The CoEfficient Hoody from Black Diamond is a bit of a legend in the fleece world. It’s instantly recognizeable at crags all over the place, and several times I’ve been stopped and asked, “how do you like your CoEfficient?” It’s also been through several design iterations, and what I’ve been testing is the most recent version you’ll find at retail.

Black Diamond CoEfficient Hoody Features:

  • Polartec PowerDry fleece
  • Low profile, under-the-helmet hood
  • Single zip chest pocket
  • Lightweight stretch cuffs with integrated thumb loops
  • Primary fabric is bluesign approved
  • Slim fit (but don’t size up)
  • Weight: 367 g
  • MSRP: $129
Black Diamond CoEfficient Hoody Review

Logos all over the place

Lightweight, versatile layering option

Springtime is prime testing season here in Washington State. I’ve enjoyed the CoEfficient on everything from multipitch trad climbing in Leavenworth to wearing it under a drysuit on the river. A

The cut of the CoEfficient is quite distinctive, so let’s start with that. It is, in a word, refined. Black Diamond really leveraged their climbing-specific DNA to create a midlayer that disappears when you wear it. The cut is very long, easily long enough to cover my backsideĀ so that it stays locked down beneath a harness. This also makes it great for cyclists, by the way, since it doesn’t ride up very easily. The sleeves are also cut fairly long for the size, and they terminate in very comfortable thumb holes to help the CoEfficient slide smoothly beneath a shell or puffy. Up top we’ve got an under-helmet hood going on.

The fabric base is Polartec’s PowerDry gridded fleece at a weight of 180gsm. This is on the lighter side of Polartec’s weight options, and is a bit lighter than the Patagonia R1 and a bit heavier than the Arc’teryx Konseal Hoody. In any case, the gridded aspect of this fabric is important because the border of each little square is thin fabric that breathes easily. As a hardface fleece, it has a DWR treatment for water-resistance, but don’t count on it during a downpour. It’s a durable, stretchy fabric (with 13% elastane) that is also environmentally sound.

Black Diamond CoEfficient Hoody Review

Sleek lines and minimalist zipper pulls

A few features deserve a little more attention since they’re highly relevant to the CoEfficient’s performance. A really key one is the design of the thumbholes. The sleeves are long and fleece fabric like this can get a bit baggy over time as it wears out, so the thumbholes will help keep things in line and in place and out of your way. Instead of a ‘hole’, it’s actually a fairly long, thin slit with a very cushy cuff that won’t cut into the skin next to your thumb. They’re probably the most comfortable thumb holes that I’ve used in a midlayer.

Another particularly well-designed feature is the hood design. It’s a well-designed hood that fits beneath the helmet and comes up high on the chin. When the hood is down and the jacket is zipped up, the hood lays around your neck and creates a nice warm seal against drafts. The full-length zipper rides smoothly and is a great way to dump excess heat when things get aerobic. There’s also a small chest pocket which I hardly used at all.

Black Diamond CoEfficient Hoody Review

The thumb hole is particularly comfortable

In practice, the CoEfficient is a joy to use. It’s just so well-designed. When you’re climbing, you need a piece that allows your arms and shoulders to move freely while not allowing the hem to rise. The CoEfficient nails this trait, with excellent range-of-motion in all directions. In practice, it’s also highly versatile across temperature ranges. I get hot and sweat easily, so I pay pretty close attention to my layers. For guys like me, the CoEfficient is a great fit for summer alpine starts on moderate routes or high exertion in the wintertime. Your mileage will vary, but my favorite temperature for the CoEfficient is in the mid 40’s with moderate exertion or the 30’s with higher exertion.

I don’t have any big criticisms on the fit or performance of this garment, but I do have some comments on quality of construction. Even when the jacket was new, there were several loose threads across it. That’s been exacerbated with use, and now I have a whole nest of them down on a high wear area near the cuff. Loose threads aren’t the end of the world, but they do make me question the quality control here.

Black Diamond CoEfficient Hoody Review

One of the little nests of loose threads

For reference, I’m 5’11” and 185lbs. I tested a Large and it was just slightly big on me.

The Good

  • Really excellent tailoring and fit
  • Comfortable, functional thumb holes
  • Great hood design, comfortable around neck when down
  • Zipper slides easily and doesn’t bind
  • Long, trim fit is ideal for climbing with a harness
  • Polartec fabric is an excellent performer all-around

The Bad

  • Loose threads aplenty (not sure if that’s common, but mine hasĀ several)

The Bottom Line: BD CoEfficient Hoody

The Black Diamond CoEfficient hoody is one of those rare pieces that deserve classic status. It’s just so well-designed and executed that you don’t want to take it off. I’d like to see them working to eliminate things like loose threads, but overall this is a very strong performer.

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About Author

Kevin Glover is an outdoorsman living, climbing and biking in Spokane, WA. Originally from the Nevada high desert, he moved to the PNW for its mild winters and allergen-free summers. He has guided throughout the Cascades and Enchantments for Peak 7 Adventures.

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