Thinking of ditching WM Ultralite 20 for ZPacks 20 Bag. Good idea or not?

Question to ask yourself is how much do you use the hood.
And consider that the ZPacks bag is Extremely slim cut. I am a small guy slight of build and it feels very tight on me even without wearing a down jacket inside for added warmth in colder weather.
billy

Ultralight. keep it. You love it. That Z pack bag is skinny. Bet the temp rating is more conservative on the WM bag also.

Loft is not the same as WM bags.
Duane

I recently switched from the WM versalite to the zpacks 20.
I echo others comments about being slim, less lofty, and no hood.

However….the 1lb of weight savings made it totally worth it for me. So I'm very happy with it despite the few drawbacks.
I used it in the snow in yosemite a few weeks back, and can't explain this exactly, but I don't notice any difference in warmth compared to the WM…
Didn't test side by side though…so take that for whatever it's worth.

Random thoughts:
1. If you get the zpack wide (21.3oz), you’ll have slightly more room than WM.
2. However, I don’t mind the regular (tighter?) one. I stay warm enough with just the Teramur long johns on. Less space to warm up.
3. You will need a hat/balaclava. However, I appreciate this in the morning because I just keep on wearing my head gear until the day warms up. I wear a balaclava in mummy bags anyway to keep hair oil off the bag.
4. WM is nice. But it’s hard to go back when you’re losing 31-21.3 = 9.7oz (if going wide)
5. I think the zpack quilt will cover a wider temperature range w/o burning you up; i.e. 20-60F.
6. the zpack packs smaller (6×12 vs 7×13)
7. I have 4 WM bags and I sometimes will snag a zipper. I haven’t snagged a zipper on a zpack yet. Maybe because the smaller teeth make it harder to chew into the material.
8. Don’t sell your ultralite yet. Try both and see what your body can do.
9. If money is tight, JRB’s Hudson River Quilt (21.5oz) is on sale for $225. I find it as warm (20F) as the zpack but it’s narrower. You will have a gap under the back so a nice warm pad is required (not as critical with a zipped up zpack). Or the Hudson River with a poncho-hole (actually called the Sierra Sniveler @24oz) makes it convenient to leave your down coat at home. Just wake up and wear your quilt in the morning.

Anyway, just more ingredients for the stew,
May your dreams be of mountains,
-Barry

I have the Montbell ULSS#3 Long which weighs in at 1.5lbs. I find that it is the best compromise of comfort and weight for me for three season backpacking here in the PNW as most of my trips during those months tend to stay above 40*. I've found that sleeping with insulation/rain gear on and in a bivy can add another 10* to a bag's rating for when the temperatures drop below that but full disclosure, I haven't owned the ULSS#3 bag long enough to say how it'll do in temperatures closer to 30*. Like shoes, sleeping bag warmth is highly personal and as a result, my experiences may not mirror yours.

Just wanted to add some food for thought that maybe you might not need a 20* bag but you know best.

I have no experience with your sleeping bag or zpacks to say how those two compare.

ymmv etc etc

I had a WM Ultralite 20 Long and changed to a Zpacks 20 XXL/XW about 6 mos ago. The WM is a terrific bag, but I wanted a little less weight and the hoodless design. This is how they stack up for me:

Warmth – WM Ultralite
Construction quality – WM Ultralite
Longevity – WM Ultralite

Price – Very close to a tie.

Premium materials – Zpacks
Weight – Zpacks

Ryan

11 oz saves a fair amount of weight, but its also a pretty big item to replace without knowing if it'll work for you. I've owned WM & marmot bags that I loved, but switched to Katabatic quilts a couple years back. with my sawatch, I saved about 8 oz, and added I'd guess about 10 degrees of warmth over my marmot helium. It also saves considerable room in my pack which has become more important as I've picked up skiing & packrafting.

I think if you've got a compelling reason to shed the weight (more miles, scrambling, multi-sport, longer unsupported trips, more wine etc.), then switching to a Katabatic, EE enigma or zpacks would be well worth the weight savings. Its different for everyone though, and certainly WM is some of the best kit around.

Appreciate all your input guys. Tough decision it seems. Clearly sounds like the WM is warmer, and if I go the wide on the ZPacks that gets rid of the width difference and is still 10oz lighter. I do tend to sleep quite warm. Then it comes down to hood vs no hood and comfort.

Is there a noticeable difference in comfort between the two?

That zpacks bag has a lot less fill weight than the western mountaineering.

"I'll be doing the majority of my hiking 3 season in the PNW."

