While I love wool -- especially a wool/poly blend. For a base layer on the really cold days, I find this layering preferable. Base Layer: Silk Long Sleeve Underwear Tops (this stuff wicks, it dries fast, and is very lightweight so you don't feel like you have so many layers on), then I use my Long Sleeve Wool/Poly Jersey (40%/60%), and then some sort of wind proof jacket (with lots of venting zippers for when I'm climbing).

Seriously, check out the silk stuff (you may want to check the Ski section of the store, that's what I originally purchased it for).

What this forum/thread needs a good dose of HTFU

There is being a little uncomfortable, then there's being completely unprepared. If you aren't one, you are the other.

I have more of those than I can count. They're wonderful. IceBreaker and SmartWool aren't any better at all, just different.

Wool is great stuff but in my experience any generic polypro shirt is going to work just as well, be far cheaper, more durable and easier to wash. Personally, I like the $25 Helly Hansen shirts: tight fit, long arms for good coverage, smooth finish, and they have sweet chevrons on the sleeves. I have about twelve of them.

It's a base layer. Its job isn't to keep you warm, it's to wick moisture (sweat) away from your body. Your insulation layers are the ones that are there to provide insulation.

So then any particular reason you clipped off the rest of her post where she described her system (including merino insulating layers)?

I have a LS silk base layer and I hate it. I find that it's hot and doesn't breathe. REI's article on layering says:

"For outdoor comfort, your base layer should be made of merino wool (popularized by brands such as SmartWool, Ibex and Icebreaker), synthetic fabrics (such as REI MTS, Capilene, PowerDry and CoolMax polyester) or, for less-active uses, silk."

I suspect the "less-active use" qualification has to do with silk's less than ideal breathability.

....not evaporate due to the non-breathable wind jacket?

Don't worry--we have a thread for that too:

https://www.bikeforums.net/showthread...-winter-jacket

I don't care how well a jacket breathes. Cotton is not a good insulating layer for aerobic activities.

I think this sounds right. I have a silk baselayer that will get soaked on hard rides. Not as bad as cotton, obviously, but it certainly doesn't move moisture out the way polypro or wool does.

I found some "cold gear" brushed shirts similar to underarmor on ebay for $20 each. they're pretty nice as a base layer.
https://www.ebay.com/itm/Compression-...item2c6499edeb

UnderArmour can work great in some instances. I've used the Cold Gear tops but like you said when they get wet they tend to stay wet and that sucks. I have had luck with the all season long sleeve. Not as thick so itmay not keep you as warm but I feel it does a better job of wicking.

So, what's my jersey for then? And how does another layer, doing the same job, not make you warmer, not cooler? I know different things work for different people, but the math doesn't work here.

I have always just gotten a jersey that fits right (tight) and that keeps sweat from building up. I never have sweat dripping around on my torso -- it's wicked and evaporated. I see no way that a base layer could possibly help. Maybe more people are wearing jerseys too loose to use for this purpose?

Note that I ride in a very warm climate that goes from humid to moderate, and I've raced many times over 105F.

I'm sure some of you know this. But for those who don't here is some general information on how this stuff is supposed to work:

Polypropylene is the most hydrophobic synthetic material commonly used in athletic clothing. It also has a low re-activity to most chemicals, UV light and electricity. On a microscopic level the individual fibers are fine but solid. As a base layer it works by fitting close to the skin where it's hydrophobic properties force sweat away so it doesn't evaporate on the skin which would pull heat out of your body. The 'stink' factor is created by it's non porous oleophilic nature which which attracts body oils and dirt to it's surface and creates a breeding ground for bacteria. Most of this is also true for polyester, but to a lesser extent depending on exact make up and treatments.

Merino wool is the most hydrophobic natural material commonly used for athletic clothing, although it is not as hydrophobic or unreactive as polypropylene. It does have textured, spring like fibers (think fusilli pasta), though, that use capillary action to pull moisture away from skin. They also due double duty by holding their shape even when wet which is why wool is still a good insulator when wet. But merino does not generally dry as fast as polypropylene of the same fabric weight due to the shape holding a bit of that water. Wool does have natural anti-microbial property which tends to keep BO down.

