Like this site? Help us to make it better.


DeFeet Thermeator Knee High socks



A hardwearing, warm choice for cold-wet days out on the bike, on or off-road

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

What the scores mean

Good scores are more common than bad, because fortunately good products are more common than bad.

  • Exceptional
  • Excellent
  • Very Good
  • Good
  • Quite good
  • Average
  • Not so good
  • Poor
  • Bad
  • Appalling

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.

> Find your nearest dealer here

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.

DeFeet Thermeator Knee High socks - back.jpg

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.


A hardwearing, warm choice for cold-wet days out on the bike, on or off-road

If you're thinking of buying this product using a cashback deal why not use the Top Cashback page and get some top cashback while helping to support your favourite independent cycling website 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

Rate the product for quality of construction:

Really well made. No pilling or signs of wear after a month.

Rate the product for performance:

Kept me surprisingly warm, even dosed with water in high winds.

Rate the product for durability:

Still look good a month on.

Rate the product for fit:

Really comfy/snug, don't slip down over the calf, even after three hours.

Rate the product for sizing:

About right – I'm a 45 and the Large tested was nice and snug, rated from 43-45.5.

Rate the product for weight:

They are light for what they achieve.

Rate the product for comfort:

No bunching and supportive where they need to be.

Rate the product for value:

£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

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.

Overall rating: 8/10

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.

Latest Comments