Companion forum thread to:

Lightweight Internal Frame Packs: a State of the Market Report - Part 2: The Packs

And I'm trying to wrangle all the mini-reviews so that this is also their forum. It's harder than it looks... but here's hoping!

UPDATE: +10 points for me!

Edited by addiebedford on 09/28/2010 14:17:26 MDT.

time to put on the asbestos suit ....

interesting that a Jansport that you can buy online for $50 got the same rating as many higher end packs including some cottage manufacturer ...

Edited by bearbreeder on 09/28/2010 15:07:01 MDT.

Thanks a lot Roger! I found your mini-reviews to be fair and informative. Worth waiting for :)

The comfort thing is the one issue that is, as you point out, impossible to get right. For instance, I found the GoLite Quest to be comfortable for weekend trips, but when loaded up for anything more, the pressure it put on my lumbar was unbearable. I find the Exos and Flash to both be comfortable with these heavier loads, and have no difficulty getting 10 days worth of (non-winter) gear and food into them. But I do make liberal use of all those frilly pockets to accomplish this ;) Couldn't agree more about those 'silly' whistles, but since I remove sternum straps anyway, they don't bother me.

> interesting that a Jansport that you can buy online for $50 got the same rating
> as many higher end packs including some cottage manufacturer ...

Take the Rating in the context of the Qualification! That modifies things slightly. But otherwise, a fair comment.

If you are going to make 10 packs in a garage, then you may be willing to tweak as you go. If you are going to get 1000 packs made in Asia in one batch, you had better have the design RIGHT before you send it off. That accounts for some of the design differences - maybe. I do know that in the case of the Jansport the pre-production prototypes were NOT as good as the final design!

But otherwise, I think the price difference is a reflection of the different manufacturing costs between American cottage and Asian factory.

Cheers

"interesting that a Jansport that you can buy online for $50 got the same rating as many higher end packs including some cottage manufacturer ..."

Actually, it's wonderful to have a low-price alternative available to suggest to those starting out backpacking with ultra-low budgets. College students come to mind!

The comfort thing is definitely an individual affair! IMHO, pack fit is almost as individual as shoe fit--there ain't no one size fits all!

Edited by hikinggranny on 09/28/2010 18:03:07 MDT.

Another fine report.

The upper left quadrant of the efficiency chart is empty. Wondering if that is an opportunity for someone or a reality for all.

>> If you are going to get 1000 packs made in Asia in one batch

Probably most made in the same facility with the same machines by the same sewers in Vietnam. None of which even comprehend the concept of backpacking. Not that it makes any difference. Only interesting to contemplate.

The individual reviews of the packs were quite interesting. I only have real familiarity with the Golite Odyssey which my daughter uses and the REI's. All of your observations were spot on. One thing I'd like to add about the Odyssey is that the original hipbelt buckle was very weak. I read an account of it failing somebody many miles in the mountains which produced a nightmarish exit. I requested a back-up from Golite which they sent me free of charge. It was much heavier and clicked in with twice the torque. My wife is using the predecessor to the Flash which had adjustable Velcro closures for torso. It's OK , but the volume is indeed skimpy, the compression system with internal cords a bit weird, but the rear "pocket" is actually a full kind of sling liked you described on the Lowepro's. Open at the top it offers a big volume for something like a wet tent.Your analysis of the panel loading pro's and cons of the ULA Camino applied very well to my Mountainsmith Ghost in terms of the zippers and the need to use compression straps to control any load on them . So I also will look at Osprey's in a different light now, and above all I like reading reviews by a couple of the same reviewers so there is some consistency in the ratings. And the revelations about volume are eye opening. Weight is one thing but I've felt that the volume, true load capacity and waterproofness variables have been subordinated to UL weight here at BPL fairly often. The hard thing to fathom is how much work this took. To consider an application of similar reviews to the rest of the pack universe is pretty daunting. Thanks for your hard work!And Roger would you consider any of these a keeper YOURSELF?Another forgotten variable is whether any of these lids actually can be taken off and turned into Daypacks? A major plus for the way I hike.

Edited by Meander on 09/28/2010 19:02:38 MDT.

here's a slightly diff look with the same data ...

as you can see the BPL vol vs weight is a tad eye opening ... the top in vol/wt is over 70% more efficient than the bottom

also note the USD/ vol ratio (converted at today's rate does not include shipping, I also adjusted the ULA to reflect the listed price) ... the worst value camino cost over 3x as much per L as the jansport best value one

interestingly enough those packs that had the better vol/wt ratio also tended to have the better usd/vol ratio as well ... in other words the more efficient packs were usually also the better deals

one thing that really stood out from the number was that the high denier "bombproof" packs dont pay much if any weight penalty over the more fragile fabrics ... the lightwaves, crux and jansports 400-600D+ fabrics give you as much vol per weight as the more fragile packs ... kind of pops the myth that you need to use UL fabrics to make a decently light pack =P

at the end of the day its what fits best ... nothing else is as important

Edited by bearbreeder on 09/29/2010 05:17:19 MDT.