Cotton is hydrophilic. When in contact with water it soaks it up and tends to hold it taking a long try to dry. This also causes it's structure to collapse and loose it's insulating properties.

But that said, there are a myriad of different people and riding conditions. So try some of this stuff yourself. As I said earlier, I personally like wool as long as I am not wearing a highly wind resistant outer layer. But if conditions warrant using a windproof jacket I switch to a thin, body fit synthetic base and then layer in between as needed.

If you are only wearing a jersey then it is functioning like a base layer - transporting moisture away from the body. If it's hot you don't need an insulating layer. Instead, you want clothing that will promote the body's natural evaporative cooling process which is what a close fitting jersey will do. When it's cold, the base layer does the same thing - moves moisture away - but now you want to hold onto the heat so that's what the insulating layer is for.

What some people don't realize is that a base layer can actually keep you cooler on hot days by enhancing the evaporative cooling process. My merino base layer will get damp and as air flows through my jersey it helps to cool.

Merino doesn't wick ... it absorbs.

since i assume people wearing merino wool here buy it from an athletic/sporting company

https://www.wool.com/Wearing_About-Me...of_Wicking.htm

". Merino fabrics manufactured from fibres that have not been chemically treated do not tend to wick water or only very poorly."

but then...

"If the lipids are removed by processes such as chlorination or oxidised by plasma treatment the fibre surface becomes quite hydrophilic. Merino fabrics treated in this way wick water quite well"

Not sure what your beef with wool is but your comment shows incomplete understanding of how wool works. While wool does absorb some water it keeps it away from the skin. Despite the fact that it absorbs some water, it's ability to manage moisture is still considered excellent as are synthetics.

https://www.rei.com/learn/expert-advice/underwear.html

The beauty of wool is that it works at both ends of the temperature spectrum to keep you warmer in winter and cooler in summer. It's also natural, antibacterial, and sustainable.

Everyone should try various fabrics and determine what works best for them and their particular climate, but to argue that wool can't or shouldn't be used as a base layer is silly given that many people find it very effective. After rides in hot and cold weather, hikes and snowshoeing trips using wool I have never once felt wet or cold even though the base layer is often quite damp feeling when I remove it. What's interesting is that I can put this damp feeling shirt back on and it feels both warm and comfortable.

This is a nice article explaining the properties of wool and synthetics as well as some field test comparisons.

https://www.backpackinglight.com/cgi-..._clothing.html

Absolutely no beef with wool. I love the stuff. I own lots of wool items and wear it in all sorts of conditions from temps as high as a humid 26C down to a chilly -40C/F. I wear it for cycling. I wear it at work as office wear.

It just doesn't work particularly well as a base layer.

As mentioned earlier, I tried and tried to use it as the base layer, then polypro over it, then fleece ... no luck. I was soaked and uncomfortable. Then Rowan was the one who suggested I switch the polypro and wool, so that it was polypro as the base layer, then wool, then fleece, and it worked very well. I was dry and comfortable, even on my winter centuries.

I have both merino wool and synthetic base layers, but I prefer merino wool mostly because it doesn't stink anywhere near as much and dries easier, as long as it's not a super thin weave. I think just like any other material, there is variation between merino wool garments - different thicknesses, fit, weave, % wool, etc. My favourite is my Capo merino wool polo. Looks good on and off the bike, and feels comfortable. I usually keep the synthetic layers for more temperature days where it's warm enough that I don't mind wind drying off my sweat.

Just a follow up. Shortly after starting this thread I came across a pretty good deal on a Craft Pro Warm long sleeve base layer on Ebay. Today it was 40 degrees in PA with a NNW wind @ 20 - 25mph. Not real cold but with a solid artic wind bolwing it was chilly. What a difference between the UA and Craft base layers. The Craft base layer hands down outperformed the UA. It wicked and dried much better (didn't retain water like the UA) and was just a warmer and much more effective & comfortable base layer. I guess you get what you pay for ... well worth the few extra bucks it cost. I'll be keeping an eye out for other Craft deals on Ebay. Two thumbs up on Craft clothing.