Diminshing Returns?

[David Passey]

For the past few months, I have been hiking 3 to 6 miles most every morning, wearing a Gossamer Gear Whisper pack loaded to 12 lbs. I really like the pack–it's simple, sleek and carries the weight quite well, much better, in fact, than I expected. (My only suggestions for improvement are that the shoulder strap foam is too stiff and that it needs some way to carry water on the exterior of the pack–perhaps shoulder strap bungees).

As a test of the pack's comfort, tonight I loaded it inside my ULA Circuit and hiked for four miles around the neighborhood. My intention was (is) to pack in this format for the next couple of weeks to compare my relative comfort with the ULA to the GG. But the difference between the two in terms of comfort was so striking, it inspired this post.

The ULA pack was vastly more comfortable in this weight range that the GG Whisper. The simple frame of the Circuit transfered nearly all of the weight to my hips, and Brian Frankle's amazing hip belt easily absorbed the weight. It's possible that I am marginally more tired for having carried the 27 extra ounces of the ULA pack itself, but if so that difference was beyond my capacity to observe.

So I'm wondering, at a base weight (excluding the pack) of around 5 pounds, what is the advantage of going with a SUL pack over a pack like the ULA Circuit?

[John S.]

Base weight does include the pack weight so you cannot be SUL without buying one of those packs unless you are going to skimp on something else important and therefore put yourself at a higher safety risk. It's partly a challenge and partly a marketing strategy IMO.

[Eric Brewer]

As another satisfied owner of a ULA pack, my feeling is that I'd rather be comfortable than to have a somewhat meaningless title (i.e. SUL).

I've only been ultra-lighting for a couple of years, let alone the "S," but I've got about 40 years of backpacking and hiking on my tired feet. In the end, a little heavier but good-fitting pack that WELL supports whatever weight you need to carry is going to trump a slightly lighter pack that hangs like a grocery sack on your back (not to imply that your GG is akin to a grocery sack ;-)

Let your body decide – which one leaves you feeling good at the end of the day?

[Aaron Sorensen]

Hey all,
I agree to the above posts, but only if you're not going UL or even SUL.
Anything over 12-15 pounds is going to make most UL bags fell heavy grocery bagish.

If you are "TRULY" going UL, which is what the bags are designed for, then the UL bags have the advantage.

An UL bag loaded with 2-3 days food and an extra 4-5 lbs for the base is like carrying a heavy pillow and the comfort from the weight and load works.

The most comfortable bag I've ever worn is my home-made 6 ounce, 1650ci pack that is heavily padded and has all the bells and whistles for running. It is the best because it works so good with the gear that goes in it.

Saying you're going UL with a 9 lbs base means that half that weight in the UL bag is going to be hard clunky excess or extra gear that will easily turn those bags in to something you would rather put into a ULA pack.

[EndoftheTrail]

Never underestimate the allure of psychic benefits!

[Brett .]

David, I agree with the need for a belt; I have frameless and beltelss packs, but as a LW, not SUL backpacker, carrying 10lbs TBW day hike, 20 lbs TBW camping, I like a frame to transfer the weight off my shoulders to my hips, where a padded belt, not a nylon strap, distributes it circumfrentially. My dayhike framed/belted pack is a Lafuma Race28 at 1100 grams. And my overnight/camping pack is a framed/belted Granite Gear.

I think of this as a tradeoff between hiking comfort and camping comfort. If you are usually moving, light weight is most comfortable. If you are usually stationary, such as base camping, then comfort in the campsite requires more and heavier items. If someone were OCD and anally retentive enough to graph this, it might look like this.

The 'sweet spot' for me depends on the ratio of hiking to camping for a particular trip, using the lightest available gear to meet each performance requirement.

Similar graphs could be made for safety vs. weight, distance vs. weight, etc..

[Scott Robertson]

Well, it is simple economics. As your weight lowers, the amount of comfort you experience increases less. At a certain point (where marginal comfort meets this curve), maximum comfort is achieved. Of course, as you add weight, less comfort is felt to a point where you are pretty much unable to move.

[Jason Klass]

I agree with the above posts. I say, go with what is most comfortable. It's not like you're carrying 5 extra pounds–the extra weight in this case seems to be justified.

[George Matthews]

Brett,
I like the moving vs stationary comfort tradeoff

Had not ever thought about it this way

Here's my pic of the situation

y axis is increasing weight
x axis is increasing comfort

Decreasing weight increases moving comfort
Increasing weight increases stationary comfort

As the 'moving weight' decreases from your maximum carrying capacity, your incremental comfort

increases. You get less gain in comfort dropping from say 90 lb to 70 lb than dropping from 20 lb to 10

lb. That's why the curve is steep and then flattens out.

As the 'stationary weight' increases from nothing (survival mode) to having everything you could

possibly need (maybe even a kitchen sink), it is flat, but then becomes steep.

The U shape created by the upper parts of both curves shows the increasing and decreasing gains in

comfort during both moving and when stationary.

The bottom of the U is the sweet spot.

[EndoftheTrail]

I like George's analysis of weight vs. stationary and motion comfort. The curvature illustrates better the concept of diminishing returns much more accurately than linear (straight) lines. But I think the mC curve should be the inverse!

Looking at the mC curve and starting on the left, the curve goes down steeply at first, then flattens out. This is saying that at extremely heavy weights, dropping weight a lot will only return minimal increases in comfort. At the right side, however, when weights are already pretty low, dropping little bits more will return significantly more comfort.

