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Most Breathable Bivy?
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Nathan Watts
(7sport) - MLife
MLD EVent Bivy on 03/04/2013 14:19:31 MST Print View

I use a waterproof breathable bivy made by MLD out of eVent and Cuben with a mesh window. I don't use a tarp though. It weighs something like 12 ounces.

If I was to use a tarp I would to ably just use some type of mesh netting for bug protection since your tarp, your bag, and your Tyvek ground sheet should give you protection from the elements. I prefer to use a tent instead of all this though. It's lighter and less complicated. Maybe I'd think differently about tarps if we didn't have bugs around here.

Edit to note that I don't use my bivy in the tent. Usually the bivy for light and fast overnighters. The tent for everything else

Edited by 7sport on 03/04/2013 14:21:06 MST.

Max Dilthey
(mdilthey) - M

State of Research on 03/04/2013 14:24:46 MST Print View

Thanks for the info, guys. here's what I'm thinking.

Perhaps I'm going to end up going for the Trailstar full over the Trailstar Mini, but I'm a side sleeper that doesn't mind curling up. It would bother me to not be able to stretch out my legs inside a bivy, but in a tent it wouldn't bug me at all. I've slept in some confined spaces before. I'm generally a very, very easy sleeper and nothing wakes me up.

I'm going to stray away from full bug bivy's. Maybe I'll own one in the future, but not for this purpose. The "fun" (clearly Type 2) of going out in a big thunderstorm or early fall hurricane and sleeping in a field or clearing is facing the elements and winning, NOT getting wet. I think the Tarp does 99% of the job, but just in case I can't get a good pitch because of my site, or in case water saturates around me, I want good coverage from my bivy above and below. I don't need sustained exposure waterproofness, but I can be talked into eVent, as my understanding is that this is the best WPB fabric since it has pores.

Phew. Getting carpal tunnel over here.

I'm looking at the bags from integral Designs, but I think only the Spartan Bivy has bug netting. If someone knows otherwise, let me know.

Otherwise, I'm looking at the MLD Superlight Bivy at 7.5oz, but I don't know how waterproof the silnylon bottom is and I don't know what "Endurance" fabric has in the way of comparative strengths and weaknesses.

I have yet to find an e-Vent bivy with a bugnet. If you know of one, let me know! If I missed it in previous reccomendations, I might catch it in a minute...

Thanks for the help!

Steven McAllister
(brooklynkayak) - MLife

Locale: Atlantic North East
Bug Bivy on 03/04/2013 15:23:30 MST Print View

Regarding waterproof, water resistant or mesh top.

Be aware that the mesh top style will be much more comfortable for 3 season use. Full coverage bivys are hot, stuffy and can trap condensation.

If a full mesh top scares you, maybe the SMD Meteor? But even that can be too stuffy in the summer.

I find that under a full coverage tarp, a full coverage bivy is overkill.

A mesh top/bug net/bivy will be much more usable.
There are a lot of good bug nets out there that have bathtub floors to protect from wet ground and splash.

David Chenault
(DaveC) - BPL Staff - F

Locale: Crown of the Continent
re: bivy questions on 03/04/2013 15:42:20 MST Print View

First point: get the full size Trailstar. I'm a hair under 6 feet and the fully was just long enough on some occasions.

Second point: define your use. You will not need a bivy for rain protection in a Trailstar. A tarp is another question. If you want bug protection, a groundsheet and the Gossamer Gear bug canopy will be fine.

Third point: If you're out in 30+ mph winds in the Trailstar you might want a bivy or overbag for wind protection if it's chilly. The cat-cut edges make it pretty hard to seel the side unless you have snow to work with.

Fourth point: a WPB floor will make a pretty big difference in breathability compared to a sil or cuben floor and the same top material.

Fifth: Pertex is a company which makes many fabrics. Quantum, often used in bivy tops, is pretty darn breathable.

Max Dilthey
(mdilthey) - M

Stop Recommending Bugnets, please on 03/04/2013 16:04:14 MST Print View

I don't think you guys are understanding me, or reading my posts. Which is fine, I mean, I talk alot, I'd ignore me too!

