I have been meaning to get this off my chest for some time now. I started a discussion about this on BPL a while ago, but it didn't really go anywhere or catch on; so here is another attempt, this time with more substance--and I hope that the idea takes off (even if it is another shot in the dark).
There is not really a consensus agreement on what defines Ultralight backpacking and its different variations. Wikipedia's entry on the subject currently states:
"The terms light and ultralight commonly refer to base pack weights below 20 pounds (9.1 kg) and 10 pounds (4.5 kg) respectively. Traditional backpacking often results in base pack weights above 30 pounds (14 kg), and sometimes up to 60 pounds (27 kg) or more. Enthusiasts of ultralight backpacking sometimes attempt super-ultralight backpacking (SUL) in which the base pack weight is below 5 pounds (2.3 kg) and extreme-ultralight backpacking (XUL) in which the base pack weight is below 3 pounds (1.4 kg)."
Yet the above quote from the text offers no citation, and the word "commonly" is perhaps problematic. Take for instance John Abela's thoughts on the matter, the author of a popular blog among UL enthusiasts, who defines UL as a base pack weight of 5.4kg/12lbs and under. A 20% increase in weight is a significant difference, especially for a group of people so concerned/obsessed with every little bit of weight. Abela doesn't explain why he adds two pounds to the "common" definition of UL, and I would have liked to know why he did so, even if all these numbers are admittedly arbitrary.
Then there is Ryan Jordan of BPL fame, who in a text that accompanies a video series on SUL backpacking writes:
"The purpose of this series is to explore (at least on the surface) - the art of “SuperUltralight” (SUL) backpacking - considered by most to be the practice of backpacking with a base weight of less than five pounds.
However, I won’t necessarily hold to that performance standard (weight) or extreme (five pounds) in this series. Instead, I’m hoping to promote a more reasonable definition of “SUL” that simply embodies what we do at the very extremes of ultralight backpacking in terms of weight, simplicity, and compactness of our gear."
So for Jordan SUL is more of a state of mind rather than strict adherence to the general consensus of what weight defines SUL. The gear list he provides in said text is under 2.3kg/5lbs, but he notes that it is different from the gear used in the video, which includes a small hand axe (368g/13oz). His listed base weight plus the axe would put him at 2.4kg/5.4lbs, which would make it UL according to some--but the whole point of his efforts are to challenge the conventions and definitions, naturally. I think this is actually a good and worthwhile endeavor, in spite of my differences with Jordan regarding other aspects of how he contributes to the backpacking community.
Though that being said--and I can't stress enough how much I value questioning, re-evaluating, and re-defining ideas--I also think there is great value in having consistent standards, definitions and terms. Having generally agreed upon definitions and a consensus of terms helps a community to have a fluid and productive discourse. Not to mention that having a general consensus would be helpful for people new or unfamiliar with UL backpacking, and also to help have some kind of universal standards to work with.
Which brings me to my next point. I personally think that if there are standards of weight used in defining a term, it ought to be metric, as that's the weight system the whole world uses--except for the USA, Liberia, and Burma. This is not a very popular suggestion, however, as I have gathered from the forum at BPL, as most UL backpackers there (and in general) seem to be American. But there are communities of Ultralight backpackers all over the world, and forums on the subject such as BPL and Reddit's /r/ultralight have international contributors that prove this rather uncontroversial claim.
Say nothing, of course, of the more logical, practical application of grams over ounces and kilos over pounds, in that metric weight is a consistent set of units. This image perhaps demonstrates this point best, but in backpacking terms, counting say 5g for a small Cuben stuff sack, is easier than 0.17637oz or 0.0110231lbs on a gear list. Or a 515g backpack is just simpler to write out and do math with than 18.1661oz or 1.13538lbs.
All this being said, here is how I personally define the wonderful world of arbitrary UL weight definitions, and think others should too:
Around 5kg and under BPW = UL
Around 5kg and under BPW *plus* CW = VUL
Around 2.5kg and under BPW = SUL
Around 2.5kg and under BPW *plus* CW = XUL
UL = Ultralight (duh), VUL = Very Ultralight (I just recently came up with this myself), SUL = Super Ultralight, and XUL = Extreme Ultralight. BPW = base pack weight, and CW = clothing (including any gear in your pockets) worn.
