clayton c

Bivies aren't a good thing if you're claustrophobic. I woke up one morning with my head, right shoulder and arm sticking out the face hole of my bivy ! ? I've have since, removed the zipper and installed Velcro around the entry opening so I can get out in a hurry if I have to.

staehpj1

EDIT: Corrected bivy weight.

OK, so here is my latest thoughts on what I am doing for the upcoming ST tour...

I went with the REI Minimalist Bivy. I decided that I would try combining it with a mini tarp. I considered making one possibly as small as 3' x 3', but wound up going with a larger Mountain Laurel Designs "Dog Tarp".

The numbers look like this:

• Tent (Eureka Spitfire 1 with 6 Needle stakes and no footprint) - 2 lb 9 oz.
• Bivy Only (REI Minimalist) - 15 oz.
• Bivy and Mini-tarp (5' x 5' MLD Dog Tarp 5.9 oz with 3 MSR Needle Stakes 1.1 oz) - 1 lb 6 oz.

It looks to me as if the tarp/bivy combination will actually make it easier to set up camp and cook in the rain. It will also allow opening vents on the bivy or even leaving the upper portion of it open if bugs are not too bad. If I choose to it also has enough room that all my gear can easily fit under the tarp. In the past my habit has been to leave the gear on the bike and in the panniers, but since going away from panniers that may change.

On trips or portions of trips where the weather is expected to be good and/or available shelter from the rain likely, the tarp can stay home or maybe be mailed home. I am thinking of situations where there is usually an option to be under a picnic pavilion or some other roof.

If it is really hot and "buggy" the tent may be preferred. I am thinking only for when the bivy and silk liner are just too hot and bug protection is needed.

Worst case I can call it a failed experiment and have my wife mail me my tent.

von petrol

I to have been thinking of getting a bivy. This one looks interesting:

https://www.milesgear.com/UberBivy.html

BigAura

Just for comment, the REI site claims 15 ounces for the bivy. Are you using your actual measured weight?

fuzz2050

I admit, I'm a little confused as to the point of a bivy that heavy. If it's over the one pound mark, you're just a few ounces away from a tent (The Tarptent Contrail is only 24 ounces), and more than the weight of a much larger tarp (The generic silnylon tarp from campmor is just 13 oz in 8X10). A heavy bivy just seems like the worst of all worlds.

staehpj1

OOPS. I meant to list it by the claimed weight and just got it wrong. I will get an actual weight when I remember to check it.

Bekologist

my experience with tarps is that a 5x5 tarp is not big enough once the weather rolls in.

I've settled on a 8x10 foot Integral Designs sil-tarp 2 as the ideal size for wet weather camping. its fourteen ounces, but well worth it in weather protection.

It's actually quite pleasant, MUCH more roomy than a tent, way better ventilation, and you can cook under it if you want.

I would not be cooking in a Shires Tarptent or any other one man ultralite tent for that matter.

but 5x5 is a skosh too small once the weather makes you actually need a shelter.

prathmann

The regular length version is listed as 15 oz. and the long version is listed as 1 lb. 1 oz.

staehpj1

Just checked and the regular actually is 15 ounces (measured). The stuff sack is 0.7 ounces additional if used.

staehpj1

A few reasons why I didn't go the tarp tent:

• The tarp tent is substantially more expensive.
• I can try the REI bivy and if I don't like it they will take it back for any reason including that I just decided I don't like it.
• The tarp tent is not as warm. In my case that may mean the difference between taking my 17 ounce sleeping bag and my 2 lb 12 oz sleeping bag.
• The bivy will stand up to wind, and blowing snow or rain that I would be concerned about with the Tarptent.
• I can easily use the bivy under a picnic pavilion roof, in an entry way, on a host's porch, under a shed or corncrib roof, even under a vehicle, or pretty much anywhere.

The tarptents have their advantages as well, but for me right now they didn't make the cut.

