Pyramid shelters have become inexorably associated with modern “ultralight” backcountry travel.  For me they’re a staple, one I’ve discussed extensively (most recently and completely here), that for many conditions provides a light and simple no-thought solution to whatever weather might come along.  That said, I do think the utility of mids has been overstated.  Their chief virtue is a shape which deals well with both wind and precipitation without requiring too heavy a support structure.  Adding ventilation is at best problematic, and at worst a waste of time and weight.  Trips which don’t require exceptional weather shedding, and favor ventilation (often in concert with bug protection) are in the majority during the warmer six months of the year in Montana, and for an even greater period of time elsewhere.  Having the Tensegrity 2 (which is both sadly discontinued, and still available on clearance) in our quiver has been nice for those trips, and relieved much soggy, claustrophobic bugginess which in years past mids have provided as a mid-summer blessing.

What then makes for an ideal mid shelter?  If mids are good for snow and rain, and most especially for strong winds, it makes sense to maximize those attributes.  Design features which promote wind and snow shedding are worth the weight, anything else has at best a marginal case for existence.

But what are these features, and which attributes and dimensions make a ‘mid work best?

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My favorite mid features, or at least the simplest one to love, are the sod skirt and abundant ground level stake points on the Seek Outside BT2 (red shelter shown above, now slightly modified as the Silvertip).  Having a windy weather specialist that has a big gap along the hem to scope in wind and freeze the occupants has never made any sense to me, and was the sole reason I sold my MLD Trailstar many years ago, and a major reason I sold my MLD Solomid more recently.  The small sod skirt or snow flap arrangement on the BT2 solves this problem definitively.  Even a mid like the BD Megalight (above) which has fairly mild caternary curve along the bottom edges, still leaks a lot of wind unless you carry bury the gap in snow.  Today I find it hard to imagine why I’d ever want a mid without a bottom flap.

That the BT2 has 12 ground level stake points, closer than 3 feet together, both helps seal wind out and adds considerably to the overall pitch strength.  Mids resist wind, rain, and snow by having lots of tension between the apex (supported by the pole) and the hem, supported by stakes.  Unless you bought an Aliexpress special made from shit fabric, your mid will almost certainly fail in one of two ways: high winds and snow will snap your trekking pole, or will pull the stakes out.  The first problem can be addressed with burly trekking poles or a shelter specific pole, the latter by using the right stakes for the soil in question and by having a shelter which lets you use plenty of them.  Mid level guy points are useful, especially for minimizing panel deflection when design constraints put that area at risk, but ground level stake points are the foundation of a solid pitch, and of a solid design.  Square mids like the Megalight, which generally have nearly 9 foot sides and only one guy point at halfway could certainly do with two instead.  12 total for a mid of this size is emphatically not overkill.  The LBO pictured below has only 10, which makes for relatively big spans between stakes on the wider rear portion.  I wouldn’t object to an additional 4 in this spot.

R0023009R0000107R0012840Seek Outside LBO with 3 piece vestibule.  Hopefully these three photos, combined with the chart below, show the somewhat complex shape which I’ve found to perform so well in bad weather.

Sewing flaps and a bunch of guy loops on is easy.  So what about dimensions?   Specifically, what combination of height, length and width make for the strongest overall mid, while still maintaining useable space?

The chart below details a range of mids I’ve used a decent bit in the field, omitting the BT2 (which is no longer made) and including the Supermid (which I’ve never owned, but is something of a touchstone in the genre).  All of the listed dimensions have either been confirmed by me personally, or in the case of the Supermid taken from numbers Chris Wallace put in his BPL review a number of years ago.  My thesis before beginning this investigation was that lower angles would be characteristic of shelters which shed wind well, snow less well, and had less than ideal liveable space.  The Solomid and Cimarron fit into this category.  Higher angle walls would be characteristic of both good wind and good snow shedding, but would be associated with struggles getting stakes to stay put in looser soils, something I struggled with early this year with the SO 4 man tipi.

