I’ve been using the Smartwool Headliner Merino wool hat as a helmet liner for two winter seasons now. I bought it at full retail.
As you can tell from the name, “Headliner,” this hat is designed to be very thin so that it can fit under a bicycle helmet. I usually don’t have to adjust my helmet at all when I wear this hat, compared to my thicker polypropylene hat that I wear when the temperature drops below 35.
Wool is a terrific insulator, and works pretty well in both hot and cool settings in general. As a helmet liner, it starts to feel pretty toasty to me above 55 degrees, but I usually have a relatively warm head and warm hands.
Down to around 35 degrees, I found this liner to be warm enough. Once it gets below that, my ears don’t quite stay warm enough. For others who have cold ears or a cold head, you might want to adjust upwards 5 degrees from my usage.
The wool hat does not itch. It is made from Merino wool, which is a finer wool than standard wool. You can machine wash the hat. I wash it in cold and let it dry by hanging it out. I only wash mine every couple of weeks or so. One of the other great features of wool is that it doesn’t pick up stink. So even if I ride hard and sweat in the hat and put it next to my bike helmet to dry out, I can take a big sniff the next day and there will be no smell.
It features “single layer interlock knit construction, and a
contoured 3 panel design with clean finish flatlock seams,” as described by the manufacturer. I think what that means in plain English is that it is one thin layer of wool, sewn together in three panels so that it fits on your head right.
This would make a good hat for runners who want something really thin that won’t cause overheating.
The hat sits relatively high on your forehead, so it won’t impede your vision while cycling. The sides of the liner are designed to come down and just barely cover your ears, and that’s how it fits for me. I wear Adidas prescription cycling glasses, and I can either wear it with the glasses over the outside of the helmet liner, or under the liner.
If you read my wool cycling socks review, you might have noticed that my Smartwool socks made the bottom of the list in that review. But unlike those socks, I really like this helmet liner / super thin wool hat and fully recommend it.
Did I leave anything out? Have a question about this product? Do you own this product and like it or dislike it? Leave a comment and let me know so I can respond and update the review.