A more complete treatise on ‘mid selection

This post from three years ago has proven to be one of my most popular, all time, and due to the volume of correspondence I receive on it and what I’ve learned since it is due for the an update.  What follows is the text of that post, amended and altered as needed.  There are still some gaps in my experience when it comes to this subject, but a number of most significant open questions or guesses I had back then have been answered definitively since.

img_2087Seek Outside BT-2 and Silvertip, pyramid/tipi hybrids which combine the easy pitch and functional footprint of the former with the weatherproofing of the later.  In the last two years these have become my favorite shelter, ever.

A pyramid shelter is the most versatile shelter for outdoor adventure. There are many reasons to not have a quiver of tarps and tents, and the best one is that having one shelter suitable for all conditions allows you to grab and go. A ‘mid fits this role well. Terminology should be here noted: shelter is used instead of tent for reasons beyond the mere lack of a floor. That a tent is fully enclosed inherently brings with it the expectation that you’ll be consistently insulated from the outside world. This expectation is only realistic in mild conditions, and the separation it promotes from the environment at hand defeats the purpose of multi-day backcountry adventure. As will be discussed below, there are select circumstances where some manner of protection from the ground and/or environment is desirable, however those circumstances are quite limited for most users. 90% of user objections to non-fully enclosed shelters are mental problems only, and those folks owe it themselves to get over them.  When additional protection is needed, there is a lot to be said for it being modular, and removable.  Using the same tool for summer bug pressure and late fall condensation issues, for example, doesn’t make much sense from a performance and weight/benefit perspective.

img_2067The Seek Outside Redcliff, a legit 4-6 person mid-pi I can stand up in, whose canopy alone weighs over 3 pounds.  Small kids are an instance when extra space, and the containment of a nest, can be close to necessities.

The first consideration in mid selection is size. Capacity is a good starting point here, but just as important is a pragmatic assessment of space per person desired and the 3D floorplan of the mid in question. The Black Diamond Megalight is a good example. The company claims a width of 86 inches and a height of 57. When pitched to the ground, the actual width is 104 inches and the actual height is 68 inches. Due to the slope of the walls, much of that 104 inches is not useable for human habitation, but it is useable for gear. In practice, there is sleeping room only for four in the Megalight. Three is a sustainable capacity for extended trips in varied weather, while two is very comfortable and allows for plentiful gear organization, cooking, and even a small wood stove. It’s overkill for one, but light enough to constitute reasonable luxury. Mid capacity requires critical thinking, as floor dimensions do not tell the whole story.

Size to occupant ratio is also highly relevant when planning how to manage condensation.  The particulars and myriad, but the short version of this question is that the more people are in a given volume of enclosed air, the more condensation there will be.  Two people in the Silvertip could, for example, have horrendous condensation while right next door two people in the Redcliff would not.

8YFdPio3S323s9tLUcQ3XrWHtNKwcuNniYtjwZJJIBvm5iYfh8cg1PovG3op7pMIboNiL0DCq3m1ztUwJ6ZOEPchGZPd2ljs5t9lINCVBNpbbY365OPp9yrTWdpEzwyH68-qW-Ss0i3jxwTEXx49MzUhOm8kTq1yFeRqAPaM256ophGkSAw6UVwtLe2zK84Pc0QZ8ngtFvm4pYcm-PDP7wfwNIieVw3wZEThe Sierra Designs High Route, a unique take on the two-pole mid, and a design which compromises weather resistance in order to maximize useable space for a given footprint, something which also facilitates good venting.  Andrew Skurka photo.

Mids can be usefully separated into three categories: unipolar rectangular mids (which include square mids), bi-polar rectangular mids, and tipis. Each has virtues and downsides, and these are the second criterion after capacity which should drive mid selection.

Unipolar rectangular mids are the classic version, and remain the most common and popular for good reason. There’s quite a bit of variation in size and height, which not only determines capacity but also performance. For example, imagine the Megalight with a lower center height. Lower angled walls would provide for better wind shedding, but reduce functional space as well as the ability of the mid to shed snow.  The MLD Trailstar is the extreme example of this. A higher peak height would steepen the walls, causing an increase in weight (due to extra fabric, and more relevantly a thicker and stronger center pole) and improved snow shedding.  Tall mids can suffer from poorer performance in bad weather due to extra surface area, though I think this is a minute factor which can be designed around. Smaller mids, the MLD Duomid and Solomids being the most well known example, attempt to win more functional space with minimal material and center height by being very rectangular. This does the job, but at the expense of creating unequal surface area on the sides. All things being equal, such mids do less well in wind when broad side.

IMG_3397The MLD Solomid (non-XL), which is an exceptionally strong shelter in strong wind, due mostly to its very low profile.  The cost for that is limited headroom.

