Fellows,
I backpack often in winter in the hills of PA and West Va. I have an old, heavy down winter bag and wanted to replace it with a nice, light WM bag. Which one?
The nighttime lows are around 10F but can drop to 0F or maybe -5F. I sleep fairly warm.
I use my campfire clothes over my usual light daytime backpacking layers for sleeping: MontBell Alpine Lite jacket, Cocoon Pro hood, MontBell Thermawrap insulated pants, down booties. Warm platypus inside.
Big Agnes insulated aircore (full length mummy) & GG nightlite torso + pack under legs. Tarp, no tent. Below treeline, fairly protected campsites.
A friend uses a similar scheme with a WM Megalite (rated 30F) which surprised me.
Alternatives are WM Ultralite (narrow) or Alpinlite (wide) both 20F, or Versalite (between above 2 in width) 10F.
Anyone have experience with these and could offer suggestions.
The Megalite is attractive as it is 5oz lighter than the Ultralite, 7oz lighter than the Alpinlite, 8oz lighter than the Versalite.
I'm 5'8", 160#. Would the Ultralite be too tight?
Lastly, a puzzle, why is the Megalite so much lighter than the Ultralite & Alpinlite for a 10F difference, whereas those two are only a couple of oz lighter than the Versalite for another 10F difference?
Thanks for any suggestions.
Marty Cooperman

