Puma concolor wrote: Anyone who tells you that a 100L pack is too large simply doesn't have experience on expeditions or big climbs where you are carrying a lot of gear in addition to standard hiker backpacking fare.

If you carrying a 100 liter pack you are certainly not doing any climbing. Walking yes, climbing no.

Puma concolor wrote:And just to throw it out there, in addition to my full 100L pack on Denali, I was also hauling a completely full sled behind me. Anyone who tells you that a 100L pack is too large simply doesn't have experience on expeditions or big climbs where you are carrying a lot of gear in addition to standard hiker backpacking fare.

Well, I could certainly buy a 100 litre and I'm pretty sure I would fill that bag up completely. If you have space, you use it, i.e. dont bothering compressing stuff that much or at all. So I'm pretty sure most people using a 100 litre backpack will always claim "it was required".

For me all years of experience have tought me that cutting sizing and weight, actually makes alot of difference in the total. 200 grams there, 450 grams there, and suddenly you're ending up with less weight, being alot more versatile and most of all, you save energy for the mountain itself. I rather spend those grams on a really good down parka for safety and comfort, rather than useless backpack storage.

With that said, I had a test walk yesterday with my 75 litres new backpack fully loaded with my expedition gear for Denali & Vinson without any hassle. That included harness, helmet, ice axes, high altitude boots and stuff I will actually wear later on. The only thing I did not include was snow shoes and food/group gear. For Denali, the latter is what's going to be on the sled.

I believe what really affects the required volume of the backpack, is how you succeed compressing your sleeping bag. All other stuff usually takes no space at all. Even a big down parka is easily stuffed and if needed compressed, but the sleeping bag can easily end up taking half of your backpack's volume. I was soo close in succeeding using a 45 litre backpack now for Elbrus (north side expedition), but I just couldn't compress the sleeping enough.

Personally, I cannot think of any expedition where I would want to have a 100 L bag. As Damian said above, "gear expands to fill the space available". And if I totally fill up the biggest bag that I have (65+15L) with stuff, it gets so heavy that I can just about hike uphill with it. Forget about climbing with it. With an additional 20 L filled with gear, I couldn't move my pack anymore!

There are two pack sizes that I do almost all of my climbing with. When I want to bring more gear than I can fit in the pack I want to use, I attach stuff like helmet and mountaineering boots to the outside. And I can wedge items like my tent and ropes under the lid, so they hardly take up any space inside the bag. With those tactics, a 45-55L pack is fine as long as it's no more than a couple of days, and the weight won't be more than 20 kg. For up to a week or so, I go with 70-75 L. If I want to go on a longer expedition, I'll need more supplies, but I'll never be carrying everything at the same time, so I still don't need a bigger bag; I need a second one, and mules or a helicopter or something to get that second bag to base camp. I'm not going to hike in with a 100 L bag. Ever. If I would manage to get to the mountain in the first place, I'd be dead tired already before climbing it!

Puma concolor wrote:Wait. Wut?

I thought you'd climbed Denali.

Did you start going straight up 55 degrees slopes from base camp or did it take awhile to haul all your shit to where it needed to be?

I carried my expedition pack, which is roughly 75 liters and pulled a sled the first two days, to the 11k camp. I did double carries to 14k and 17k. Even with the extra gear (ice tools, rock gear, ice screws) that we brought for the West Rib, my pack never weighed more than 50 lbs, my sled never much more than 40. My pack was never over stuffed and did not have anything hanging off it that didn't belong on the outside (ice tools/shovel/foam pad). My approach was to carry 6 days of food/fuel so if my sled was lost I would have enough supplies. Probably the big thing here is, I climbed a number of biggish (i.e. AK Grade IV+) technical routes in Alaska before Denali, so I already knew how to pack for climbing technical rock and vertical ice.

What is the old saying?

Gather everything you would want on an expedition. Remove from it those items you can reasonably do without. Bring half of the rest with you...

Same goes for packs. Smaller packs are better (as people already pointed out).

If you need to climb, you'll need more of a climbing pack then hiking and hauling pack. Our team of 8, carried Wild Things Andinistas (4,000 cu.i.) all the way to 8,000 meters. There was absolutely no need for anything bigger. Learn to climb without excess gear...Everything is much easier that way.

Don't have much to add to what others with extensive mountaineering experience have already said. If you have a big pack, you are going to fill it out. Having a smaller pack forces you to be smarter about gear selection and packing.

Speaking from my experience of expedition climbing worldwide of peaks ranging from 6,000-8,000m peaks, from 5 days - 6 weeks, on technical and non-technical climbs, you do not need anything bigger than a 65L. Anything bigger and you will fill it up, carry a gigantic load and get wasted just trying to get to base camp. Denali might be the only exception to this. I had an 85L pack on this climb but never filled it out completely. I had 50/50 load between the pack and sled.

The one time I did max out my 85L pack, it was 70lbs+ and I was trying to do the JMT with no resupply over two weeks. It was pure hell and I suffered greatly. Remember that in the mountaineering world, smaller and lighter is better. If you see a dude shouldering a giant pack, he's just getting into it and doesn't know any better.