Just Jeff's Hiking Page

"Going to the woods is going home, for I suppose
we came from the woods originally."

- John Muir

Zippered Segmented Pad Extender

Looking for a better cold weather solution. I really like the DownHammock for three season trips, and it's more comfortable than sleeping on a pad, but I don't want to go into true winter conditions without a pad so I needed a way to incorporate one into my system. I really like the SPE concept from Ed Speer and Youngblood, and my homemade SPE works pretty well...but how else could I improve it?

I wanted a way to zip my winter bag onto it so I wouldn't have any drafts. So I combined the Big Agnes system with the SPE and solved a few problems. I basically made a pad sleeve, then sewed on a zipper to match my Wiggy's sleeping bag set, then sewed on the SPE wings.


  • Any bag can be used if it has a separating zipper. You just need to find a zipper that matches your bag.
  • The bag doesn't lay between me and the pad, which has always given me condensation problems in a hammock.
  • Since I'm basically extending the girth of the bag by the width of the pad sleeve (18" in this case), the bag is big enough to drape all the way around me, almost like a quilt, and it doesn't have the air gap problems of the Big Agnes bags.
  • There isn't a draft tube on one side, but the SPE wings fold up to eliminate the zipper drafts down most of that side. (The bag should be big enough to drape down and eliminate drafts but I haven't tested this yet.)
  • Just like the SPE, I can adjust how many pads I put into the sleeve. I'll probably use my Exped Downmat 7 and a CCF pad for winter conditions. But I also have two Wiggy's bags that can be used separately or zip together - so now I can put a 35F bag, a 0F bag, or a -20F set on this SPE mod. And if I need to go to ground (ick...) I'll still have a full-on sleeping bag instead of a BA top bag or a quilt. That may be important if a winter storm hits unexpectedly.
  • I can put my headlamp and other odds and ends into the sleeves and know where they are in the morning.


  • Total weight is 7 oz (200 g). A lot of this is in the zipper b/c Wiggy's uses a big heavy duty zipper...it would be much lighter if I made it for a Western Mountaineering or similar lightweight bag.
  • The pad sleeve is 18.5" wide by 59" long.
  • The wings have a 16" circumference, so they should hold a pad that's ~7.5" wide and 1" thick, or more likely 7.5"x.5", with my rain gear or extra clothing behind it. They're 38" long, which reaches from my shoulders to my knees. I'll still put two pads into them like the original SPE and they'll be able to fold with the hammock. If they're sized right, there should be some overlap so I don't get any cold spots.

Here's the SPE Mod on a ThermaRest. It's just a SPE with a separating zipper that matches whatever sleeping bag you have. I didn't see a reason to put an upper and lower wing like the real SPE - it works just as well with one tube.
Close-up of the wing. I put some elastic in the wing's hem to hold the pad in.
And a close-up with a pad inside the wing and the bag zipped on.
The back side of the SPE Mod. The real SPE uses spandex here, which would work MUCH better than the elastic. My fabric store didn't have anything like spandex so I grabbed some elastic for this prototype.

I think using the elastic like this causes bad drafts, though. It lets the material bunch in places and pull off the pad in other places, so the only thing between me and the cold air in those places is the layer of DWR. Spandex should keep the DWR in contact with the pad along the entire length, eliminating drafts from underneath. I'll test this before I hit really cold weather.

Close-up of the back side to show the flap of DWR on the back side of the pad. I put the elastic on this flap, but next time I'll use spandex.
Close-up of the bottom of the zipper...this is where I attach the sleeping bag to the SPE Mod. I meant for the whole sleeve to go all the way down instead of making the "V" at the bottom, but I guess I measured wrong. Next time...
The bag zips onto both sides like this, turning any bag into a Big Agnes-style setup.
And with the bag zipped completely onto the sleeve. The opening is pretty big, but it snugs up nicely when I pull it around me. I can either push the hood down inside, or lay on my side and wear the hood.

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