequate suspension for the weight of your gear is more important. Again, my opinion.

I'm a 5'2" woman and I carry a ULA Circuit. It's rarely close to full and I could easily carry a smaller-volumed pack but I just really like the way the Circuit distibutes and carries the weight. I also like not having to cram things in; I just pack it and then cinch down the side compression straps.

I think you'd have to pack super aggressively with a 40L pack for 10 days. I know I couldn't do it without "going without", which is something I'm not willing to do.

40L is not to small for an 8-10 day trip. Or even a thru-hike with a resupply every 8-10 days. I did a 14 day trip along the NPT with a 2200ci(35L) Murmur with a 32F outfit. A similar 20F outfit would have taken about 2500ci or about 40L. But you would have carried 4 days less supplies (mostly food and fuel.)

Typically, my pack weighs about 11oz. This is a Gossamer Gear Murmur. A similar Gorilla fared just as well, but really, I didn't need the extra space, I brought luxury items: a saw, water shoes, extra fuel for frying fish, some fishing gear, etc…

Depending on your gear, you can easily go lighter or smaller. Small light, small stove, bulk packaging (oatmeal in one bag, rice, noddles or pasta for example, maybe a salami or high fat substitute,) crushed Fritos or potatoe chips, chocolate bars, small pad, high FP bag (compressed,) heavy weight long johns, sleeping socks, shorts, shirt(both for doing laundry,) rain gear, etc…

Edited to add:
Yeh, I had forgotten that. A good jacket for really cold evenings, nights and mornings when you are not moving, yet. Mine is good to about 32F in the morning when coupled with a long sleved shirt (fleece or long johns.)

Actually, the all-peanut butter diet, if accompanied by adequate amounts of chocolate, sounds ok to me, LOL!! ;^)

I really agree with Sumi on the size question (and frankly, Sumi usually gives good advice in general, IMHO). Aside from "bragging rights" (ooooh, look at how tiny her pack is!) the important thing is to have a pack that's lightweight and carries/fits well. The volume can be adapted by using the compression straps.

I would also recommend that you not skimp too much on the insulating clothing — when the weather gets unexpectedly cold, a warm jacket can be used to augment your sleep system. Poor sleep makes the next day's hiking so much more difficult.

Enjoy yourself, and have a spoonful of peanut butter for me!

"Actually, the all-peanut butter diet, if accompanied by adequate amounts of chocolate, sounds ok to me"

Take one jar of peanut butter and one jar of Nutella.

–B.G.–

Could check out the PCT Blogs see what everyone is carrying (ULA,GG,osprey, ray-way,etc…) and how they handled their food/bear canisters
http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=91608&skip_to_post=781334#781334

Read where one lady with an Osprey Exos 46 w/a bear can which I'm assuming to mean canister. Link went bad (or I screwed it up) but these packs making it thru the Sierra (requiring a bear canister) should give an indication of minimum volumes if planning to hike an area where they are required.

ed: link

Marko: I learned the daypack-in-front trick on a GCNP death march. My companion bonked, so I carried his pack on my chest then put my daypack on normally on my back (thus, the normal pack's straps secured the front pack's straps). And it was, balance-wise, easier to carry than a single pack.

I suppose you could clip said daypack onto the front of your main pack's straps, somewhere above your pecs.

But back to the original Q – going to a smaller main pack. Wouldn't a smaller pack make my butt look bigger?

I have a base weight of about 14# for 3+ seasons (30F all day and above) and I use a 55L pack. I have carried as little as a 30L pack for multi day trips but in the end the larger and more featured pack wins.

Why? I like not having to very carefully pack my pack and I like having the overflow space for when I want to carry some luxuries. I carried full sized Crocs inside my pack as my one luxury last trip! Other times when I know it's going to be a cold wet trip I'll carry a thick fleece!

From a thru-hiking perspective having the extra overflow space will mean consumable luxuries. On cold wet mornings you can just cram your wet gear in the pack without carefully rolling and packing everything so you can get hiking and warm up. It also means when you resupply you can happily take an extra jar of peanut butter, a loaf of bread… Or even take out lunch from the last trail town!

Resist the urge to put things in your pack just because it fits… And having a slightly larger pack than you need will be a huge upside, never a downside. Finally, be sure that your new pack has a good compression system and carries comfortably without flopping even when it isn't stuffed to the brim.

David, I was looking at mine and if you crossed the thin webbing straps over, so left shoulder to right hip and vice versa then that would probably be awesome worn front-wize. Very secure under a regular pack But they are skimpy on the length. I guess you don't get down to 2.3 oz by playing around. Looks like it might be time for a super simple mod to replace these with longer straps.