Companion forum thread to:

Marmot Atom Sleeping Bag REVIEW

I recently purchased an Atom - regular length. It weighs in at 1 lb 3 oz and a little over 20 ounces including the stuff sack. I, also, am a little disappointed in the extra weight.

Since the Atom has a partial zipper vs. the Western Mountaineering Summerlite, the Summerlite is fully baffled vs Atom's sewn through construction, and the two bags have about the same loft I wonder where the weight difference is? Is it the Atom's fabric or a lower grade down?

Don's measurements of the Marmot Atom and the Western Mountaineerig Summerlite:

Atom:
weight advertised: 1lb 4oz
weight measured: 1lb 6.6oz
loft (single layer shoulder & hip): 1.9 in
loft (above footbox): 16 in
fabric: Pertex Quantum N-090 ripstop shell Pertex Quantum N-090 taffeta lining

Summerlite:
weight advertised: 1lb 3oz
weight measured: 1lb 5.4oz
loft (single layer): 2.1 in
loft (double layer shoulder & hip): 4.1 in
loft (above footbox): 16 in
fabric: 0.9 oz/yd2 (31 g/m2) Extremelite 20D nylon shell


Summerlite Review:
http://www.backpackinglight.com/cgi-bin/backpackinglight/western_mountaineering_summerlite_sleeping_bag_review.html

Edited by pappekak on 03/21/2007 09:40:02 MDT.

Well, I can't say for sure without cutting up my bags (and that is NOT going to happen - not even for BPL!).

I believe the lighter weight of the Summerlite comes mainly from a combination of shell fabric and down. And remember the difference in weight is only a little more than an ounce in the size large.

I think both bags have high quality down - but I wouldn't be surprised if the Summerlite has less down than the Atom, even though it has higher average loft. The baffles add cost and complexity to the Summerlite. But I think they also allow the down to loft more consistently, and hence may allow a bag with less down to have a higher average loft. I think this may be particularly important in very light bags such as the Atom and Summerlite. The baffles improve the ability of the down to be effective for the least amount of weight.

This is a great sleeping bag... it is what it is... a sewn-through down bag. That means it is less expensive and has limitations. The extra weight is a disappointment. I'll weight mine and post the results.

This has been one of my favorite bags. The hood on it cannot be beat IMHO. I have had it down without any base layers to 40F and with light base layers to 36F. Mine weighs in at 18.6oz for the regular. I could cut tags, shorten sinch cord length but at 18.6 oz, why bother. Another great feature is the 62" girth. You can layer a bit under it and not feel too cramped.

Edited by johnatha1 on 03/22/2007 21:20:25 MDT.

Earlier, Steve asked why, with the extra features (full zip, baffles, etc.), the WM Summerlite weighed less than the Atom. The shell material and down (quality and/or quantity) could be part of it, but the cut of the bag could also be a culprit.

Reading the specs, it appears that the WM is a slimmer fit than the Atom. I don't own either the Atom or Summerlite bag, but I know from crawling into the Marmot Hydrogen and Helium in the shop that they are roomier than most of the comparable WM bags. I prefer the WM bags to the Marmot, if they fit; if they didn't, Marmot would be my first alternate. (For what it's worth, I ended up with the WM Mitylite and Megalite; the other bags I tried in the Extremelite series were cut too tight for me.)

Edited by garkjr on 03/23/2007 10:33:47 MDT.

Very good point Glenn. Certainly the different cut plays a big role in the relative weight of the Summerlite and the Atom.

Based on the comments so far, it looks like Atoms are generally coming in about 2.5 ounces above the specified weight in both regular and long lengths. I think Marmot would be much better off with a more accurate spec weight - thereby not dissappointing weight conscious buyers.

As I own an Atom, I think the review here on BPL is right on.

However, my email concerning this article contained the following description:

===================================================================
Marmot Atom Sleeping Bag REVIEW
-------------------------------------------------------------------

Backpacking Light staff discuss how to get the most out of any winter
trip from day trips to multi-day expeditions.




==================================================================
I eagerly clicked the link to read how the author used the Atom for winter trips, and I really don't see this type of information contained in the article.

For the record (since it is a complaint of mine, too, but my Helium suffers the same weight difference from the published weight), my Atom is 18.5 oz for the regular length.

Edited by bianchilvr on 03/23/2007 14:24:31 MDT.

Michele -

Yes, we had a blooper in the email this week. Sorry about that. We do have more coverage planned regarding winter outings - just not last week.

Don

Yep, Michele, you caught us! Stay tuned for the winter article referenced in that tantalizing description - it should be coming within the next week or two.

Unusual, i.e., not mainstream techniques, interest me most--my fav article was the one on hiking in sustained, cold rain a few months ago.

I can't wait to see what y'all come up with on this one!