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MilesGear Uber Bivy
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David Miles
(davidmiles) - F

Locale: Eastern Sierra
MilesGear Uber Bivy on 03/05/2011 00:44:27 MST Print View

Thanks to Roger for finally getting me to the right forum to post this.
I started making the Uber Bivy last September. This was after almost a year of prototypes.
After an especially bad night on a Mt. Whitney rescue in a small GoreTex bivy I decided to make something better.

Dave Miles

Ken T.
(kthompson) - MLife

Locale: All up in there
Re: MilesGear Uber Bivy on 03/05/2011 10:29:38 MST Print View

What am I going to do with 2 65" single piece poles in my pack? Seems kinda heavy too. Too heavy of material used on the top. Why a Tyvek bottom? You could get a TT Moment for just a few more ounces and sit up, and have a real vestibule.

todd h
(funnymoney) - MLife

Locale: SE
Re: MilesGear Uber Bivy on 03/05/2011 16:28:52 MST Print View


These look great! Is this the same material Driducks are made of? If so, I use a hammock underquilt cover made from it, as well as a simple sleeping bag cover (both old models made by JRB). I love them both and baby them so they'll be around as long as possible.

The top cover (basically made like a quilt w/sewn-in footbox) works great by itself as a quilt in warm temps, as would your bivies.

Some on this site may hesitate due to the weight, but the breathability and waterproofness will work great!


David Miles
(davidmiles) - F

Locale: Eastern Sierra
Re: Re: MilesGear Uber Bivy on 03/05/2011 21:43:24 MST Print View


I have designed some lightweight tarps/tents. The advantage of this bivy is for protection against high winds and spindrift snow. The poles just get bent into a horseshoe shape and put inside the pack. Having a seamless pole makes setup and take down very fast and easy. Plus, many places where I go above tree line make it difficult to use stakes and guylines.

Do you know of something better than Tyvek for the bottom?


This is not exactly the same as Driducks but similar. Yes I chose this fabric because of it's breathability and it's fully waterproof. I didn't want something that was only water resistant or a DWR. Certainly not as durable as a 3-ply GoreTex, but if you treat it well it should last.

Ken T.
(kthompson) - MLife

Locale: All up in there
Re: MilesGear Uber Bivy on 03/05/2011 21:52:15 MST Print View

"The poles just get bent into a horseshoe shape and put inside the pack."

Photo please

Something waterproof for the bottom. Something strong enough that you don't feel the need for a separate ground sheet. Cuben?

Just trying to figure out where all the weight comes from. My 8' bivy weighs in at 10.5 ounces. Not as wide as yours. But i don't see that I/most would ever double up in there on purpose.

With no stake loops, I sure hope it does not blow away while you are up taking a pee.

Edited by kthompson on 03/05/2011 21:52:55 MST.

David Sirull
(aysrav) - F
Like it a Lot on 03/07/2011 19:55:47 MST Print View

<"The poles just get bent into a horseshoe shape and put inside the pack.">

Not an aspect of much concern to most perhaps, but I happen to really like the way it looks. It doesn't pretend to be a tent or tarp or anything but a bivy. That means sleeping outside in your sleeping bag, but protected from the elements. I'm on the short side, however. Kinda wish there was a 6 ft version.
Curious about the poles though. If the pack size is 5 X 15, how are you able to fit them in the stuff sack? Or does that mean the poles don't go in the stuff sack, but rather in one's backpack?
I'm sure there would be nights when I'd eat these words but I also like the concept of no stakes or guylines. Just sayin'.

David Miles
(davidmiles) - F

Locale: Eastern Sierra
Re:Like it a lot on 03/08/2011 01:45:26 MST Print View


Yes, the poles don't go in the stuff sack. It seams a little awkward when you are just holding the bivy and poles separate.
However, it is very easy to fit the poles in my pack. I am actually designing a pack that uses the poles as the frame.
This would give a pack + bivy < 3.0 lbs. Making the bivy a foot shorter only cuts off 1 oz. It doesn't seam like it's worth having different patterns. I guess I could cut one a foot short if you really want it. I won't make it any narrower since I have spent a lot of effort getting the arcs just right. Just finished #25 tonight!

There are definitely lighter bivy sacks out there, but I didn't want to sacrifice the great breathability or total waterproofness.
Part of the weight differential comes from the 2 oz/ sq yard fabric. The other comes from it being wide. Internal circumference at the top pole is 102 inches! My requirement was actually that I could double up in it. The night on Mt. Whitney that caused me to make this bivy (just for me at first) was 5 deg F and 50 mph winds with spindrift snow. I wanted to be able to get dressed inside, protected from the elements, and then emerge ready to face them.

As long as I have some gear inside the bivy it doesn't blow away during a pee break. If we leave our bivys for the day while doing a summit we just fold them in half and place a few rocks on top.