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As the numbers show, things are not so simple.  I was not surprised that the long wall of the Solomid was the lowest angle in the test.  I sold that shelter because it didn’t take much snow to put the wall down on my face.  I was a bit surprised that the long wall of the Cimarron was essentially the same angle, something which confirms my suspicion that this mid desperately needs to be 6+ inches taller, for both space and snow shedding purposes.  (It is worth noting that the specs for the LBO and especially Cimarron are deceptive, as these shelters are modified octagons rather than rectangles, and thus longer midpoint to midpoint than corner to corner.  I used the former figure as I think it tells more about bad weather performance.)  I was also surprised that the 4 man did not have steeper angles, and that the short axis of the LBO shares almost the same figure with both the Megalight and Supermid (53 degrees, also the wall angle of the BT2).

r0021562img_20874 man tipi, at top, with BT2 and Silvertip, below.

These numbers, and my experience of how they play out in the field, show that there is a tension between specific design elements when making a mid.  Steeper walls are better, within the realm of practicality.  They shed all weather better, and provide for more useable interior space.  Taking this approach too far adds weight, both in more canopy material and especially in a much heavier pole.  Modest winds broke a trekking pole used to pitch the 4 man this past winter, one that in the BT2 and LBO had weathered some of the worst weather I’ve ever witnessed.  I also suspect, but cannot quantify, that longer fabric spans require more staking power, and put more stress on even large and well placed stakes.  On that same trip I had a hard time getting the 4 man anchored well enough, in loose desert soil, to hold up to the canopy tension I wanted.  At the time I assumed it was due to a steeper wall angle, but that is obviously not the case, given that I’ve gotten every other shelter here discussed to work just fine in practically identical circumstances, and was using big premium stakes with the 4 man.

I suspect that making a mid much taller than 72 inches quickly runs into exponentially diminishing returns.

Another prominent issue is shape.  Circular mids, aka tipis like the 4 man and BT2, shed wind demonstrably better than square or rectangular mids.  The lack of long edges along the group also fights snow build up and wall collapse quite effectively.  The disadvantage is in pitch speed, with the time involved for the 4 man and something like the Megalight being 3-4 times greater, as well as in effective interior space.  The Silvertip, with its almost symmetrical hex shape, is a good compromise.  Such a shape allows the virtual box of occupied space to be longer than it is wide, without creating big flat panels to catch wind and snow.

IMG_2623IMG_3397The LBO after surviving the nastiest storm I’ve ever slept well through, the the Solomid after a night I spent only laying north to keep the wind out of my sleeping bag.

So if the dimensions of a good backpackable mid exist within a relatively narrow range, and the other major keys to success involve lots of stake points and appropriate fabric orientation when cut for the panels (an item for another day), what are the things which can be appropriately left off a good mid?  In short, almost everything else.  You need a door, but for shelters of this size I’ve concluded that two doors is a luxury I can do without.  For something like the LBO, for instance, I’d choose to go with a single end zip like the HMG Ultamid 2.  I would stay with the non-urethene #8 zips, and a good zipper flap with plenty of velcro to keep flapping to a minimum.  The massive vent formed by the beak of the LBO is the only one I’ve used which is remotely worth having, and I could easily manage without any vent at all.  Given that they’re all at least fairly fiddly to sew the cost savings involved is reason enough for vents to be left off mids.

A lot of the final weight savings on a mid ought to come down to appropriate materials selection.  Grosgrain ribbon for stake points, for instance, is more than strong enough.  5/8″ grosgrain is far stronger than even the very best 30D silnylon.  On the other hand proper webbing might be justified in this application for the enhanced abrasion resistance.  The material used to reinforce tieouts should also be carefully chosen.  Fabric weight much beyond that of the canopy itself is probably not necessary, and if the fabric chosen for the reinforcement stretches much less than the main fabric you might create one problem in the process of solving another.  Or just pull a Kifaru a tack that shit straight on to an extra wide rolled hem, because that is a really good idea.

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But what about condensation?  Plenty of conditions for which mids are ideally suited, such as sustained cool rain or deep snowy cold, breed severe condensation.  Venting has generally been the answer, but as discussed almost never works very well.  Condensation is worst when air movement is modest, and anything short of massive vents only work well when the wind is blowing to help them along.

The real answer is to have a solid fabric, breathable liner, as pictured above and discussed here.  I’ve kept the liner permanently attached to my LBO since I made it, and it helped keep condensation to a minimumon every hunting trip I took this fall, all of which had moderate to severe condensation potential.  6-8 ounces of liner is massively better than 1-2 ounces of vent, and can be left behind if desired.

The sad conclusion of all this?  No one makes what I want, so at some point this winter I’ll be doing what I promised myself I wouldn’t, ever; buying a bunch of sil and diving back into the slippery process of cutting and sewing precision curves.