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Most Breathable Bivy?
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Max Dilthey
(mdilthey) - M

Most Breathable Bivy? on 03/04/2013 10:31:58 MST Print View

So I'm loving the look of the new MLD Mini Trailstar, and I plan on ordering one. I also love camping in storms... I think I'm gonna pick one of these up for when my hammock is a liability.

If I wanted to get a bivy for sleeping underneath a tarp, what's the most breathable? I'd love one with foot venting options, and a LOT of space. I'm tall and I like to dry gear out next to me.

I need it to protect me from wind spray under the edges of a tarp, bugs, and saturated ground, although I will have a thin tyvek groundsheet.

Under 16oz is a plus, but not a prerequisite.

Price is no consideration.


Edited by mdilthey on 03/04/2013 10:33:18 MST.

Jeffs Eleven
(WoodenWizard) - F

Locale: Greater Mt Tabor
Re: Most Breathable Bivy? on 03/04/2013 11:03:08 MST Print View

Mld bug bivy

You kill me dude! :)
Google that stuff- search "bivy" on bpl

You aint dumb... All the answers are on the box that you are typing on. You just have do do a little work instead of asking the same ol q's that have been asked since the dawn of time

Ttdr vs smdld anyone?

Edited by WoodenWizard on 03/04/2013 11:08:38 MST.

Daniel Fish

Locale: PDX
... on 03/04/2013 11:03:16 MST Print View


Edited by on 06/12/2013 00:20:50 MDT.

Max Dilthey
(mdilthey) - M

I'm not fooling around! on 03/04/2013 11:49:09 MST Print View

It's not a stupid question. Check out the work they did in the Patagonia thread. Some forum users do quantitative tests on breathability. I want to know the difference, quantitatively, between Gore-Tex, e-Vent, and all the little proprietary spin-offs. Someone has a fabric that is slightly more breathable than the competition at a low weight. All bivy bags are "good enough," one is "better."

It's a serious question. if you can't answer it, don't worry about it!

Daniel, thank you for the heads up. I will cross it off my list.

Edited by mdilthey on 03/04/2013 11:50:58 MST.

Travis Leanna
(T.L.) - MLife

Locale: Wisconsin
Re: I'm not fooling around! on 03/04/2013 11:57:43 MST Print View

Check out Borah Gear. They have some bivys with M50 and M90 material.

John Harper
(johnnyh88) - MLife

Locale: The SouthWest
Re: Most Breathable Bivy? on 03/04/2013 12:11:53 MST Print View

A bug bivy with a full netting top would probably be the most breathable, but I don't think that's what you're looking for?

Look at Miles Gear:

The upper material he uses is very breathable and waterproof (see the "Uber Bivy" page for more fabric details). He can pretty much build you whatever you want.

Mole J
(MoleJ) - F

Locale: UK
Re: I'm not fooling around! on 03/04/2013 12:19:02 MST Print View

like he said. a search on this site will give you plenty of info. That's always the first port of call IMO.

But your question isn't totally clear anyhow.

You're talking about sleeping under a tarp with a bivi, but seem to be asking about WPB bivis judging by the 16oz figure (which is lower than any of the most breathable available in that class (i.e. something made of eVent)
Lighter than 16oz wpb's tend to be made of less breathable coated fabrics.

Water resistant topped bivi (with waterproof base) is likely more appropriate and more breathable than WPB. And much lighter. weight range 5-9oz.

Travis linked to one maker.

Ian B.

Locale: PNW
SOL on 03/04/2013 12:20:40 MST Print View

FWIW this is my next MYOG project once I finish my sleeping bag/quilt conversion.

I'm going to add a bug net and see how it works out.

Jeffs Eleven
(WoodenWizard) - F

Locale: Greater Mt Tabor
Re: SOL on 03/04/2013 12:35:29 MST Print View

I CAN tell you that none of the most breathable bivys will have a membrane.

Brett Ayer

Locale: Virginia
if you can't be helpful on 03/04/2013 12:42:47 MST Print View

Just my 2 cents,

You guys that post "run a search" are not being helpful. I don't know if you noticed but this forum is not over run with endless posts.

Since I have been a member here I have seen the post count drop off significantly, and one reason is the attitude some members have on here.

We are all hikers here and unless someone is an obvious troll, either be helpful or don't post.

OP, sorry. No help on the bivy but good question.

Edited by bfayer on 03/04/2013 12:46:35 MST.

Daniel Fish

Locale: PDX
... on 03/04/2013 12:49:14 MST Print View


Edited by on 06/12/2013 00:23:16 MDT.

Jeffs Eleven
(WoodenWizard) - F

Locale: Greater Mt Tabor
Re: OR Aurora Bivy or Uber Bivy on 03/04/2013 13:09:11 MST Print View

Suggesting that somebody who "isn't fooling around" do a little research before posting is snarky? Sorry.

And sorry for misspelling "Routa". Those are just the first three companies that popped into my elitist head.

Zpacks Quantum Bivy 5oz. $175

ooooohhhh Loooord.... Kum By Ya

Scroll down for Nisley's explanation of air movement

Edited by WoodenWizard on 03/04/2013 13:13:18 MST.

Mole J
(MoleJ) - F

Locale: UK
well on 03/04/2013 13:09:40 MST Print View

I thought my answer had useful content?

It appeared to me that the OP and subsequent post showed a lack of understanding about types of bivi/fabrics. I hope my post helped shed some light. Also my advice to do a little research was meant to be helpful.

That was my intent.