Interesting. I sold my Exos 46 (the most painful pack in the history of the world) to buy a ULS Circuit, and couldn't be happier.

We've been thinking about pushing our Boy Scouts toward the Jansport, looks like that would be a good idea.

I've been using the Women's REI Flash 65 for 2 years now and your comments are exactly what I have found, esp. about the volume.

I do use the larger (fake) side pocket to hold a large 2 liter water bladder with drinking hose so I can keep my water outside of the pack. Works great for this and I really like it. Bladder doesn not flop over due to taller pocket. Hipbelt pocket is too small.

I bought and returned a lot of packs over the last few years because they were not comfortable. Although this pack isn't perfect, it's my favorite because it has the features that I like and it's comfortable. Hurray for having women's specific pack, REI! And I got it on sale for $104. Nice!

Sports science research shows that the most important factor determining the energy required to carry a given weight and to create the least strain on the body is the closeness of the center of gravity of the load to the center of gravity of the body. This has been found to be even more important than the weight/ volume ratio.
Lets call the distance between the center of gravity of the load and that of the body the load leverage distance. The greater this distance the more leverage the load creates on back and shoulders, increasing the forces acting on the body substantially above that due to the weight alone. Another important factor is the length of your back. A pack with the same weight and load leverage distance will create much higher forces on the body of a person with a short back, that a person with a long back. This is often the reason why short women in particular cannot carry the same loads as men. They have to work harder to carry the same weight.
Therefore for a pack comparison to be truly authoritative the load leverage distance should be included along with the weight/ volume ratio. A composite value combining these 2 factors would be highly accurate, and take a lot of the subjectivity out of a comparative analysis. You start with an accurate determination of the forces acting on the body by a given load due to the each design geometry. Once this is known, you can evaluate comfort much more accurately.
The load leverage distance is quite easy to determine. The packs can be filled with soft items like sleeping bags and the distance between the front and back of the pack at the mid height can be measured. Half of this distance would be the load leverage distance.
I believe Backpackinglight aims to provide the most authoritative analyses and product comparisons. This was certainly the case with the stove analyses done by Roger. I am disappointed that Roger did not provide the same hard-headed analysis for his pack comparison.

Aarn Tate

Hi John

> Roger would you consider any of these a keeper YOURSELF?
A very good question. many of them were very nice looking packs, very attractive.
But my good wife reminded my of the finite size of the planet Earth. Which means that our house and my gear cupboard also have a finite size. You can see where this is leading?

Yes, we kept a few, for specific functions. The rest have been passed on to Australian & NZ BPL members (kept the postage down) for further field testing. I expect that they will provide some Reader Reviews in due course.

> whether any of these lids actually can be taken off and turned into Daypacks?
Basically no, and that is a design which I strongly dislike anyhow. When I want a daypack I want a real daypack, with enough capacity and good scrub-bashing ability. My preference.

Cheers

Edited by rcaffin on 09/29/2010 16:20:58 MDT.

Hi Eric

> the BPL vol vs weight is a tad eye opening ... the top in vol/wt is over
> 70% more efficient than the bottom
True, very true. But note that I did add that that figure of merit does not include comfort.

> interestingly enough those packs that had the better vol/wt ratio also
> tended to have the better usd/vol ratio as well
I did not look at that figure of merit myself, so this is a valuable observation. It is especially relevant to novices and those of us with limited budgets. Thanks.

> kind of pops the myth that you need to use UL fabrics to make a decently light pack
Yes, I did note this. I think I commented on this in the assessment of the Shadow. It turns out that the harness is often a major weight factor, but it is the harness which gives the comfort. A trade-off, and everyone will have their own balance point.

Cheers

Hi Aarn

You are of course quite right that the 'load leverage distance' is of significance, and your web site does have a good discussion of this.

However, what I found was that there was little real difference between all the different models of packs. Sure, as the pack volume gets larger the CoG moves outwards a little bit - that has to be expected. However, I suspect the increase in weight carried might be more significant.

And what leverage difference there was could be easily swamped by how the user loads the pack. Putting a heavy wet tent in the back mesh pocket pulls the CoG away from your back perhaps more than the shape of the main bag. Where you stow three 1.25 L PET water bottles matters a lot: I put them high up and right against my back, which is very different from putting them on the outside (or back).

Yes, the size of the body carrying the pack also affects the load leverage, but I have NO control over that factor!

So I did look at the pack shape or load leverage factor, but I decided it was not all that significant in comparison with many other factors. In the end I left it out as I think that there are other more significant 'comfort' factors - although you may not agree. But discussion is always valuable.