Standalone 

A mesh hooped bivy+ a pyramid tarp tent (golite 4) = protection from all elements for both you AND a bicycle/gear, and a place to cook and live. Worth the 5 or 6 total lbs. For nice weather that hooped mesh bivy can work alone, or with a cheap nylon or silnylon tarp. Modular is what works for me. I haven't put a huge amou nt of $$ into it as I've kept on the lookout for closeouts. Check out campmor.com's "hot deals" section.

revelo

A waterproof/breathable bivy is a good idea for deserts, where there is the possibility of strong winds. The alternative is a freestanding tent with very strong poles to cope with the wind. I wouldn't travel where wind is common, but I will travel where wind is occasional but can be ferocious when it happens, like the southwest deserts of the United States. Stakes will not hold in desert sand and lightweight freestanding tents will break.

A bivy can also be useful in certain winter applications (snow caves), though I don't have much experience here. And of course it is useful as an emergency shelter.

Anywhere you can get stakes to hold and are sheltered from strong winds by trees, a tarp plus bugbivy is the better choice. Here is my homemade tarp + bugbivy (735g or 26oz including stakes and rear pole):

There are lots of commercial versions like mine. Tarp-tents are another possibility for about the same weight.

Condensation in a bivy will be horrendous under all but optimal conditions. Never use a down bag in a bivy. Here is my homemade bivy setup for typical desert conditions (no rain):

wiiiim

I'm curious though, what is this 2 lb 9 oz tent you already own? If it's some light weight free standing model like the MSR carbon reflex or hubba or Big Agnes copper spur you can put it up without inner tent, just like a tarp, which would reduce the weight well below 1kg
This is an interesting option on tents nowadays, when bike touring I don't mind the extra 500g in return for more comfort, but for a trek in between a tour where weight is a much bigger factor i would probably just do with the basic shelter

staehpj1

In this case it is a Eureka Spitfire. I really don't see the advantage in this case. The reasons:

• Since the inner tent is essentially not much more than a bug bivy already, It is something like 8 ounces. To pitch the tent sans inner tent, I'd probably have to add the 4 ounce footprint (which I do not normally use). So it winds up saving a pretty insignificant amount of weight. and offer no bug protection.
• The resulting setup would be not nearly as warm as a bivy and probably would mean I'll need my much heavier sleeping bag. If you factor in the heavier bag the rig is actually over a pound heavier.
• Since the first half of this trip is in the American Southwest my hope is that I will be sleeping under the stars much of the time and using the tiny mini tarp for any hopefully infrequent rain.

This is a bit of an experiment on my part, so we will have to wait and see how it goes. If the bivy/tarp is a flop, I'll just have my tent mailed from home.

staehpj1

I have heard widely varying opinions on that. I guess I will find out.

revelo

Condensation is poorly understood by most campers. The problem is one of physics and there is basically nothing you can do if the physics works against you. At least with synthetics, moisture doesn't cause a total failure like it does with down, which is why down should be avoided where condensation is a potential problem.

Down in waterfowl is different from down in sleeping bags. In waterfowl, the down is anchored to a muscle. So even if it gets wet (it shouldn't in living state, because it would then be protected by grease), the down can't move and so will eventually dry off from body heat. This is exactly how synthetics work. That is, when they get wet, they can't shift position, so body heat will dry them out. But down in sleeping bags is not attached to anything, so when it gets wet, it falls to the side and then the body heat is lost rather than being used to dry the down out.

Cold and raining is typically the worst condition for condensation, and this is precisely when you can't afford problems with your insulation. But not all cold and raining is the same. It depends on the humidity level, how much moisture your body is producing (if you are acclimated to cold, your pores will be more constricted than if you are acclimated to heat), how thick your sleeping gear is. Even the best ventilated bivy will have severe condensation under worst case conditions. And well ventilated bivies are heavy. Normal bivies will typically have severe condensation whenever it is cold and raining.

Bitterly cold and snowing is actually not that bad, assuming your sleep gear isn't too thick. What happens is that you'll feel chilly, because your sleep gear is not up to the bitter cold. But for the same reason (namely, sleep gear not that thick), the dewpoint is pushed outside the bivy, so you don't get condensation.

You can always get a bivy to work with down by using a vapor barrier liner, but that is a royal PITA, IMO.

Niles H.