Not to reprimand anyone, as some seem to think necessary ;)

Stephen M
(stephenm) - MLife

Locale: Mind your own business
Re: well on 03/04/2013 13:45:51 MST Print View

Integral Designs all event overbag is the gold standard.

Edited by stephenm on 03/04/2013 13:46:26 MST.

Daniel Fish

Locale: PDX
... on 03/04/2013 13:57:33 MST Print View


Edited by on 06/12/2013 00:24:34 MDT.

Max Dilthey
(mdilthey) - M

Alright, looks like I need to be clear... on 03/04/2013 13:59:48 MST Print View

1. I did do research. I know what MLD and Integral Designs are making, and I know Zpacks makes split bivy's with a water resistant top and a bathtub bottom. I also know there's a sea of bivy's from non-cottage companies and all use independently developed fabrics touted as "breathable." I have no idea which stand out.

2. I read the entire most recent thread on bivy breathability, but it's much older. Every company seems to be launching redesigns this spring, I have seen new tents from three companies alone, and new sleeping bags from one as well.

3. Unhelpful is assuming since you yourself found out over the course of a few months or years, I must have too, and otherwise, I have failed to do enough on my own. Agree with everyone calling a few users out for being snarky- save it. At the risk of sounding cocky, the amount I contribute to other people when I have good info earns me the right to shortcut straight to the experts once in a while.

Now, in case I'm being unclear...

What I'm looking for is to know

1. Which fabrics are Water-Resistant/Breathable and which are Waterproof/Breathable. I know Pertex is the former and Goretex is the latter, any other examples worth knowing about? I'm fairly certain I want the former, since I'm using a tarp. I want the bathtub waterproof bottom (hopefully tough stuff) and a nice, light, water resistant top for wind spray and bugs. And good netted venting so I don't condense all over myself.

2. What are the low-weight options that fit what I'm looking for, in either the WRB or WPB category?

3. Anything I'm wrong about philosophy-wise when it comes to a bivy. I have never used one. Maybe I need more than I think for sleeping in storms. Remember, this is a New England storm camping kit, up to 50MPH gusts (The trailstar goes to 60mph).

Edited by mdilthey on 03/04/2013 14:01:24 MST.

Nico .
(NickB) - MLife

Locale: Los Padres National Forest
Most Breathable Bivy on 03/04/2013 14:05:16 MST Print View

I'll echo a couple of the other commenters...

If you're considering a shelter like the Trailstar (or Trailstar mini), these provide a good bit of coverage so you don't need to rely so heavily on a bivy for weather protection. Instead it's main purpose with a shelter like this is to offer some wind/bug protection, perhaps a little splash protection and can serve as your groundsheet (no need for the tyvek then).

Because these bivy's aren't doing full weather protection duty, folks opt to go for a lighter water repellent but breathable (DWR) bivy over a fully waterproof (WPB) bivy. The DWR style bivys tend to weigh significantly less (5-6oz is pretty standard) than WPB bivy (probably most start around 16oz and go up from there).

You still get a waterproof floor (usually silnylon or cuben) with the various DWR bivys but the top half of the bivy is constructed out of various materials that tend to breathe better than the waterproof fabrics but that actually still also do a pretty good job at repelling light spray, spindrift, etc.

Lot of top materials to choose from in this regard... pertex, M50, M90, etc. I'm not sure on how they rate compared to one another, my hunch is that in the real world they're all fairly comparable. Of course the most breathable of all is a bug bivy (solid silnylon or cuben floor/sides with bug net top).

If you truly want a fully WPB bivy, I'd agree with Stephen that an eVent bivy is the way to go.

If you want to look at DWR bivys, most of the cottage companies offer their own version. I have a bivy from Katabatic Gear. My GF has one from Borah gear. Both serve their purpose well.

A couple of final notes... you mention being tall:
- Most of the cottage gear makers offer their bivys in various length and width options, so you can get it scaled to your liking.
- I've read somewhere (perhaps the Trailstar mini thread) that the trailstar mini might not be big enough for taller folks. Maybe check with Ron at MLD before you commit to this shelter... or go for the "normal" Trailstar. I use one and love it; although I have yet to use, or need, a bivy with it.

Edited by NickB on 03/04/2013 14:19:58 MST.

Herbert Sitz

Locale: Pacific NW
nettent rather than bivy on 03/04/2013 14:07:28 MST Print View

". . . loving the look of the new MLD Mini Trailstar, and I plan on ordering one. . . .
If I wanted to get a bivy for sleeping underneath a tarp, what's the most breathable?"

The miniTS is of course smaller than regular TS and Ron Bell has said it may not work well for people taller than 5'10". Why not get the full Trailstar for 2.5oz more and then not worry about having to bivy at all? Coverage is good with Trailstar, you're not going to get splatter if you set it up right, just get an inner net and you're good to go. You'll have (1) no worries about breathability, (2) more space, and (3) much less than 16oz weight. See BearPaw Pyranet, Ookworks trailstar designs, MLD's bug bivy, and I assume inner nets like MLD's and SMD's Serenity net tent can be made to work without much problem.

I don't think you'd need bivy bag merely for splatter coverage with mini-TS, either, but maybe it's hard to tell at this point.

Max Dilthey
(mdilthey) - M

Stephen on 03/04/2013 14:08:43 MST Print View

Stephen, it looks awesome but there's no bug net from what I can tell. That's a must for me; I hate sleeping with critters and I don't find headnet sufficient at night.

Any similar ones?

James Klein

Locale: Southeast
Re: Alright, looks like I need to be clear... on 03/04/2013 14:11:06 MST Print View

Pertex makes wpb stuff -- pertex shield I believe.