To me, the opposite is true. Going left to right, the mC curve should slope downward very slowly at first (almost horizontal), then dropping almost vertically near the end. When load is super heavy, every bit of decrease should feel heavenly. When load is already super light, then further drops should result in little increase in motion comfort, simply because the hiker is already pretty darn comfortable (i.e. way past his or her sweet spot).

In other words, the mC curve should be very roughly the shape of a "7" rather than an "L".

[George Matthews]

Ben, good point. I over exaggerated the shape of the curves.

For example, dropping a couple of lbs from the heaviest load you could carry is still very heavy. Steep – little comfort gain. Also, dropping from 5 to 3 lb is going from very light to very, very light. Again, steep – little gain.

I think the middle area, maybe from <30 to >5, is were there is the most incremental comfort gain. This should be is the flat downward area.

Steep top, flat middle, and steep bottom of curve.

I believe this is why we are spending so much effort here tyring to push the envelope. The comfort gains justify the dollars and research or we would not do it. Unless we're all crazy : )

[EndoftheTrail]

George:

Agree — you are correct! Looks like what we have are two curves roughly forming an "H". The most effective trade off between weight and comfort lies in the middle range, with the "sweet spot" at the intersection of the two curves.

But I think your last paragraph assumes a rationality that isn't always there. We all know people who can hike perfectly fine with 15-20 lbs pack weight (from a physiological viewpoint) — but still, they continue spending money to shave ounces or even fractional ounces — and won't quit even after they've gotten themselves into the realm of SUL (5lbs base weight or less)!!!

What we have here is an entirely different dimension (another curve?) — psychic benefits derived from bragging rights! It bears no relationship whatsoever with physical comfort. Indeed, shaving a small fraction of an ounce off of what is already featherly light pack weight can still produce a benefit (psychic pleasure) that is every bit as intense — if not more so. :)

[George Matthews]

added a psych curve (axis at top of graph)

after our pack wts have the best mix of movement and stationary, we go into the fringe area. the area where we don't care about sC, and drop grams for minimal mC, but get big gains in psych is the lunatic zone : )

[EndoftheTrail]

LOL. We need 3D!

Two questions:

1. Can anything irrational ever be plotted onto a graph? The intensity of any particular psychic benefit probably correlates with the phases of the moon just as much as it does with gear weight or comfort.

2. You and I aside, do you think anybody else is reading any of this? :)

[john flanagan]

Oh yeah – we're reading it! The heights and the depths to which our advocations carry us… LOL

[Sam Haraldson]

I love pointing out to the math threads on BPL to my geek friends that see us backpackers as a bunch of tree-hugging hippies.

[George Matthews]

Got home from work and opened a newly arrived box from GG containing…

1 NightLight Sleeping Pad (Torso length)
1 ThinLight Insulation Pad (thinlight)

Huge gain for me on the p curve. Definitely irrational. I tried them on the floor. Then for a while I rolled and folded as suggested in another BLP thread. Gave serious thought to weighing them and even posting pics, but I'm too tired. Reviews coming soon.

If you put your rational hat on, upon opening it you'd think that someone messed up and sent you a box with packaging material only in it. : )

[Brett .]

George, right, never thought of it like that. I have the same items and it looks like some 'egg-carton' shaped packing foam and a thin sheet of foam for wrapping fragile items. Yet we consider it a 'mattress'.
I found the torso pad to be too bulky to carry. Several liters in volume.. My standard setup therefore is the 180cm Montbell pad set and the 1/8" thinlite. Heavier than closed cell foam-only, but still light at 550grams total for pillow, 120cm pad, 30cm sit pad, and thinlite.

[Brett .]

George, Ben,
Wow, I thought only I was crazy enough to graph this stuff. You are both right, a curved line represents the diminishing returns better than my straight lines.

Edit: Ben, thanks for the input. I will create a better graph..

[EndoftheTrail]

Brett:

I think I agree more with George's graph (although it's getting late here and my head is spinning…). Part of the confusion may lie in the fact that in George's graph, the X axis represents comfort while the Y axis represents weight.

[George Matthews]

now that i'm refreshed after a good night's rest on my packaging (kidding!)

if we flip the graph to emphasize the psych (p curve)
then maybe it better portrays the lunatic fringe (rectangle)

(let me repost the graph – did not work right)

Edit: I was only kidding, both the GG 1/8 and the torso look fantastic and will become an integral part of my Big 4. The price is an excellent value.

[George Matthews]

[Shawn Basil]

OK, folks.

I went to an engineering school (the Naval Academy) where I was a history major (36 hours) with LOTS of engineering, math, and science hours (88 total). The Engineers always used to call us "bull majors". Well in this case, I know enough about bull AND graphs to see who is REALLY slinging some bull.

"If you can't dazzle them with data, baffle 'em with BULL!"

However, I DO appreciate the thought that goes into this. It DOES "sort of" quantify the otherwise intangible aspects of lightweight backpacking. However, the graph doesn't specify the perfect "sweet spot". Therefore I figure I should simply add gradations to the x- and y-axes that specify MY most common load weights as OPTIMAL! Peak Bull achieved! ;-)

[George Matthews]

Shawn busted us : )

At some point in your search for lighter and lighter gear, you enter a realm where you go beyond rational thinking. This trip takes you out of the village and towards the fringe where the lunatics dance nimbly in the moonlight, howling their song.

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