The DeFeet Thermeator Knee High sock is a warm, long option for winter rides where you might want extra snugness, but not run full tights. The high quality makes the price tag a sound investment in enjoyable winter cycling.
- Pros: Almost-merino warmth, length, padding where you want it
- Cons: Price, the scorn of the short-sock police
The DeFeet Thermeator Knee High was a new one on me. I’d seen full-calf socks used in orienteering events for protection from undergrowth while affording close-fitting warmth or cooling, depending on the season, but a relatively new add to my cycling repertoire.
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The Thermeators are knitted thick around the toes and forefoot/heel, then thinner around the front of the ankle for articulation. They then go thicker up the shin, before going thinner again over the calf. All this adds up to the right padding and insulation where you need it, with the right amount of compression to stay put (although these are not a ‘compression’ sock per se).
I found they kept my calves really warm on an autumn afternoon with temperatures around 8-9°C, wearing shoes with toe covers. Their warmth comes from the hollow-core Thermeator fibre, which is 30 per cent lighter than merino and dries and wicks water away instead of absorbing it as wool does.

The non-merino material might lose something in the ultimate warmth stakes but not much, plus they can go in a hotter non-wool-wash without issue.
Although £27.50 isn’t cheap for a sock, it’s not outrageous for a waterproof option, plus they work and durability looks good. Sealskinz’ Super Thin Mid Socks cost the same (and many others in its range are more like £35-£40), while Showers Pass’ Lightweight waterproof socks are just 50p less at £27. The Dexshell Ultra Thin Modal socks are cheaper at £22.
> How to keep your feet warm while cycling in winter
For the money, though, and if you can get your head around the sartorial leap, the Thermeators are a great choice for cold-weather cycling.
Verdict
A hardwearing, warm choice for cold-wet days out on the bike, on or off-road
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road.cc test report
Make and model: DeFeet Thermeator Knee High
Size tested: Large
Tell us what the product is for
Keeping your lower legs warm.
DeFeet says:
Mid-density thickness, no shoe fit compromise
Designed to keep your feet dry and warm
Creates a tighter fit in close fitting cycling shoes
Intended for athletes who love to ride outdoors, no matter what Mother Nature is throwing at you.
Providing warmth without the bulk of a traditional knit sock, the DeFeet Thermeator Socks are constructed from Thermolite fabric which offers breathable insulation and 30% less bulk than a equally effective knit sock.
This wonderful material is complemented by a durable construction. Mid-arch compression helps to support your foot while the quick dry vented Aireator mesh instep releases heat and moisture so your feet don’t get horribly stuffy.
Low-bulk Lycra ensures the socks retain their shape ride after ride and the 6″ padded cuff provides more protection to your leg and ankle.
Tell us some more about the technical aspects of the product?
Machine wash cold, tumble dry low
No bleach, softeners, or harsh detergents
66% Polyester, 32% Nylon, 2% Lycra
Really well made. No pilling or signs of wear after a month.
Kept me surprisingly warm, even dosed with water in high winds.
Still look good a month on.
Really comfy/snug, don’t slip down over the calf, even after three hours.
About right – I’m a 45 and the Large tested was nice and snug, rated from 43-45.5.
They are light for what they achieve.
No bunching and supportive where they need to be.
£27.50 isn’t cheap for a sock, but it’s the same as Sealskinz’ Super Thin Mid Socks, roughly the same as Showers Pass’ Lightweight Waterproof socks, and less than many others in the Sealskinz range (mid-£30s to over £40). They work and durability looks good.
How easy is the product to care for? How did it respond to being washed?
Fine. No issues in a normal 40 degree wash.
Tell us how the product performed overall when used for its designed purpose
Surprisingly well for a non-merino product. Especially with loads of water and wind involved.
Tell us what you particularly liked about the product
Warm shins. Can’t get enough of warm shins for keeping the feet warm. And dry-feeling feet after a soaking ride.
Tell us what you particularly disliked about the product
Nothing, really.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
A little more expensive than some: Dexshell Ultra Thin Modal socks are £22, Showers Pass’ Lightweight waterproof socks are £27. Cheaper than a range of Sealskinz options.
Did you enjoy using the product? Yes
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
Use this box to explain your overall score
If they were £5 cheaper and a bit warmer, I’d go for a 9.
About the tester
Age: 45 Height: 183cm Weight: 72kg
I usually ride: Merida Ride 5000 Disc My best bike is: Velocite Selene
I’ve been riding for: Over 20 years I ride: A few times a week I would class myself as: Expert
I regularly do the following types of riding: cyclo-cross, club rides, general fitness riding, mountain biking, Dutch bike pootling.





6 thoughts on “DeFeet Thermeator Knee High socks”
I think I’d go with leg
I think I’d go with leg-warmers, or knee-warmers or just about any other look than shorts and long socks. It’s certainly my knees that I want warm before my calves.
DaSy wrote:
I wear 3/4 Knicks a lot of the year, as my knees don’t overheat and I find full leg warmers are prone to either slipping over time or getting wet. Also I’ve worn these under a full tight for extra lower-leg insulation, where wearing a set of leg warmers would be a bit silly. Horses/courses.
KiwiMike wrote:
to stop this happening I’ve taken to wearing the ex-wife’s [1] suspenders over my bibs
[1] i still don’t understand why she left me…
DaSy wrote:
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DaSy wrote:
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If you have to wear these
If you have to wear these then you’re either inappropriately dressed (i.e. wearing shorts) or you longs or 3/4 lengths aren’t sufficiently warm for the conditions.
I wear half calf hiking socks when it gets cold but they are usually scrunched up just above my ankles with a pair of 3/4 or pulled up to lower calf inside full length bottoms.
£27.50 would get me around 2 pairs of very good quality Merino hiking socks, something I can use for off the bike, also you compare to the Sealskinz, did you actually check out how waterproof these are?
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