Off on a tangent, the Ultralight is a lot of bag for 3 seasons in the PNW. You could trade down to a WM Summerlite with 2 oz of overfill and have a bag with hood that would take you down into the low 20's using it in conjunction with your clothing, for only a 2 oz weight penalty over the Z-Packs 20 bag. That is all the protection you'd need for 3 seasons up here. My 2 cents.

Yeah, if you sleep warm in PNW 3 season, then you could save even more weight & go with a 30 degree zpacks Katabatic or EE.

As far as hood/hoodless, I wouldn't use a quilt without a hooded puffy jacket or a seperate down balaclava. For comfort, I prefer a hooded jacket, assuming a good hood.

You guys are definitely right, I don't really need a 20 degree bag up here I guess, except when I go out for some winter camping every now and again. Maybe I should keep this and look into a higher temperature bag to save some weight when I don't need the extra heat.

I have a Feathered Friends 20 and a Zpacks 30

I haven't done a lot of testing, but I suspect the 30 is as warm as the 20 (except for the lack of hood) due to fitting so snug with less air to heat

b

I am not sure if you plan to get out in winter, but if you do it may be worth keeping the Ultralight and purchasing a 30F quilt for summer use and then use the two together for winter.

If that's not the case you should keep the Ultralight until you are happy with your new purchase (if you can afford to do so)

Good insights in this thread. I, too, have been considering buying a ZPacks bag to replace my WM. I appreciate all the comments in here, it gives me something to mull over before I do it.

I have a zpacks long, wide 20F bag and it's certainly not nearly as lofty or substantial feeling as my marmot helium. For it's weight it's a fairly warm bag but I think a lot of the temp rating is zpacks having a close fit. I'm a small guy at 5'5" and ~ 160lbs and didn't want a super tight fitting bag which is why I ordered up. The downside is that I don't think the bag is a 20F bag for me but it probably would be for someone larger.

All in all I like the bag, mainly for it's weight or lack thereof. I think an overstuffed Western Mountaineering Summerlite would be a decent alternative and is one I may consider in the future. One thing that I do like which I thought I wouldn't was the lack of a hood. I slept very well in it over the weekend along with my monkey pillow.

Edit: I really like my zpacks bag and was very warm in ~ low 30's with one exception, my feet were a little colder than I'm used to but as I mentioned, I think that had a lot to do with the bag being long on me.

I have used many different WM/FF bags, and a couple of ZPACKS now. I landed on the ZPacks 10 degree, Long/Wide with 900 fill. It weighs 23.4 ounces, and I was just telling some folks this weekend it is my favorite piece of gear in my kit.

I love the loft, warmth, weight, and freedom of the quilt-like config and would never even consider going back to WM or another std sleeping bag. I can snuggle inside and zip up when chilly, or unzip and leave legs out when hot, it doesn't get more versatile and I have not missed the hood at all, especially when unzipped as it lays nice and flat.

I do use a sleeping bag (a -20 MontBell expedition bag) in the dead of Winter, high altitude, but use my ZPacks bag every other time.

In my humble opinion, Zpacks is a great bag and a really nice alternative.

For the Zpacks bag owners, how's the foot box or what appears to be a lack thereof working out for you? Any issues with down compression due to the design?

I had a zpacks 20 and I tested it against the FF Vireo 18 oz at about 28 degrees in the snow without a tent for a few hours.
I wore a WM Flash jacket. I was warmer in FF Vireo especially the footbox so I kept the Vireo. I still have a zero degree zpacks bag that is very lofty but it has 22 oz of down.

I found the dwr water resistance on both the zpacks and Vireo Nano to be excellent, no need of a bivy to keep off splash and dew.

Also a zpacks wide is probably equal to WM ultralite, the regular will be a much tighter fit.

Ian,

My Zpacks bag is actually a little long. If it fit like a normal bag I can definitely see the down being compressed in the footbox. I think it's designed for side sleeping only.

Ryan

Thanks Ryan that's very helpful. I'm more of a kung-fu sleeper which has kept me away from quilts in general but I was contemplating buying one of these bags and using it like a hoodless Nunatak Sub Alpinist where the zipper/draft tube would be on top. Since it'd only come to my shoulders, I could get by with a 6' bag but the foot box looked problematic and, based on what you've written, I'd probably have to go up a size in length.

I echo what Ryan mentioned about the footbox, I tried one out a couple of years ago and my size 12's compressed the down when lying on my back.

I think they may have improved the foot box from a couple of years ago… best to ask Joe at zPacks…

billy