I'm specifically buying this setup for conditions where my hammock is unusable due to high winds, intense rain, and the risk of falling branches. I am buying this for cold, wet, windy storms in the middle of clearings.


I DO want full coverage and NOT a bugnet, because of the wind drafts and the associated spindrift and spray. Thank you for the suggestion of a full-coverage bugnet, but that is something I don't need help deciding on. If I want one of those I'll get them but it's irrelevant.

To the point of my OP, please feel free to recommend full-coverage bivy's made of WRB or WPB fabrics from reputable manufacturers. I'd love to hear of your experiences with condensation.


just Justin Whitson
Re: re: bivy questions on 03/04/2013 16:17:27 MST Print View

Hi Max,

It's pretty easy to make bivies, and if you can't sew or don't have a sewing machine there are tapes and glues that work decently.

If i was making a UL bivy for the conditions you are describing, i would probably use Momentum 90, Pertex Quantum, Nobull, or similar fabric to these.

And while you don't like the bug netting suggestions, personally i would at least make the middle of the top layer out of that to increase breathability. Keep the feet to knees, and upper shoulders to head area out of the first mentioned type fabric for adequate, extra rain protection.

Bottom can be Tyvek homewrap if you want to keep costs and condensation down. But then again, you said price doesn't matter, so sure go with eVent.

Edited by ArcturusBear on 03/04/2013 16:21:51 MST.

Stephen M
(stephenm) - MLife

Locale: The Deep Frreze
Re: Stop Recommending Bugnets, please on 03/04/2013 16:19:37 MST Print View


In those conditions I would be using a Trailstar with a fully Wpb Bivy if below treeline, if above treeline I would pack a proper tent.

A Bivy with a Dwr top will do also.

Alex H
(abhitt) - MLife

Locale: southern appalachians or desert SW
Re: re: bivy questions on 03/04/2013 16:48:54 MST Print View

So Max, you probably have seen my piece on bivy's and condensation

There are a number of references at the bottom including on discussing fabrics (#'s 9-11)

The bottom line as has been suggested above is the best bet is an all event bivy (the ID all event bag now discontinued). Even though it may appear that there are new offerings this spring there is still no holy grail fabric or design wise. Dave Miles tyvek and polypore bivies appear to be very breathable but not very light.

You are on the right track with the ID bivy's and maybe something from RAB with event. I am glad that $ are no concern. The MLD cuben/event is the lightest and maybe fit your needs most. Ron could probably put more mesh in around your head if you want. But I now see that it is not even on the website anymore, even at $300+ for a bivy.

There was great discussion of bivy's and condensation in difficult conditions started by David Ure but I don't have it bookmarked.

Jeffs Eleven
(WoodenWizard) - F

Locale: Greater Mt Tabor
Re: Re: re: bivy questions on 03/04/2013 16:51:38 MST Print View

Dave U.s thread

Alex H
(abhitt) - MLife

Locale: southern appalachians or desert SW
Re: Re: Re: re: bivy questions on 03/04/2013 16:59:47 MST Print View

Thanks Jeffs, that was the thread.

Nathan Watts
(7sport) - MLife
Re: MLD EVent Bivy on 03/04/2013 17:01:44 MST Print View

Just weighed my MLD Bivy.

It's 10.7 ounces.

Fully waterproof eVent top with a sleeve for a wire hoop.
Cuben fiber bottom
Side zip fore easy exit and entry
Full bug net window that zips separately from the eVent so you can leave it open with just bug netting for clearer nights.

Not as breathable or lightweight as some of the other fabrics, but there is anecdotal evidence that it performs better in certain weather conditions.

Max Dilthey
(mdilthey) - M

Full eVent bivy? on 03/04/2013 17:20:13 MST Print View

I would love to buy an MLD Full e-Vent bivy, but I don't see it on the site. What other recourse do I have for finding a full eVent bivy?

It looks like the way to go for me.

