View Full Version : Shortening a Long Down Bag

03-03-2014, 12:39
So I got a killer deal on a sierra designs pyro 15 long. I bought it on a whim because that low of a price was the only way I could afford a decent cold weather bag. However, it's a long bag and I'm only 5'9", so there is a decent amount of dead air in the feet area.

I tried the bag in the backyard on a zlite +pro lite pad combo and it was still toasty down to 18 with just a poly base layer. But I was thinking about making some improvements.

I had the idea of taking it to an experienced seem stress to chop the footbox off and make a new one to shorten the bag. I'd then ask her to use the excess down to overfill the bag. Does anyone have experience with this? Would it be worth my time and $$. The zipper seems to be he biggest issue.

03-03-2014, 12:42
On closer inspection, it appears I could shorten the bag about 8" before the zipper starts at the foot end.

Wolf - 23000
03-03-2014, 12:58

Overfilling your bag does not always improve the bag. In fact it could result in you just carrying extra weight. Down works by how well it can expand. If the down can fully it is not doing you any good. This may or may not be the case. It really depends on how much space you have in your bag. Just something to consider.

I suggest maybe using it for a jacket or something.


03-03-2014, 13:15
Stuff a jacket or something in the foot end or try shoving the foot box back inside the bag to reduce the volume that you need to heat. On a really cold night, put a hot water bottle or 2 in the extra space. You risk ruining a perfectly good bag and its' resale value.


03-03-2014, 13:50
I've very recently done "surgery" on a down bag, worked great, I took a 45 deg. rated bag and increased the loft significantly by modestly overstuffing the baffles. I only added 3 ounces of down over the entire length, makes a big difference, adding at least 1.5 inches of loft (this is kinda hard to measure), and the baffles still have expansion room. If you are modest, you do not risk overstuffing IMHO (wolf's concern below). Here is my post for overstuffing:


As far as the shortening goes, that might be trickier, and I would definitely go to a pro for that because you do want good insulation left in the foot box area, and even on the vertical end, that might be tricky.

03-03-2014, 19:23
I operated on a 20* down bag I bought at an REI scratch and dent sale and added 4 oz of down to it but I would not do what I did to a new bag. I would use as is at least until the new wore off.