Osprey sizing... wild

[G-FOURce]

Check out the attached picture. On the right is an Osprey 35 and on the left is an Osprey 50. Both packs feature the same suspension design and both are a size medium. The frame on the 35 is 19.75" long but the frame on the 50 is 22.25" long. The 50 fits me beautifully while the 35 is way too small. Go figure. Anyone else see this kind of disparity between two Osprey packs of the same size in the same product line?

[G-FOURce]

I forgot to mention that they're both Atmos packs. The red is an Atmos 35 and the gray is an Atmos 50, so same manufacturer and same product line.

[Traveler]

I believe its the payload capacity of the back that determines its overall hight from the bottom of the pack to the top, which requires a taller or shorter back panel to support the load. That also impacts the type, size, and structure of the suspension system that will be less robust for a smaller capacity pack. The Atmos 35 was designed as a light load pack for day or intermittent use, the Atmos 50 is designed for many days on a trail and heavier loads.

There is an outside chance the packs were mislabeled (the medium actually being a small or being a large), however the pack structure looks correct for the capacity.

[G-FOURce]

That makes sense. I put a lighter load in it, about 8lbs, and the shoulder harness still feels unusually short. Maybe its just that I am new to ultralight backpacking and the harness shouldnt wrap down as far as those on a pack designed for 25-30lbs. Meh...

[Secondmouse]

yeah, I would expect that. a 35L pack isn't going to be as tall as a 50 unless it's the diameter of a mailing tube.

in my experience, the problem lies with them attempting to make valid use of the waistbelt. a pack that short either has the belt on your waist with reeeeally long shoulder straps, or the pack on your shoulders with the waist belt between your navel and your diaphragm.

IMO, Osprey isn't doing themselves any favors by trying to push the Atmos system down this low. fit is the key to comfort. these smaller packs don't carry enough weight to need a true waistbelt, however, you would benefit from a "stabilizer strap" around your body to keep the pack from flopping around...

[G-FOURce]

Its an older bag, and Osprey doesn't make the Atmos in anything smaller than a 50L now, so your opinion was on point there. And the assessment of the long shoulder harness made me consider the design a bit more and thats right on point, too. In order to use the same basic frame design, it would have to be wide enough to utilize the same belt which means they couldn't go taller without sacrificing too much depth if they kept the 35L volume. I bought a used Atmos 35 in a size Large so we will see how that works when it gets here. Luckily, my son can use the Medium so it looks like it will work out just fine.

[Secondmouse]

Its an older bag, and Osprey doesn't make the Atmos in anything smaller than a 50L now, so your opinion was on point there. And the assessment of the long shoulder harness made me consider the design a bit more and thats right on point, too. In order to use the same basic frame design, it would have to be wide enough to utilize the same belt which means they couldn't go taller without sacrificing too much depth if they kept the 35L volume. I bought a used Atmos 35 in a size Large so we will see how that works when it gets here. Luckily, my son can use the Medium so it looks like it will work out just fine.

yeah, I agree. those smaller bags with "real" waist belts should be relabeled for women or youth.

what I am using a lot, especially when it's warmer, is a MountainSmith Day lumbar pack. it has a legit waist belt and using the "strapettes" for the shoulder, it holds plenty for a day or overnight while keeping my back cool.

Glen Van Peski, the guy who started Gossamer gear was able to use one for a weekend but that would be really stretching it for me -- http://www.imgrum.net/media/1050204915807534628_215191262

[G-FOURce]

Dont think I would want to use a lumbar pack. I like light, but thats a bit too minimalist for me.

[Traveler]

Some folks see lumbar packs as fanny packs on steroids, but some lumbar packs are pretty versatile and worth a look. I have used one for a lot of years even doing short overnights here and there. The Browning Billy 1500 is similar to what I use in this class of pack, though mine was from Eastern Mountain Sports who no longer has them private labeled.

As a day pack, they are just about perfect, however I stretch the designed day use into one night (and have done two nights) use. I can put an amazing amount of gear into this little pack, with some creative use of strapping and carabiners I can put a variety of things onto it without much trouble as well. The shoulder straps make this expanded use possible, help load distribution, and keeps the pack stable.

The list of things I can keep in and/or attached to this pack at one time are:

3-L hydration bladder
Spare tech fabric base shirt
Pull over hat and smart wool gloves
Rain/wind jacket
Down jacket
Thermos with hot soup (or Jet-Boil stove)
Survival kit (compass, fire start materials, headlamp, space blanket, small knife, etc)
Spare socks
Camera (DSLR)
Wallet
Map(s)
GPS and cell phone
Tent (single)
Sleeping bag (in compression sack)
Snow shoes/micro spikes (wearing one and the other lashed to the pack)

It seems like a lot of gear, but it can all be stashed or secured to this amazingly versatile type of pack. My hiking partner typically uses his lumbar pack on most all trips, unless we are doing more than a night out. For me, this pack is perhaps the most versatile pack I have ever owned.

[G-FOURce]

That looks like a comfortable lumbar pack, but at 2.5lbs it seems a bit heavy for a 25L pack. It does make me want to consider a smaller and lighter version of a lumbar pack that has an integrated shoulder harness.

[Secondmouse]

Dont think I would want to use a lumbar pack. I like light, but thats a bit too minimalist for me.

yeah, I use it mostly as an alternative to the hot, sweaty back syndrome. you can get a surprising amount of stuff in, and attached to it, for a big day or a minimalist over night.

if I need more capacity, I go up to a larger shoulder pack with better ventilation...

[G-FOURce]

I reached out to Osprey and they were designed correctly. I reloaded my medium-sized Atmos 35 and with the right weight its actually quite comfortable. I'll use my 50L for winter and my 35L for summer. All good now...

[Secondmouse]

Some folks see lumbar packs as fanny packs on steroids, but some lumbar packs are pretty versatile and worth a look. I have used one for a lot of years even doing short overnights here and there. The Browning Billy 1500 is similar to what I use in this class of pack, though mine was from Eastern Mountain Sports who no longer has them private labeled.

As a day pack, they are just about perfect, however I stretch the designed day use into one night (and have done two nights) use. I can put an amazing amount of gear into this little pack, with some creative use of strapping and carabiners I can put a variety of things onto it without much trouble as well. The shoulder straps make this expanded use possible, help load distribution, and keeps the pack stable.

The list of things I can keep in and/or attached to this pack at one time are:

3-L hydration bladder
Spare tech fabric base shirt
Pull over hat and smart wool gloves
Rain/wind jacket
Down jacket
Thermos with hot soup (or Jet-Boil stove)
Survival kit (compass, fire start materials, headlamp, space blanket, small knife, etc)
Spare socks
Camera (DSLR)
Wallet
Map(s)
GPS and cell phone
Tent (single)
Sleeping bag (in compression sack)
Snow shoes/micro spikes (wearing one and the other lashed to the pack)

It seems like a lot of gear, but it can all be stashed or secured to this amazingly versatile type of pack. My hiking partner typically uses his lumbar pack on most all trips, unless we are doing more than a night out. For me, this pack is perhaps the most versatile pack I have ever owned.

I got used to a lumbar pack for hunting, it keeps my arms free. I'm not where I can snowshoe or x-country ski but I have friends who tell me it's perfect for that while pulling a sled.

in the hot humid southeast it helps with sweaty back...