Cheers

…Perhaps the Aarn method of measuring the Centre of Gravity (CoG) of a pack is less relevant to the reality practised by most people … ie most folks pack their pack so that the CoG is high and close to the body.

Was very keen on getting an Aarn recently… so had a read of the website … being an engineer I am very enthusiastic about new ideas and Aarn packs are a great example of bringing old and new concepts into an improved product … however it may be that some of the marketing is ‘jacking up’ a smaller issue… it seems, on face value, that CoG is one of them… the data example presented on the website (3-4kg of pull from a 16kg pack) seems to assume that the CoG of a pack was in the centre and bottom … whereas in practice high and close to the back is the norm…

Further to this…. we got back form a recent walk with a few packs (btw all of us liked the way the Aarn carried, albeit with caveats) but none of the other packs (all heavy load carriers ie around 2.5 to 3kg packs) were criticised for how they carried either.

The issue of CoG got our interest up (two of us anyway) so a small scratch pad analysis was done to measure at what weight our ‘normally packed’ packs CoG pulled our shoulder straps backwards. We attached digital scales to the front a few of the packs and slackened of the shoulder straps letting the load swing a little. There was 12 to 14kg in the packs and we measured between 130g and 210g of backwards pull... pretty rough and ready but we were happy enough with it. Certainly it reinforced our view that how you pack is more important to the effect of CoG than the pack in a general context.

Also that a heavy load carrying harness carries a lighter load ridiculously well and in many peoples opinion on the day it is worth taking a heavier pack just for this benefit – a view long held by this crew anyway. However, the Aarn carried beautifully also - so no complaints there at all – and it was lighter than the other packs.

Personally I am still a big fan of the Aarn system but for the overall integration rather than just the way it carries.

Edited by electricpanda on 09/29/2010 20:15:34 MDT.

Hi Dan

> We attached digital scales to the front a few of the packs and slackened of the
> shoulder straps letting the load swing a little. There was 12 to 14kg in the packs
> and we measured between 130g and 210g of backwards pull.

Blimey! That little? Makes the whole argument seem a bit ... pointless, doesn't it? I guess that includes a) a good supportive hip belt and b) you were leaning forward in the normal 'walk balance'.

But this sort of MEASURED data is what BPL is all about. Thank you!

Cheers

Of course the center of gravity of a pack can be measured. However, I agree with Roger that it's mostly how you load the pack. A lot also depends on just where the body's center of gravity is, which will differ by individual.

Being a woman who's rather broad across the beam, my center of gravity is quite low (close to where I sit!) and I load my pack accordingly--the heaviest stuff right above my sleeping bag (which is in the bottom) and as close as possible to my back. For a slender male with narrow hips and broad shoulders, the center of gravity for body and pack will be a lot higher (although still close to the back).

If a pack is so constructed so that you can't put the heaviest stuff where you need it, that would be a problem. I doubt that there are many of those around, though. I personally haven't seen one.

My pack loading problems come near the end of a trip when I've used up most of the food so there is really no item that is heavier than the rest. Of course the pack is a lot lighter by then!

Edited by hikinggranny on 09/30/2010 02:03:42 MDT.

The experiment is interesting but as Roger implys the amount the scales show depends on an unmeasured detail the forward lean. If you lean not terribly far forward you can get the scales to read zero! I read Aarns science as saying that it is likely that any forward lean has an energy cost. That is also how it feels to me.

Roger, We measured the pull on the shoulder straps standing up straight with the load necessarily supported by the hip belts.

The conundrum was how to measure how much we lean forward when we walk? (Personally I say bugger all if you have good core strength) We enthusiastically discussed this to gain no real answer ... so the plan evolved to walk around, get a good balance and 'feel' then come to a stop and measure. We had the scales already attached by fishing line to the tops of both shoulder pads. The measurer ensured the wearer was standing normally.

Also, like lots of folks, I have always attached water bottles or cameras to the front harness which we didn't test as we ran out of time but you would think would make a difference. Certainly with the Aarn pack with the pouches loaded correctly could be balanced very well.

I reckon if you were really keen you could devise a much better and more accurate set of data with tension scales attached to both shoulder harnesses. Not my field though.

Again, going by feel and to add a bit of qualitative data, there was no substantial pulling back … I must point out the packs were all 70L +, all weighing between around 2.7kg to 3 kg and had heavy load carrying harnesses. ie in all cases the front of the shoulder straps were attached to the bottom of a pack with a substantial pack frame and the rear of the shoulder straps attached either to the frame bars lower down or right down at the bottom of the pack. The hipbelts were all double density foam with HDPE framesheet to keep foam integrity under load tension. For the Aussies/Kiwi’s they were 2x Macpac, 1x Oneplanet and 1x Wilderness Equipment (with their new harness which we voted the best of the field).