Like this site? Help us to make it better.


Castelli Free 9 socks



Particularly lovely, very stylish cycling socks that are the final and essential detail in your cycling outfit.

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

Castelli's Free 9 socks are lightweight and comfortable. They're good for coping with warmer weather but we're still wearing them as summer fades.

The Free 9 socks use a Superlight Meryl Skinlife in their construction that is extremely soft next to the skin. Pulling these on to your feet in the morning before a ride is as close to luxurious as it gets with cycling socks. They're really thin too so they provide minimal bulk between your feet and shoes, creating a well ventilated and airy place for your feet on warmer days.

A mesh construction extending from just below the cuff to the top of the heel gives them an extra boost when it comes to dealing with warmer days. There's no chance of overheated feet with these socks, that's for sure. Even as the temperature dips, well beyond the 17°C min temperature Castelli quote with the literature accompanying the socks, they continue to provide a comfortable and well-ventilated place for your feet. So don't necessarily discount them just because summer is waning.

They look good too, though looks is of course purely a subjective matter. Feeling good about how you look on the bike might only be the reserve of the vain, it matters a great deal to some while others aren't at all fussed about appearance, but there's definitely something in the 'look good, feel good, ride fast' mantra that some people peddle. And having clean and smart socks if the final, easily overlooked detail. Available in several colours and a range of cuff heights (these are 9cm high) there's a sock for all tastes.

You might be thinking £14 is a lot of money for a pair of socks, and it is. You can pay more (Rapha) but the DeFeet socks are nearly half the price. These Castelli socks work well to justify the price, they're extremely comfortable, hard-wearing and, several months down the line, they're still white.


It's hard to get excited about socks but these are particularly lovely, and very stylish, cycling socks that are the final and essential detail in your cycling outfit. test report

Make and model: Castelli Free 9 Socks

Size tested: n/a

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Our Rosso Corsa sock was the basis for the Free 9 Sock, but we've added a new mesh construction to the cuff to make it a bit cooler for summer. The graphics look great with any Castelli product, but they were specifically de- signed to match the new Free Jersey and Free Kit Bib- short.

Tell us some more about the technical aspects of the product?

Superlight Meryl Skinlife antibacterial fibers dries quickly and breathes exceptionally well to keep your foot temperature regulated on the hottest summer rides.

Diaphanous web on top of foot

9cm ankle cuff

Rate the product for quality of construction:

Typical Castelli excellence.

Rate the product for performance:

Top of the class stuff here, especially when it's warm. They're particularly good for racing, or any really hard riding when you put a lot of pressure through your feet pushing hard on the pedals.

Rate the product for durability:

Despite their lightweight construction, they're hard-wearing - certainly no holes in the heels as yet - and survive dozens of washing machine cycles.

Rate the product for weight, if applicable:

The thin fabric makes them feel very light on the feet indeed.

Rate the product for comfort, if applicable:

Yep, brilliant. Pulling these socks on in the morning will put a smile on your face.

Rate the product for value:

Yes that price tag does look awfully high, but they justify it for me based on their fit, comfort and performance.

Tell us how the product performed overall when used for its designed purpose

Very well indeed.

Tell us what you particularly liked about the product

The comfort against the skin.

Tell us what you particularly disliked about the product

Nothing to dislike.

Did you enjoy using the product? Yes.

Would you consider buying the product? Yes.

Would you recommend the product to a friend? Yes.

Anything further to say about the product in conclusion?

Excellent socks, do yourself a favour and treat yourself to a pair.

Overall rating: 9/10

About the tester

Age: 31  Height: 180  Weight: 67

I usually ride:   My best bike is:

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, touring, mtb,


David worked on the tech team from 2012-2020. Previously he was editor of and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds, and you can now find him over on his own YouTube channel David Arthur - Just Ride Bikes

Latest Comments