Insulated pants: Down vs Synthetic

You would be well served to add another layer the length of bicycle pants to protect not only yer butt but but the femoral arteries in the inside of your thighs. A lot of leg heat is lost there.
Eskimos often added fur knee length "shorts" in very frigid weather for this reason.

Personally I use sunthetic fill pants as a mid layer in frigid temps when winter camping but only in camp.

For really cold weather my alpine ski pants are GTX/Thinsulate with polar weight long underwear. Never been cold, even at -20 F. & 40 mph winds with that combo.

Cloudveil's powerstretch fleece boxers are fantastic.

Standard equipment for me when things dip into single digits.

My system was going to be what Mike C! described in his NOLS winter gear list; baselayer (Smartwool microweight tights, Powerstretch fleece tights, insulated pants, Marmot Precip shell pants

I'll have to look into those powerstretch undies.

If you are looking at insulated pants that would be considered lightweight (like 12 oz or lighter), none will have significant insulating ability when compressed under your bodyweight – down or synthetic. I have homemade polarguard 3D pants, and for seat warmth I rely on a nice foam pad. I just use my sleeping pad.

Just to echo the previous comment, it is really important to have a foam 'sitz' pad for winter activities. Here in the Yukon, we have them even in our day packs for walks in town—like today, when a shaft of sunlight broke through the overcast (lakes are just freezing now) so out came the foam pad and we plunked down on the sitz pad to grab 10 magic minutes sitting facing the sun!

For me, I have both down and synthetic overpants; the down ones stay packed as bike survival clothing, because they withstand compression better, whereas the full-zip Primaloft overpants get worn for -20 to -40C/F as they dry more quickly when entering a heated shelter.

Lack of compressibility is often cited as one of pile's drawbacks. I think this is pile's strength. If you're making insulated pants consider adding a layer of pile inside the seat and knees. Even though a sit pad is a great idea, the extra insulation will be nice.

Although synthetic filament insulation compresses less than down, it will still compress to almost nothing when you're sitting on it.

Different stuff, different uses. I would never wear down clothing with a pack on – the down would get too compressed and be damaged. But fleece is great for these conditions.

(OK, all bets are off when you are climbing Everest – but that hardly applies here.)

What is interesting is to read what some of the Antarctic travellers wear while moving: very little in fact! Some fleece/thermal stuff under a windproof outer layer. Try Mind over Matter by Ranulph Fiennes (although he is NOT a gear afficiendo and did some serious stuff-ups.)

Cheers

Roger,

I read Ray Jardine's blog about skiing to the south pole. He, and others mentioned, suffered frostbite on the front of his thighs. This was from spending long days skiing into a heavy headwind in cold conditions. They were wearing very warm puffy down pants. Unfortunately the wind pressure (and just the act of stepping forward) squeezed the soft down to nothing in front. I think that going with fleece pants and slightly thinner down pants would have been better. Especially since he wore them all the time the lack of compressibility wouldn't matter.

Here in California my issue is usally too much clothing vs. not enough. For active use in the winter (Temps 20F-35F) I'm usually comfortable with just a thin baselayer and wind layer. I carry a pair of side-zip pile pants for rest breaks or around camp. If it's too cold in camp I get in bed!

I thought Ray Jardine was totally against down hence his synthetic quilt. I have not read his blog though so he may feel different about down clothing.

Anyhow jim where did you get your side zip pile pants are they MYOG. When searching for side zip fleece pants I only find raingear or down/synthetic insulated pants

I have the advantage of starting backcountry skiing when I was 15- or almost 30 winters ago. My side-zip fleece pants are from "The Yak Works" probably 20 years ago. They're rather thick and heavy, but very cozy warm. I started out using them with a pair of zide-zip 3 layer Gore-Tex overpants. Most of the time going uphill I end up skiing in just long johns and the overpants. Unfortunately the overpants are not all that comfortable with thick zippers and snaps right under my hip belt.

I realized that the overpants don't really need full zips, so I switched to some baggy wind pants. When I need to add the pile pants I just drop trou and put the side-zips on, then pull the wind pants back up. Don't need to take skis off.

One drawback though of slippery pants is the near-fatal slide I took down 13,000 foot Mt. Goode one winter. But that's another story…

I think adding side zips to store-bought pile pants would be quite easy. Just rip the outseam and sew in a separating zipper. If you don't have the skills then somebody like Tim Marshall or SpecialtyOutdoors dot com could help you out. The biggest part of the work would be ripping the seam.

Here in the UK, Buffalo clothing make full side zip Pertex and Pile pants They also make bibs.