Merino wool is the bee’s knees in my book. I do my best to wear it daily and on the bike, I’ve found that I love Merino wool socks. Castelli has their own version of Italian woolies and they are good.

Castelli Merino 9 Wool Socks Features:

  • Merino wool blend
  • Mid-length protection with 9cm cuff
  • Midweight thickness
  • MSRP: $16.99
Castelli Merino 9 Wool Socks Review

The Merino 9’s are comfy and cozy on cold rides.

Ba-a-a-a-a means comfort in Italian (I think)

When heading out on cold rides, nothing beats the cozy comfort of Merino wool socks. The softness of the natural fibers and inherent warmth is unsurpassed by anything 100% man-made. I’m not going to pretend that these are 100% wool because those would fall apart like an AMC Gremlin, but the key is in the blend. It’s the proper mixture of materials that maximizes the good qualities of Merino and makes for a durable, warm sock.

I’ve been wearing these on my fall road and mountain bike rides. On the mountain bike, I’ve found them to keep my feet warm in my Specialized Expert XC MTB shoes down into the upper-30’s without shoe covers. On the road side, I’ve worn them with my Bontrager Velocis road shoes into the upper-40’s without shoe covers. That added warmth really makes the ride and not wearing shoe covers is one less thing to have to deal with when getting kitted up.

Castelli Merino 9 Wool Socks Review

The aftermath — some seriously dusty wool socks.

Where the Castelli Merino 9 socks will find a great sweet spot is for cyclocross. Those attacking the barriers will love the warmth on the bike and when running uphill, through sand and over barriers.

Construction of the Merino 9’s includes varied thicknesses and weave to maximize warmth, protection, comfort and breathability. Seams go unnoticed and my sharp, pointy big toes have done nothing to damage them so far.

Castelli Merino 9 Wool Socks Review

Road or MTB, the Merino 9’s have added warmth on cold mornings.

I wish the cuff height were a little taller, to be honest. When wearing them with shoe covers, they don’t quite cover the upper cuff, which is a tad uncomfortable. On the bright side, they stay stink-free even after repeated use. I have gone several weeks without washing them (do I admit that?). And, speaking of washing, my family of 6 is not consistent at following care instructions. These made it in a normal load and came out just dandy.

The Good

  • Added warmth in cold temperatures
  • Soft and comfortable
  • Stay stink-free for repeated usage

The Bad

  • Cuff could be taller

The Bottom Line: Castelli Merino 9 Wool Socks

Merino Wool has been a wonder material for centuries and modern twists on the stuff are only getting better. The blend chosen for the Castelli Merino 9 wool socks is spot-on for comfort and warmth.

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About Author

A native of the Pacific Northwest, Jason quickly developed a love for the outdoors and a thing for mountains. That infatuation continues as he founded this site in 1999 -- sharing his love of road biking, mountain biking, trail running and skiing. That passion is channeled into every article or gear review he writes. Utah's Wasatch Mountains are his playground.

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