Thanks to both of you for you comments. I always like to hear others thoughts. I think I have a great bivy but I'm sure there are still ways to make it better.


kevin smith
bivy on 03/08/2011 07:30:54 MST Print View

everyone has given some good advice here in my opinion

those bivy s are pretty cool one suggestion though and this is just my own thoughts on it a lot of people here are looking for a bivy that can fit a 2,5 inch blow up pad and a bag inside such as the raven or meteor bivy s i don t know how you would keep the weight down but if you could come up with something very light and waterproof such as ken t s suggestion of cuban you would probably get a lot of interrest in something like that i know they would have to be a little more expensive than the standard material bivy s but i bet you would be able to move them if people knew their neo air or ba aircore pad would fit in it along with thier sleeping bag
again just my humble opinion looks like you have a good start though

good luck with your venture


David Miles
(davidmiles) - F

Locale: Eastern Sierra
Uber Bivy on 03/08/2011 09:03:12 MST Print View


Thanks for the comments. Especially in nasty weather, I wanted room for my XL NeoAir. I also wanted a bottom that was tough enough to protect my rather fragile NeoAir from puncture. It has a slow leak that I have to find soon. It's not my winter pad, so I have a little time. I have not used Cuben yet so I not sure of its durability compared to the Tyvek housewrap. I have used Si Nylon on some projects and feel like it's just to lightweight for a floor. I have slept all night with this bivy in a puddle of water and had no water come through the floor. I like lightweight gear, but good performance it the biggest driver for me. The idea of pitching a tarp in the storms I find myself in just sounds dangerous. In rescue, I don't get to pick good weather or nice campsites. The people who are lost or hurt chose them for me. This suits me since I really like the challenge of foul weather. I love getting in my bombproof cocoon to sleep.

As for a more simple bag. My Basic Bivy uses the same waterproof/breathable material on top and bottom. This is a good choice for winter where bugs are not an issue. Again, this one has lots of room inside, but no poles, zippers, or netting. I used this one 2 weeks ago to protect a lost skier from the helicopter downwash during a rescue.

The smallest one I make is just a sleeping bag cover or emergency bivy. I have spent a handful of nights in my Thermolite bivy by AMK. Its works as advertised, but I wanted a more breathable version.


David Miles
(davidmiles) - F

Locale: Eastern Sierra
Uber Bivy Winter Trip on 06/09/2011 09:26:31 MDT Print View

Thought you might like to know about a recent trip involving one of my Uber Bivy sacks.

One of my customers (Ryan) took his bivy on a winter ski trip to try it out.
The other 2 with him were going to sleep in the snow cave.
One of the 2 in the snow cave bailed out and slept with Ryan in the Uber Bivy.
Now this bivy is really designed for one, but they stuffed 2 in it for the night.
That is not as remarkable as the fact that with 2 of them it still had no condensation at sub-freezing temps.

Now for the part that is truly amazing............ The bivy was covered by almost 2 feet of snow!

Andy F
(AndyF) - M

Locale: Midwest/Midatlantic
MilesGear Bivies on 09/10/2011 13:00:15 MDT Print View


Have you used either the Uber or Basic bivy in the rain? Do you typically use one of these bivies in warmer/rainy weather, or only in snow?

How does the durability of the material compare with both DriDucks and Tyvek?

Mark Mathis
(78Staff) - F

Locale: NE Florida
big guy thoughs on 09/10/2011 20:24:53 MDT Print View

As a larger guy, I'm always looking out for "better fit" options, so I like the idea that it is slightly longer, slightly wider, and fits a 25" neoair. Also, I've come to learn that anything is XL size is going to weight more than your typical quoted "medium/standard" size weights we see online/books/mags/etc. That being said, I'll echo the other posters that it "seems" heavy for what is. Although, I guess it leans almost more towards a small single person tent-bivy than your typical bivy sack. How much of the weight is in the poles - it looks like one could forego the forward pole possibly?

The Tyvek bottom throws me too - I had always though Tyvek could wet out under constant pressure. I could be wrong on that, but since in the same price range as the Raven, SL, etc I would be leaning towards a marketable brand name fabric option vs homewrap. Also, there are no stake loops at all, or is it just being marketed as not requiring stake out?

David Miles
(davidmiles) - F

Locale: Eastern Sierra
Re: MilesGear Bivies on 09/11/2011 00:11:11 MDT Print View


My son and I have had a lot of fun testing different designs during a good soaking of the lawn sprinklers. We used headlamps at night and paper towels to see if we could find a leak. Both fabrics passed with flying colors. I just can't stand the idea of have a bivy that is only water resistant. That just means that it's only a matter of time until you're wet. I spent 2 hours in a local park with the really heavy sprinklers hitting my bivy and still did not get any leaks. I found out in the morning that with my groundcloth being larger that the bivy, I had also slept in a puddle of water between the bivy and groundcloth. So what! I could do that with a sheet of plastic. The amazing fact for me is that during these tests I don't get all hot and sweaty. It somehow manages to breath enough while being rained on. The top material has better durability than DriDucks but not a good as Tyvek HomeWrap.


I was shooting for the the small footprint of a bivy and room to get things done (like dressing) while inside. I like to have my gear with me out of the weather. I know it's not the lightest on the market, but that not what I needed. As for the poles, I would give up the top pole first. Th forward pole turns out to be one of the greatest features of this design. First it keeps the zipper flap covering the zipper. Second, it keeps the doors shape. This allows me to open and shut the door very quickly and thus reducing the time the gear inside is exposed to the weather.

My experience so far with HomeWrap is that it is very waterproof but not breathable. There are some soft Tyveks that are more breathable, but not as much as my top fabric. I know the Tryvek has a somewhat "ghetto" look, but I'm care more about function. The same goes for the top. I would like to have had a bright color other that white, but it would cut back the breathability. I might try cuben, but it is so expensive! The stake loops would add stress points that could tear the fabric in high winds.