Nathan Watts
(7sport) - MLife
Re: Full eVent bivy? on 03/04/2013 17:27:48 MST Print View

Saw a Rab eVent bivy on the buy/sell forum today.

Jeffs Eleven
(WoodenWizard) - F

Locale: Greater Mt Tabor
Re: Re: Full eVent bivy? on 03/04/2013 17:37:11 MST Print View

Heres an interesting thread about bivys in alpine conditions

Max Dilthey
(mdilthey) - M

Gear Swap on 03/04/2013 17:38:34 MST Print View

I don't mind keeping my eyes open, but others are often faster. Maybe I'll keep putting up a WTB request.

Otherwise, anyone know how the cottage eVent bags compare with Outdoor Research's gore-tex bags? Looking at the 16oz Aurora bivy. I don't have actual knowledge as to how eVent compares to Gore-Tex.

I can also add a pound and get an OR Bivy with the huge wire frame. I mean, I'd rather have an MLD....

Nathan Watts
(7sport) - MLife
Re: Re: Re: Full eVent bivy? on 03/04/2013 17:42:05 MST Print View

"Heres an interesting thread about bivys in alpine conditions"

Haha, that's great Jeffs.
Max, the guy in that thread seems to have an abundance of knowledge about bivy bags. You should read it.

Max Dilthey
(mdilthey) - M

Haha! on 03/04/2013 17:52:16 MST Print View

Like I said, I do my research ;) My friend did Katahdin to Washington with a Gore-Tex one from OR. I asked him how the condensation went in the higher-altitude areas and the previous winter.

Just because I know about condensation doesn't change the OP of wanting to know which has the least. I don't know why Jeff is on a little campaign against me in this thread, but it's easy to separate helpful posts from useless ones ;)

If the intent here is to imply that I'm asking questions for no reason, I would wonder what my motivation would possibly be....

Edited by mdilthey on 03/04/2013 17:52:54 MST.

Hk Newman
(hknewman) - MLife

Locale: Western US
Re: Re: re: bivy questions on 03/04/2013 17:58:18 MST Print View

Waterproof/breathable bivy sacks were ultralight "bombproof" solutions back in the 1990s, when solo tents were 4 lbs. I used only bivy sacks for a few years (no tarp or anything) but they aren't exactly camping. Even with the GoreTex, never had much of a problem with breathability / moisture in three season plus, down to the low teens in Fahrenheit, but I was less fussy 10 yrs ago. Add: my experience was high Colorado summers and a New Mexico winter

Pros:Extremely snug when weather comes in and I slept very well.

Cons: It's an isolated feeling from the environment though since when zipped up the bivy wall is right in front of the face... all night long, even for one of the Outdoor Research with "gator mouth" frames on their Advanced Bivy. Getting in and out in the rain can be a pain, so I was thinking a small tarp before getting sick of my bivy and selling it several years ago..

They work great for mostly sleeping (after all, they are designed for climbers to use them exposed up high) and with cuben fiber, there's now only a little weight penalty to adding a tarp. May need one to get in and out in the rain. A smaller tarp is more efficient weight-wise but if you decided to sell a Trailstar, there's always gear swap. One neat thing about a bivy is cooking breakfast while still lying in while the rest of the party was huddled around the campfire. They had to break down their tents, I just rolled it all up. If you decide to go with just a tarp or tent later, the waterproof/breathable bivy makes a pretty neat winter shelter.

Ed: Add (see 1 para)

Edited by hknewman on 03/04/2013 18:52:52 MST.

Ian B.

Locale: PNW
MLD superlight on 03/04/2013 18:22:27 MST Print View

I can't find the thread at the moment but someone on BPL previously mentioned that they regretted purchasing the cuben over the silnylon MLD superlight as it wasn't holding up for them. Too bad the MLD eVent Soul Bivy is no mas. That was a bomber looking bivy for 16oz.

Max Dilthey
(mdilthey) - M

Re: MLD on 03/04/2013 18:27:45 MST Print View

I sent Ron an e-mail to see if he was still whipping them up.