MLD DuoMid vs TT Rainbow: wind stability

[John Carter]

Ron at MLD has announced he will be making an inner bug nest for the DuoMid. A followup email with Ron estimates it will come in at 12-14oz. This puts the silnylon DuoMid at 27-29oz with inner. My TT Rainbow weighs 30.8oz (tent & poles). With a trekking pole extender on the DuoMid, that would put the two shelters at nearly identical weights.

So, which one do you think is more wind stable?

This is a rather loaded question, so let me unpack it a little. First, let's make a few assumptions: 1) the DuoMid is being held up by a CF trekking pole with extender, and 2) the Rainbow has a pair of CF trekking poles in the cross strut grommets, with the mid-height arch sleeve pullouts secured in a V-shaped guyout configuration.

Let me point out that the answer is not as easy as it may seem. For example, the pyramid shape of the DuoMid is the classic wind-resistant shape. But it relies solely on a single trekking pole. Reviewers have reported in the BPL forums of their aluminum poles being bent in high winds in their GoLite Hex 3 / Shangri-La 3. Presumably there is a wind speed strong enough to catastrophically snap a CF trekking pole in a pyramid design. The DuoMid also has no side pullouts (arguably not needed, but the fact remains), and the DuoMid is taller.

The Rainbow's obvious weakness is the 12' arch pole, prone to snapping. But having set up a Rainbow with dual trekking poles at the cross strut and securing the mid-height arch sleeve, I can testify that it would take a seriously strong wind to bend the 12' pole hard enough to get it to snap. Would the DuoMid pole still be standing in winds this strong? Plus, the Rainbow is able to distribute the pressure between two trekking poles and the arch pole, whereas all of the lateral wind force must be absorbed by the single pole of the DuoMid.

See how the answer becomes less obvious?

Lastly, I would like to state that I believe both shelters are excellent choices, and I don't think this thread should degenerate into which tent is better. Both have many strengths and very few weaknesses, and one should let the features they prefer guide their decision. Therefore I would like to limit this thread to comparing the wind resistance, which is just one of many comparisons. I have chosen these two tents because they appear to share the following features above other tents: best-in-class wind resistance, excellent solo interior head room, can comfortably accommodate a 2nd person, fully enclosed from bugs and weather, and sub 2 lbs.

EDIT: I should note that the DuoMid has an apex loop, so one could add guyline, even dual V-shaped guyline, from the top of the DuoMid to stakes a few feet away in the direction of the wind. Would this significanly reduce stress on the center pole to give the DuoMid the wind advantage?

EDIT 2: The DuoMid now has side pullouts on all four sides. Also, the DuoMid InnerNet is 82" long; not long enough for a 6'2" person on an inflatable pad unless he or she sleeps on the diagonal. It means this is just a solo shelter for taller hikers. Then again, the Rainbow is narrower than the DuoMid, so it is a tight squeeze for two as well. Both would fit two in an emergency, but neither would be very comfortable. Lastly, the Rainbow should offer more percieved inerior space with it's steep walls and lack of center pole. But now I'm drifting into non wind-related comparisons…

[Jonathan Ryan]

hey John,
where did you hear about the bug net for the Duomid?

[John Carter]

From this forum thread:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=18204&skip_to_post=140072#140072

Ron Bell says the following:

"Spoiler…We plan on a net insert for the Duomid in March."

[Diplomatic Mike]

I too e-mailed Ron after his post about the nest. He said the nest will have a 5" bathtub floor. I asked about outer tie-outs, and the side opposite the door will have a mid-panel tie-out. Adding a guy-line from the apex loop in the opposite direction will make this a very stable shelter in my opinion.
I'll be at the front of the line. :)

[John Carter]

Looks like I was incorrect with some of my information about the DuoMid. The DuoMid does in fact have a mid-height panel tieout on the rear panel. Presumably the side panels are not wide enough to need tieouts, and the front panel has a reinforcing zipper.

In either case, both Ron and Henry would customize either shelter with added guyouts if requested.

[Jonathon Rogers]

DuoMid plus net insert and 5" bathtub floor at 30oz? This looks like it will be my new 4 season shelter…why even bother with something like a Big Agnes Fly Creek UL1 at the same weight when you get far superior winter performance from the DuoMid!?

I think this will even work well in summer conditions in the humid Southeast given its versatility in pitching.

[John Carter]

Add a TT Rainbow-style awning, and use your partner's 2nd set of trekking poles to create a nice porch. Get ready for 3-month wait times once this thing takes off. =) (No offense to Ron Bell; this is typical of build-to-order companies).

[Harlan Bruce]

All four sides of my recently-purchased DuoMid have mid-height tieouts.

[Andy Howell]

All four sides have a mid height tie out.

Reports suggest that the Duo Mid is rock solid in high wind in pegged out using the four side guy ropes.

Ron tells me that the CUben version is just as tough as the sinylon. The zippers on the cuben are less robust but with care these sholud not present a problem.

[John Carter]

Indeed, all four sides now have pullouts. At the time I started the thread there were not pullouts on all 4 sides, per a conversation I had with Ron. It's nice to see he added them; I have updated the original post to reflect this change.

[Richard Nisley]

My experience with the Duo Mid (mid guy outs version) is that it is rock solid in high winds. It has become my go to shelter.

For winter use, it would be nice if Ron Bell offered two all fabric inner options in addition to the recently announced mesh inner. The first all fabric option would just be a replacement for the mesh inner. The second fabric option would be a hood that slips over the top of the mesh version for versatility.

[Andy Howell]

I had the cuben Duomid out in a horrendous coastal storm on Friday night and more or less reassured myself that this is a bombproof piece of kit. The mid panel guy points are very useful.

The most important things about pitching is to get the pole height right. Too low and its very difficult to tension the material properly.

[. .]

+1 on that request!

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