Down Bag and Bivvy

The SOL bivy is not breathable. Use it as close to your skin as possible because any fabric under it will get moist. Trash bags work too.

If you are going using in temps above freezing then I do something like a 40 degree bag/quilt inside a light Bivy that is water resistent and fairly breathable. Something like the MLD Superlight Bivy or the Katabatic Gear Bristlecone Bivy come in around 7oz. Just make sure you stick with a good brand of Bag that is true to it's rating. WM is a great brand. The bivy will provide extra warmth and protect your down.

If you're asking whether a 30-35F bag will be warm enough, it would help to understand what time of year you'll be using it; whether you use it under a tarp or inside a tent; and what type of pad you'll use underneath.

For shoulder seasons under a tarp on a NeoAir or Synmat UL 7 for example, you may be better served looking at a 20-25F bag. Inside a tent, on a NeoAir All Season or a Downmat, or during summer, the Highlite will be much more comfortable.

hey mate,
I live in the PNW as well and would recommend a 20 deg quilt if you are looking for something that is super versatile through 3 seasons and wont melt you in the summertime. The price/weight penalty for a 20 deg vs a 30deg is minimal and the versatility gain is huge (especially with the huge venting potential for a quilt in summertime)

The best deal around IMO as far as quilts/bags go are the gear that Tim is making at Enlightened Equipment. Hes got a line called the Revelation X that uses seconds fabric that is by far and away the best deal you can get on a superlight well-made quilt or bag. Heres a link (I just bought one for my wife yesterday – I use a Golite Ultra 20 with 3.5oz overfill but they are unavailable and cost more than a Revelation X now) –

http://enlightenedequipment.com/revelationx.html

Email Tim with your dimensions, but I would recommend the 20 deg 6'6 Wide style w/o 30% extra overfill for the perfect all around PNW 3 season quilt (195US before shipping with 4 week wait time).

cheers,
Brendan

Sorry, forgot to add, I will be hiking in the Early April to Early October time frame. I guess I can scratch the SOL Bivvy then. I will look into the MLD ones. I use a trimmed down RidgeRest for my pad and sleep under a Kifaru ParaTarp. After my bag, my next purchase will be a bivvy and something to keep the bugs off if the bivy cant do that.

my most recent list is here.

http://www.geargrams.com/list?id=7733

I agree with previous poster about a 20 degree rating, especially for early April. If you get into elevation at all, you've got a good chance of dipping below 30 in April. Enlightened equipment quilts are awesome. If you prefer a bag, check these (locally made) bags for an affordable, light, cozy 20 degree bags:
http://www.featheredfriends.com/Picasso/Bags/Product/20Degree.html

on the material the bivy is made of and how breathable it is

for example

i use a 20 deg western mountaineering hi loft down bag (alpinlite) with a bivy that is silnylon on the bottom and momentum 90 on top

my hiking partner uses a bivy that is silnylon on the bottom and momentum 50 on the top with a marmot atom 40 deg down bag

a few weeks back we were camped at low elevation under a tarp in damp conditions

temps dropped to 24 deg that night and we were both sleeping in our bivy s under the tarp and woke to frozen conditions

i woke to very little condensation inside my bivy and my partner woke to a soaked
outer shell on his bag in the m50 bivy

so it just depends on the breathability of the material the bivy is made of and the conditions you will be using it in

john west builds a nice bivy with custom options for a good price so you might hit him up and pm him for a price he can build the bivy for your needs and add in any zipper option you wish and his finished product is usually under 8 oz

kevin

you can definitely cross the SOL off your list as a bivy w/ a bag (nice piece of kit to throw in a small day pack however)

I agree that April/Oct is getting into shoulder season and a 20 degree bag/quilt gives you a lot more flexibility

I should add that a bivy in addition to shedding light moisture and wind (and bugs! :)), also boosts the rating of the bag/quilt

So, the M90 is way more breathable than the M50?

I would expect them to be about the same, or maybe the M50 to be a little more breathable

Maybe there's some other variable here

You had a warmer bag, but I would think maybe that would make condensation worse

Any bivy over your sleeping bag absolutely must be breathable. Otherwise condensation of the moisture coming from your body will soak your sleeping bag's insulation. Even WPB fabrics like Goretex used as a sleeping bag shell or a bivy will cause condensation inside when it's cold. The only way to use that SOL bivy would be as a vapor barrier, inside your sleeping bag and over only a base layer. You probably don't want to do that unless it's below freezing. As mentioned, though, it's a good emergency item for your winter day pack.

If you're doing anything but midsummer camping in the Cascades, you probably want a warmer bag. A couple of years ago, while I was on a trek up the Entiat Valley for my annual larch "fix" at the beginning of October, the temperature went down to 15*F each night. I was wearing all the insulating clothing I own, plus a vapor barrier suit (the latter under my insulation), inside a WM 20*F sleeping bag. I was warm enough on top, but my sleeping pad was insufficient so I was shivering underneath! I've seen freezing temperatures and small amounts of snow in the high alpine areas of the Cascades in early July and late August.

