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Hollow Socks Review: Biking With Alpaca Wool Socks.

Hollow socks are headquartered and designed in Wisconsin and manufactured in North Carolina. Their socks are made of alpaca wool, nylon, and spandex and come in black and gray. Here we share a review after using them gravel biking this summer.

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Meet Hollow, alpaca wool socks from Wisconsin

Hollow is a Wisconsin-based performance sock company that uses alpaca wool to improve comfort, dryness, and breathability. Designed in Wisconsin, they're all made in the USA in North Carolina. Their lineup is pretty simple and includes no-show, ankle, crew cut, and boot cut and are all available in black or gray.

When I was recently riding the Valhalla Beach Party bikepacking route with Dave Schlabowske, he mentioned that he usually buys Wisconsin-based socks. He was wearing some gray boot-cut Hollow socks and I figured I should get a few pairs of my own to try out and share with more up-north adventure cyclists who want to support a local company.

Alpaca vs merino wool for socks

Wool socks are often made with merino wool. Merino is antimicrobial and breathable which makes them great for long, warm activities like hiking and biking.

Hollow makes their socks exclusively with Peruvian baby alpaca wool (usually around 45% of each sock, with the rest being nylon and spandex). Alpaca wool is a finer, softer, and less absorptive wool than merino well which leads to some improved benefits that we'll break down here.


Alpaca wool is a physically finer strand of wool. The microscopic fibers are less pronounced and more uniform. This makes them smooth and incredibly soft. Merino can sometimes feel itchy where alpaca wool is predictably smooth.


Alpaca wool can hold 8% of its weight in moisture where merino can hold 30% of its weight in moisture. Both types of wool are great at moisture-wicking and resisting odor but alpaca is going to dry faster since it absorbs less moisture to begin with.

Overall Strength

Without getting too nerdy, alpaca wool has a higher tensile strength (~50 N/ktex) than merino wool (30-40 N/ktex). This means it can put up with more abuse and last longer, depending on construction and other materials used of course.


To be fair, I couldn't find any hard number on this one. What I did learn is that alpaca fibers are hollow (hence the name "Hollow" socks) which means every single strand contains trapped pockets of air for insulating. Merino wool on the other hand traps air between all of the microscopic protrusions in the fiber, but it's not hollow. Due to alpaca wool's hollow-ness, my findings seem to suggest that it insulates heat better.

Hollow socks on & off the bike, up north, in the summer

I've been using Hollow's black no-show socks (43% alpaca wool) and gray ankle socks (46% alpaca wool) on a lot of my longer rides this summer. Here are a few of my thoughts:

Off the bike

My first impression was that they fit perfectly. I have small feet (size 8) and got their size 8-10 socks. Usually when my feet are on the low range of the fit, they're always a little too spacious. But these have a great stretchiness that hugs my feet really snug. I wore them around the house, in the yard with no shoes, several days without washing and they're always nice and snug even without a fresh wash.

They almost have a luxurious feel because the fibers are so fine and they just glide right into my shoes or slippers.

On the bike

While biking, I never really noticed them. They stayed cool and dry on extremely hot summer rides. They also never felt sweaty or sticky when I was done. Again, they kind of feel a little lux because they're so smooth to the skin and on whatever you're walking on. But I like that they don't look silky. I prefer the gray color; it looks just like a traditional tough wool sock but wears more comfortably than either my Smartwool or Darn Tough socks.



  • Extremely comfortable

  • Stay dry and don't smell

  • Strong and snug construction

  • Designed in Wisconsin

  • ​Only available in black or gray

  • Somewhat expensive ($20-$35/pair)

Review Wrap-up

I don't think I've ever had an alpaca wool clothing of any sort. And to be fair, I haven't used these in the winter yet and my feet tend to get cold in even the warmest boots. But the no-show and ankle socks performed really well for hot half-day summer rides. To learn more or pick up a pair for yourself, head over to




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