Bipolar mids attempt to take this expansion of functional floor space further by using two poles rather than one. What this achieves, in shelters like the Golite Shangrila 2 above, is a useable mid-height approaching that of a unipolar mid while having a much smaller footprint. The extended, steep ridgeline of such shelters also tends to shed snow well, at the expense of considerably weakened wind resistance when broad side. Most of these mids are not simple rectangles. The Golite Shangrila 2 and Black Diamond Betalight are both hexagons, with the middle being wider than the ends, which provides more interior space and improves the slickness against the wind.  The Sierra Designs High Route has by contrast a rectangular footprint, which improves on useable interior space even further, at the expense of vertical sidewalls, which as this video shows are merely adequate in strong winds.  I’ve largely given up on these designs; when push comes to shove in truly strong winds, they seem to fall flat.  Symmetry is not just an aesthetic consideration.

Wind resistance is achieved by having small facets for wind to grab, and this being the case, the slickest shelter is the one which is most curved (a fact which helps explain the popularity of tunnel tents for arctic and montane expeditions). Tipis are mids which try to take this to an extreme by being conical.  This is an effective solution, but comes with the expense of weight (for a given space) and complexity. A round or oval floor plan is a bit less efficient than a square or rectangular one, but a more serious objection is the less intuitive pitch a round or oval footprint necessitates.  It is illustrative to contrast the Redcliff, above, with a six-person tipi, which provides comparable floor space.  The first time I pitched the Redcliff I had the “help” of Little Bear trying to stomp all over the canopy, and still got it dead on the first go, which took about 2.5 minutes.  The six-person footprint is not so intuitive, and on my first try took me about five times as long. However, there is no arguing with the strength of a round tipi, from all five directions, which helps explain their popularity with base campers, horse packers, fly in hunters, and other for whom setup time is within reason not a concern.  They’re also beautiful structures, which explains why they play so well on instagram.

IMG_2623
The Seek Outside Little Bug Out, 80% mid, 20% tipi, the subtleties of whose design I discussed here.

There is a class of hybrid mid-pis, who use five or six sides to gain increased wind resistance over standard square mids. The chief cost, as with tipis, is in the ease of pitching.  In the case of our (Seek Outside) mids, I’ve come to regard the extra cost of needing six (Silvertip) to eight (Cimarron, Redcliff) stakes as the functional minimum, rather than four, to be a worthy tradeoff for the increased weatherproofing.  While they still possess the inherent limitations of mids, they are otherwise perfect.  A solipsistic statement, perhaps, but I didn’t take the job just because, either.

The limitations of mids mostly have to do with condensation, which in turn mostly has to do with their inherently limited ability to vent well when it is needed most.  Using cordage to elevate the edge of a mid a few inches to a foot above the ground can help quite a bit, but in those occasions when condensation tends to be worst (cool, humid, still, rainy nights) doing this is not always practical.  Mids are a great quiver of one because they’re light, strong, and quick to pitch, but more severe weather (esp wind) is their forte.  Forest dwellers who see humidity and rain often, and exposed wind seldom, are the leading candidates for a shelter other than a mid.  The Tensegrity is a good example, it being the opposite of mid-shaped.  We’ve found it to vent and control condensation well, but no matter how tight the pitch be vulnerable to lots of movement and noise in moderate winds, especially when those winds come from the side.  Thankfully it’s generally easy to look at, for example, the Tensegrity and the Silvertip, and for a given trip pick which one will be best.

So go get yourself a good mid. Go use it. Have fun.

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5 Responses to A more complete treatise on ‘mid selection

  1. fedster9 says:

    The ignorant would like to ask — what is this ‘mid’ term meant to mean? I do get ‘pi’ is ridiculous for pyramid, but mid? As a by the way, if making backpacking more accessible to those who are not time and money rich hipsters is really part of anybody’s plan, all this jargon needs redesigning. Plain English does work too. Feeling unremarkably grumpy, as you might notice.

    PS great looking tents btw

  2. Dave, first of all, welcome to the neighborhood. I would love to meet up with you guys as fellow sewers and makers. (Bedrock Bags from Durango here) Also, thanks for the insight on mids. I have a Megalight now but would love to move to an American made product with superior design and it looks like SO has that to offer. However, I wonder if you could comment on something I have experienced with mids in the desert southwest. I am often in sand or on bare rock and while I love the space, shelter and lack of weight a mid has to offer they are, in my experience, difficult to rig taught in the aforementioned conditions. Lot’s of rocks or dead men work but time and resource consuming. Am I just bitching too much?

    • DaveC says:

      Definitely an issue. Freestanding tents can definitely have an edge there; you still need anchors for wind, but you can be a bit lazier about it for sure.

  3. Do you find the nest useful or necessary on the Silvertip with the sod skirt and screen door? Seeing how the nest doubles the weight it would be nice to avoid it. I’ve never used a mid before, but just borrowed a modified Megalite with no-see-um mesh sewn around the base to try out. I’m hoping to spend a lot of time this year above 10,000ft in the Sierra and cover more miles, hoping a mid will help with these goals.

    • DaveC says:

      We no longer make a Silvertip nest because it just doesn’t make much sense with a light shelter. Sod skirt and screens are good to go up to really nasty bug pressure, at which point that nest would be nice. But 99.5% of the time no need.

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