When I tried a silk liner, I got so tangled up in it (I toss and turn a lot) that it took almost 5 minutes to get out of my sleeping bag in the morning. When I ditched the liner after acouple of nights of that nonsense, I noticed no difference at all in the warmth of my sleeping bag. Your Mileage, of course, May Vary, but I've seen/heard the same complaints from many others. You're better off to wear more insulating clothing inside your sleeping bag and forget the liner.

With a full length zipper on the sleeping bag, or with a quilt, you can ventilate enough to be comfortable with a 20*F bag even on warm nights. There have been a few warm summer nights when I started the night on top of my 20* sleeping bag, but by 11 pm I was inside or under the bag and by 2-3 am I was at least partially closing the zipper. Nights cool off fast at 4,000-6,000 feet, or on the Olympic coast.

My understanding is that M50 is more breathable than M90. Am I wrong in this? (I'm sewing up a bivy with M50, so this would be good to know.)

If you want a bivy as light as 3.? ounces, check out Jamie Shortt's 0.51 cuben and M50 bivy. I bet you could find someone to sew it up for you (John West?) if you didn't want to do it yourself.

Here's the thread:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=44617&startat=20

my understanding is that m50 is more breathable than m90 (but not quite as water resistant)

I have a Gooses feet down Parka which uses m90 and it's extremely water restiant, no experience with m50.

Current m50 is much less breathable than current m90 as seen in my shop. I have a bunch of fabric and m50, 7d and old m90/intrepid are all not breathable enough to use with our down blowers. They fill with air and pop at a baffle seam. New m90(not similar to old stuff at all) 1.1 rip and 8d all are breathable enough to use with 8d being the most breathable (may be different soon not sure). This has been my experience.

-Tim

not fair that they're changing fabrics :)

Tim- is there are a way to tell "old" m90 from "new" m90?

Tim,

When did "new" M90 replace "old" M90. Were you given any change in the description of the M90 fabrics?

On 3/30/11 I tested samples of TG Intrepid, TH Momentum 90 MR, & Quarktex (20d) mini-ripstop. The CFM, HH, and micrographs were identical. Is TH the only company that radically changed their fabric characteristics without changing the name?

Basically that old 20d (many names same stuff) is gone. Nobody has it anymore that I can find. Not sure when TH got their 'new' supply but I think it was when they added all the new colors a while back. I tried the new colors when they came out and it was different. I ordered a 100yd sometime around the 1st of this year and was surprised that it wasn't what I expected. I asked and was assured it was just a different run of the same fabric, but it doesn't have the same properties.

I actually like the 'new' m90 better as it breaths more, still very comfy but maybe not as durable with less coating.

I am hoping to have some new stuff in this class that will breath better but still offer splash and wind protection. I tend to preffer more breath ability so I have to beg the guys sourcing the fabric not to coat it too heavy as others seem to want it more 'everything proof'. I am sure I will get what I need someday. Right now my favorite quilt fabric is 8d, new m50 looks just like 8d but with a heavier coating and less breath ability. I love the 8d hand too but it isn't 'proof' enough for bivys

-Tim

i have been told exactly that too that current m 50 material is not as breathable as the current m 90 obviously this is true according to our expierience with the two materials and we were in damp conditions to start with so i would have figured it would have been worse but the m 90 was almost completely dry just a little condensation at the beginning of the mesh and just a tad in the footbox but not enough to soak the outer shell of my alpinlite

kevin

thanks everyone for the help. i am starting to lean more in a different direction after all of this. I am having to do things that both benefit my Army life and my recreational life, so my decisions lean toward multi-functional in that regard. i started a new thread based off what i learned here. im hoping i dont need a bivy while being under my tarp.

new thread here with more questions if you all would like to help there too.

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=64011&skip_to_post=547703#547703

So Tim, what would you recommend for a bivy top to balance breathability and splash protection? I picked up the M50 thinking it was more breathable (my preference), with lighter being a nice side benefit. But now I'm rethinking the choice.

I guess I am not choosing fabrics for their performance in bivys but in quilts so what a bivy needs hasn't been on my radar. I think 7d is the most breathable of the still highly wind/water resistant options. I know new fabric options will be coming soon and I think you'll be happy with the options, I am just not in a place to spill the beans just yet.

-Tim

http://www.youtube.com/watch?v=ObH-y0s8RaY&feature=related

i inadvertanly stumbled across this video, he is doing what i mentioned, except with the USGI patrol bag (which i currently use). he didnt mention any moisture issues, although that isnt saying he didnt have any, i just note it as an unanswered question to me while watching his video.

We tried a similar settup a few times using synthetic bags. There is condensation but its not such a big deal on a synthetic bag (I think it would have been very bad on down). I don't consider it and ideal set up especially long term but for one or two nights its okay and it does seem to add some warmth but probably not as much as he claimed in the video. Also remember that as you get tired your body won't keep itself as warm. When I'm really exausted and weak after a hard day I sleep colder.