Most Breathable Bivy?

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.

Max,

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.

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

http://40yearsofwalking.wordpress.com/2011/07/04/the-bivy-condensation-conundrum/

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.

Dave U.s thread

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=54121

Thanks Jeffs, that was the thread.

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.

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.

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

Heres an interesting thread about bivys in alpine conditions

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=73271&skip_to_post=624786

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….

"Heres an interesting thread about bivys in alpine conditions

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=73271&skip_to_post=624786"

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.

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….

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)

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.

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

Hey Ian.

I have a Soul with cuben floor. The floor has held up well for me. Prior to this I had the silnylon floor version, but never put it to use before jumping on the upgrade. The nice thing about the silnylon was that it packs up smaller than the cuben. They both weighed about the same (sub 12oz) but the silnylon floored one lacked the size zipper.

The cuben feels more robust in hand than the silnylon did, but maybe the cuben on the soul is heavier duty than that on the superlight.

I try to bring a 1/8" CCF ground sheet to protect it when I can – but that's not always the case if I'm trying to keep pack volume to a minimum.

"Waterproof/breathable bivy sacks were ultralight "bombproof" solutions back in the 1990s, when solo tents were 4 lbs."

An therein lies the problem. It's hard for me to justify buying a stand alone bivy system like the OR Advanced Bivy Sack or USGI bivy at 2.5 lbs when I can achieve the same result (with better comfort) with a Mid and ground cloth for half the weight.

The MLD superlight appeals to me as at 5.5oz it replaces a bug net and ground cloth and in some cases saving me weight but once I start shopping the REI, OR, BD, etc bivys which are pushing >16, 24, and even 40ozs the perceived benefit quickly disappears in my mind.

Only exception I can think of are camping in situations where a minimal footprint and quick deployment/recovery are in order.

keep an eye out for an integral desings unishelter in event. they made them for a couple of years and they show up on ebay and some of teh other outdoor boards evey once in a while. you might also try some of the retailers who may still have one in stock. integral desings makes a couple of diffrent event bivies currently, none of wich are full event. as far a weight goes, my id full event overbag is about as simple as it gets, and it's just over a pound. it will be tough to break the 1 pound barrier with a full event bivy that has any sorts of features.

That's good to know; I don't own any cuben products yet and I'm in the market for a few of these items. I'm sometimes torn between buy once cry once and othertimes just cutting a corner here or there so I can drop a couple Lbs quicker. I'm sure diligent site selection helps with either fabric as well and who knows what that bivy was subjected to.

I'll try to find the thread later but I've done so much web surfing for bivy reviews and there is so many threads to wade through it may become mission impossible.

If I can't get in touch with Ron about getting a Soul, I'll think about the superlight. I liked the Rab one on Gearswap but I think I value bugproofing too heavily. The price, weight, and materials are right, but it's wide open. I have been to mosquito hell and back.

It's a pain that so many good bivy's aren't available. I wonder if this points to a flood of new designs in late 2013, before winter…

I dont want to tell you what you want or dont want, but I think at 6'-2" you would be happier with the regular trailstar than the compact version.

Secondly, you shouldn't need a bivy for weather protection with the trailstar as it has great protection itself. I think that if you wanted something for any slight spray or wind you would be better suited with a breathable top with DWR such as Pertex, Momentem, etc.

You might have problems with condensation in the humid east coast with a bivy and that will be even worse with a less breathable top like eVent or Gore Tex. Of course YMMV.

Thanks Bradford. I'm on the same page as you on the Trailstar after talking about it previously in the thread. Also, I'm feeling you on that, but I got talked into eVent specifically. Do you think it's still significantly less than something like Pertex?

Does anyone know anything about the "Endurance" fabric MLD uses?

Endurance IS Pertex

Endurance and Shield as WPB membranes from the Pertex company

Quantum is by Pertex also, but its a water resistant nylon, not waterPROOF

MLD Superlight it is, then. Thanks, everyone! Much obliged!

Pretty sure MLD Endurance is not Pertex. I believe it's one of the iterations of M50, not a membrane fabric.

Ryan