This was an excellent thread on the subject of bivies, and I am resurrecting it here to in case anyone has additional experiments or experiences or insights -- or any other thoughts on the subject.

What are your own experiences with bivies, or evaluations of them? What do you like and not like about them?

If you could design a bivy from scratch, what features or improvements would you want it to have?

Or, have you found other systems that you prefer after comparing them with bivies?

staehpj1

I can report that it worked out very well for my Southern Tier and my abbreviated Colorado Rockies Tour. I have since bought a bug bivy from TiGoat and a side zip from Borah. Additionally I now have an Integral designs Siltarp 1. I plan to mix and match all of that depending on the trip.

Slussman

There are tons of military surplus bivy bags on eBay. I might just pick one up for stealth camping since they're all camouflage and gore-tex at that.

Sachelis

Like much of the gear we use, it’s personal preference. I love the bivvy for fast alpine mountaineering trips, but not for bike tours. The bivvy doesn’t let me bring in my panniers, get dressed, sit up and read a book, change a flat tire, make sandwiches, etc. Hammocks are light but can be cold with air circulating below; and tarps don’t keep out the bugs.

My Big Angus Copper Spur UL2 tent weighs 3.7 lbs (with a footprint, huge fly, stakes, and poles) versus my Black Diamond bivvy at 2.1 lbs (it has one pole for headroom). The difference, 1.5 lbs, is the best 1.5 pounds I carry.

(Click the pics for larger views.)

hueyhoolihan

a few long term tours/backpacking trips confirm my preference for a very, very light tent over a bivy. the extra weight is worth it for me too. of course, if i had to pull my sleeping quarters up vertical cliffs, i might reconsider.

but it was always so sweet to drop my down bag in the bivy and then stuff the whole thing inside the bag's stuff sack. completely waterproof. nice.

andrewclaus

I've tried two different light, non-breathable ventilated bivvies on two short hiking trips and did not like either, for the reasons already outlined. As stated so well above, I'd feel differently if I were using my shelter on the way up a cliff. I do appreciate the OP's concern about insulation weight and that's a factor I'd never considered, but in my experience the condensation problem looms larger.

My favorite solution for three season touring so far, overall, has been the $200 Tarptent Contrail at 24 oz with a $200 down quilt at 20 oz.

staehpj1

A bit more about how the bivy worked out on the Southern Tier and in the Colorado Rockies...

I really like that I could just put my sleeping bag on top of the bivy and cowboy camp. If it started to rain or got cold and windy I could just climb in. That was really nice. Sometimes I pitched the mini tarp and sometimes not. If I didn't pitch it and rain started I would just pull the tarp over me to cover the mesh window.

I fairly often had had a bit of condensation down near my feet. It was usually in the form of a few drops of water or a bit of ice either on the inside of the bivy or the outside of the DWR sleeping bag. In all cases it was easy to just brush it off or wipe it off.

The conditions where it did not work well was if it was hot and buggy. In those conditions it was pretty unpleasant. It was really bad only one night in Louisianan on the ST and even then I managed to get a decent night's sleep. In the future, if I go when it is supposed to be hot and buggy I will take a mesh bivy.

My current choices are the REI bivy (15 oz), a Borah side zip (7 oz.), and a TiGoat Ptarmigan mesh bivy (5.3 oz.). I still have the MLD Dog Tarp (4.9 oz.) and a Integral Designs Siltarp 1 (7 oz.). So I have a pretty good range of lightweight choices depending on conditions expected. I think my go to setup will be the Borah and Integral designs tarp or the bug bivy and ID tarp if hot and buggy conditions are likely. Taking both would still be pretty light if that seemed necessary.

Niles H.

Fascinating thread.

Thanks for the updates.

I've been hearing about bivies with armholes, but no one has mentioned makes and models. If anyone knows more, please post.

The Big Agnes sleeping bags that have armholes and foot drawstrings, and can be 'worn' around camp, could be matched with similar bivy designs.

I'm even thinking of modifying an existing bivy in this way.

arctos

Niles:
Look for the Hilleberg Bivanorak which has a drawstring bottom to pull up to waist level to also use as a cagoule or rainjacket when not used a a WPB bivy.