overbag over 3 season bag or winter bag for winter?

[twochordcool]

I want to have enough warmth for winter camping - do you think a fleece liner inside a 3 season sleeping bag inside an overbag is good enough, or is a winter bag vital?

What overbag would you recommend?

I'm trying to avoid spending a million dollars on a winter bag, especially since I already have 5, 15 and 20 degree sleeping bags!

[Kevin]

I want to have enough warmth for winter camping - do you think a fleece liner inside a 3 season sleeping bag inside an overbag is good enough, or is a winter bag vital?

What overbag would you recommend?

I'm trying to avoid spending a million dollars on a winter bag, especially since I already have 5, 15 and 20 degree sleeping bags!

I was in the same boat Fall '04 when I was gearing for the winter. I have an Outdoor Research goretex bivy, a zero degree synthetic EMS bag, and a polypro liner. Bivy adds weather resistence and maybe -10F of protection, the liner a solid -10F more of protection. I figure I'm safe to -20F which is the coldest I would ever intentionally stay outdoors.

$100 for the bivy, $150 for the zero degree bag, and $50 for the liner. I think I have a nice, modular -20F setup for $300. I've used 2/3 of these items in all seasons, so it's not a one trick pony like a true -20F bag would be. Only downfall is the additional weight. A -20F bag with some weather resistence would weigh less than the bivy and zero degree do combined. In the winter I figure I'm carrying 50lbs minimum no matter what, so another pound isn't going to matter as much to me as in the summer (when I'm back packing longer distances and want a lighter pack).

[twochordcool]

Well, I've seen bivy sacks and I've seen overbags, and it seems that they both do basically the same thing as far as warmth is concerned - perhaps with the bivy sack being a little more waterproof / water resistant?

I did a google search on "overbag" and Mountain Co-op (Canadian REI-like store?) has 2 come up - they claim to give you 10 degrees Celsius more warmth...

another thing that comes up is from "Wiggy" which looks great and is used a lot by the military - but I'm not very familiar with them either.

Anybody else have any ideas / suggestions?

[doug]

I've been toasty this winter in 5-degree weather in a 20-degree synthetic bag and an OR sleeping bag cover (waterproof bottom-breathable top). I also have a zero-degree down bag and a liner so figure that, in combo with the cover, would work for well below zero, but I don't think I'm masochistic enough to intentionally do 25-below

[redhawk]

OR Bivy or Sleeping Bag Cover, fleece or silk sleeping bag liner and a 20 to 0 sleeping bag should cover all your needs in the dacks.

I've only had one weekend where I actually had to use all three.

For multi day trips I also reccommend synthetic over down, preferring the xtra weight over the possibility of a damp down bag caused by perspiration and condensation.

[fvrwld]

We've had a lot of threads on this topic with some real good info. Here's one . I'll see if I can find more.

OK...here's more...

http://www.adkforum.com/showthread.php?t=1460

http://www.adkforum.com/showthread.php?t=488

Hope these help. There was another very long thread that discussed 0 degree bags and combinations but I can't find it.

[forevrwyld]

I have used a 20F down bag with a piece of fleece I bought at a fabric store as a liner and been toast in the 10 degree range.

Used this combo once (unintentionally when it was -15F) and I would not recommend it.

Purchased a 0F down bag that I haven't had the opportunity to try out yet.

'Ev (the other Forever Wild )

[twochordcool]

About that Outdoor Research Basic Bivy...

From pictures and descriptions on the internet I cannot tell whether or not it is available in a left-side zipper style and whether or not it zips all the way down or only partially -

I'd prefer a waterproof / breathable shell with a left-side zipper that zipped down the entire length - if I were to choose a bivy sack over an overbag.

[Kevin]

It's a left hand zip and unzips most of the way.

[JClimbs]

A few comments:
A layered sleeping 'system' may or may not work well, depending on a few important variables. The most crucial of these are loft and wind-resistance.
If the items you want to use together do not cramp each other's style by crushing each other and thus creating cold spots, you should be fine. If however, you have to work hard to stuff inner items into whatever bivy you're using, you will compact the insulation and thus reduce the effective insulating efficacy of the system.
Wind resistance is also very important. Try sleeping outside in a bivy one night and then, using the same sleeping gear without the bivy, in a good tight tent. Because wind hits your bivy directly when exposed to the good ol' outdoors, heat leakage is transferred much more rapidly (wind carries the available heat away quickly, in effect exposing new, cold air to the same area of your bivy: heat differential does the rest). So if you're planning on not using a tent, I would recommend rethinking that idea. Since you've got the bivy sack already, putting the whole system in a tent would probably net you another 10 degrees of comfort, if not more.
As has been mentioned, moisture is a major factor in winter comfort, though I'm not sure your particular system changes moisture retention/resistance much. Keep your sleeping gear as dry as possible (keep your nose and mouth out of the bag, for instance) and you will be much better off. If your layering system affects the moisture resistance of any one component, that would be another crucial consideration.

[Kevin]

A few comments:

Awesome! Thanks for the good pointers!

[twochordcool]

dilemma:

Every sleeping bag that I own is a left-zipper bag -

I can only find right zipper overbags and bivys..........and most only zip down half way!

Should I wrestle with stuffing a sleeping bag in a thing that only zips half way down..........and struggle with getting in and out of it?!

Er, or should I buy the 0 degree Sierra Designs Washakie at Campor for $99 and place a fleece liner in it?!

only problem: frost, moisture and "weatherproofness".

Is that even a word?!