Adding bivy to sleep system

Gerard Marcaurele

Well Known Rokslider
Joined
Aug 9, 2017
Messages
462
Location
Southeast Texas
I’m running a couple different sleep systems:

1) Ozark Trail dome tent for truck camping 2) mountainsmith mountain shelter LT

I run the same Slumberjack 0° bag with both, but in the dome tent I use a cot.

I am thinking of buying a RAB alpine bivy to add for warmth for both systems. I’ll be sleeping in AZ in Jan, which seems to have the ability to be in the teens. I’m a cold sleeper, but I am curious if adding the bivy would give me the extra insulation needed to take that 0° to a -20° type rating. It’d also give me some flexibility setting up my mountain shelter and making that a more versatile system.
Does anyone have experience with the RAB and know how much warmer it’ll make my setup?
 

KyleR1985

Well Known Rokslider
Joined
Jul 28, 2019
Messages
366
I use an EE recon bivy with floorless shelters. It's a 4-6" or so bathtub floor, net top, with some additional material at head and foot. It adds about 10* that I can sleep comfortably with a quilt.

I looked at the Bivy you're considering. It's a body bag essentially. There seems to be quite a few lighter, less restrictive, and less moisture retaining ways to gain an extra 10-20* of capability.
 

tdot

Well Known Rokslider
Joined
Aug 18, 2014
Messages
1,887
Location
BC
I've only briefly played with the Rab, and decided it wasn't right for my needs. But it won't take you from a 0 degree system to a -20. It would only add 5-10 degrees to your entire system, especially if you are a cold sleeper. I find they help more with quilts, then sleeping bags. You'll need to add insulation, an over quilt is an option.
 

Desk Jockey

Well Known Rokslider
Joined
Apr 5, 2015
Messages
5,154
Longtime bivy fan. I went from a 2# GI goretex to a few OR versions. Bought a bora bivy a couple of years ago and none of my others have been used since. Part of the appeal is that I am 6’3” and have 50“ shoulders. They custom cut to my specs.

I would say in addition to wind and moisture, it adds some comfort to my bag. I was in a 30* rated quilt when it got to mid 20s and was fine. I also tend to like being able to keep my bag and pad inside the bivy when I breakdown camp. Just wrap it up and stuff it in a sack.
 

zacattack

Well Known Rokslider
Joined
Aug 23, 2018
Messages
1,270
Location
Michigan
I’m running a couple different sleep systems:

1) Ozark Trail dome tent for truck camping 2) mountainsmith mountain shelter LT

I run the same Slumberjack 0° bag with both, but in the dome tent I use a cot.

I am thinking of buying a RAB alpine bivy to add for warmth for both systems. I’ll be sleeping in AZ in Jan, which seems to have the ability to be in the teens. I’m a cold sleeper, but I am curious if adding the bivy would give me the extra insulation needed to take that 0° to a -20° type rating. It’d also give me some flexibility setting up my mountain shelter and making that a more versatile system.
Does anyone have experience with the RAB and know how much warmer it’ll make my setup?
You should check out Borah Bivy
 

mlgc20

Well Known Rokslider
Joined
Oct 29, 2018
Messages
1,180
Location
DFW, TX
What sleeping pad are you using? Might be worth getting a higher R valued sleeping pad.
 
OP
Gerard Marcaurele

Gerard Marcaurele

Well Known Rokslider
Joined
Aug 9, 2017
Messages
462
Location
Southeast Texas
What sleeping pad are you using? Might be worth getting a higher R valued sleeping pad.
I’m using a klymit insulated static V at the moment not sure what the R value is on it. I’ve been comfortable into the mid 30s with it, but below 30° I get cold. Below 20° and I just don’t sleep.
 

mlgc20

Well Known Rokslider
Joined
Oct 29, 2018
Messages
1,180
Location
DFW, TX
I’m using a klymit insulated static V at the moment not sure what the R value is on it. I’ve been comfortable into the mid 30s with it, but below 30° I get cold. Below 20° and I just don’t sleep.
That pad has a reasonable R value. My experience with bivys is that they add very minimally from a warmth perspective. They are useful for keeping off weather off you if cowboy camping. But, if you're already in a tent/shelter, I don't think it will give you much. Maybe 5 degrees.
 
OP
Gerard Marcaurele

Gerard Marcaurele

Well Known Rokslider
Joined
Aug 9, 2017
Messages
462
Location
Southeast Texas
That pad has a reasonable R value. My experience with bivys is that they add very minimally from a warmth perspective. They are useful for keeping off weather off you if cowboy camping. But, if you're already in a tent/shelter, I don't think it will give you much. Maybe 5 degrees.
Thanks! I think I’m going to have to look into a bag liner of some kind
 

WyoBC_99

Member
Joined
Dec 10, 2018
Messages
52
Location
Colorado
Seconding the comment above about pad insulation - In my experience, adding a bivy under an existing shelter is going to add minimal warmth (or risk condensation with the heavier bivies) but a closed cell foam pad used in combination with an air pad makes an instant difference.
 
Top