Just like ten, five is a nice, round number. 5kg as the basis of UL also represents with current technology a goal that is relatively easy and arguably affordable to put together, and to use in a variety of conditions (i.e. 3 season) for the activity of backpacking. I also personally felt a big difference in the experience once my base weight went below 5kg as I cut my pack weight down from over 10kg as a traditional backpacker, and halving that number only further accentuated the experience.
It's not a magic number, of course, but what I and others have observed is a good approximation of when things significantly improve--which is probably why the "common" idea of UL hovers around 4.5kg/10lbs, which is close to my suggestion. For example, I was able to hike roughly 10-15km before becoming exhausted with over 10kg base weight in the past; but under 5kg I am able to do around 20-25km (and sometimes more) before getting tired, and under 2.5kg can do the same and more with relative ease. Anecdotal, sure, but I have read of many others that have made the transition from traditional backpacking to UL and SUL report similar results, and often exceed the distances I hike without much issue. Many regulars at BPL claim to routinely go 20 and more miles (32+km) a day.
I don't define or discuss SXUL (Super Extreme Ultralight, that Abela forwards as a base pack weight of under 900g/2lbs), because it is so far out in the margins of backpacking at this point in time--with all due respect to Abela and others that might practice SXUL--it simply does not merit much consideration or thought to the grand majority of ultralight backpackers. SXUL's application is so narrow and specialized that there's just not much to examine, and it's only going to be relevant to perhaps a handful of people in the world. Plus it just has to stop somewhere. Or should we entertain the idea and discussion of DSXUL (Double Super Extreme Ultralight), base pack weight of under 450g/1lb, and so on?
For people that only care about pack weight and/or want to keep in simple (or cheat and stuff their hiking pants full of gear), UL and SUL are the only two terms that matter. But for the gram geeks that also take everything else they carry aside from their backpack into consideration, my VUL and XUL definitions can be helpful in evaluating the total sum of unchanging stuff that goes with them on their trips. Metric weights also add a bit more weight--about 500g/1lb to UL and 225g/.5lb to SUL--to the Wikipedia and/or "common" concept of what Ultralight weight standards mean, which a lot of people that are slightly over those marks might be happy about.
And what of this whole "common" set that Wikipedia documents and the people and community that accept and use these terms? I propose the community collectively decides. If not my suggestions, then another set of definitions and terms, so long as the majority agree to them to make the most people happy--a democratic selection of definitions and terms. I am willing to accept, endorse, and use whatever set wins a clear consensus. Of course I think my idea is best, but would gladly use another one just for the sake of clarity and consistency.
Obviously people can and will reject whatever set wins, or any other definition they don't agree with or like. And there may even be a revolt to change things in the future, or maybe this whole thing goes unnoticed and blows over. I figure it's still worth a shot, if anything for an amusing waste of time, and it goes without saying that people should still use whatever terms they want in spite of the results of the vote. All I am asking for is something that resembles what the majority of people understand as what defines ultralight backpacking and its variations.
So I say let's vote. Below is a simple poll I created that tracks IP addresses and only allows one vote per. The poll is open for a month to allow for discussion and debate on the topic. Once the poll is over, the winning set an be added to the Wikipedia entry on Ultralight backpacking and its definitions and terms. The poll can be used as a citation to give support for a general consensus that confirms things.
The four options I put in the poll I think speak for themselves, especially if you've read this article and all the other links above. The only one that might need a bit of clarification is the straight "metric set," which is just an attempt at a rough metric equivalent to the "common" set. I'm not aware of any other forwarded sets of definitions and terms of much significance, but if I've somehow missed one I'd be happy to create a new poll and do the vote again. But right now I feel these four options are the best we have to work with at the moment.
Overly ambitious? Maybe. Biased? Well, yeah--of course I think my idea is the best one. At least I give what I think is a good argument in favor of my idea--at the very least you have to admit I've done my homework and given all this a lot of thought and consideration. But all that aside, perhaps this vote will finally give a definitive answer to the general question, "What is Ultralight backpacking?" and put this issue to rest. Being able to cite an actual, real general consensus is not only cool but useful too. Granted, this is not 100% scientific or anything, but it's a good approximation of the community's opinion on the matter if enough people vote--and especially strong if a lot of people vote.
Now go vote, and feel free to share this article or the poll!
*Note - Edited 31/12/2103 around 1pm my time. Just fixed some typos and added a few minor details for cohesion and clarity.