Long-term review: Black Diamond Rhythm Tee with NuYarn, innovative nylon/merino blend

On a recent training hike in Boulder’s foothills, wearing the Black Diamond Rhythm Tee (and carrying an Osprey pack with two 12×12 concrete pavers, among other things).

At the end of a Black Diamond media lunch at Outdoor Retailer last November, I was given a t-shirt that we’d been quickly briefed about but that seemed like vastly inferior product seeding relative to the new powder skis and airbag packs that’d really wow’d us.

I’m notoriously particular about my athletic clothing, and I expected this Black Diamond Rhythm Tee would be dropped off at my local Goodwill before Christmas. Each year I receive mountains of new clothing, but I own only about a dozen go-to tops and bottoms — like an airy Smartwool long-sleeve from 2008, a wispy Salomon windshirt from 2013, and versatile Road Runner Sports short tights from 2014 — that fit and perform exactly how I want.

Long-term review: Black Diamond Rhythm Tee

To my surprise, the Black Diamond Rhythm Tee worked its way into my system. I’ve run in it over fifty times, including multiple long runs in the 2- to 2.5-hour range; and this spring I’ve been wearing it on training hikes with a 50-lb pack in the foothills in advance of a busy summer guiding schedule.

The Rhythm Tee is a simple pocket-less crew neck short-sleeve shirt. At $75 MSRP, it shares the uppermost price bracket with t-shirts from Smartwool, Arc’Teryx, and Salomon S/Lab.

Optimal uses

I’ve found it ideal for road and trail runs in cooler temperatures (upper-40’s through 60’s, at which point I switch to a singlet or go shirtless), and for hikes and backpacking trips in summertime conditions with low sun exposure (or with regular applications of sunscreen). The Rhythm Tee has general outdoor applicability (e.g. climbing and cycling), but I haven’t used it in other capacities.

Key specs

  • New for spring 2019
  • Pocket-less short-sleeve crew neck
  • 95 g/m2 fabric weight
  • Exactly 100 grams in size Medium
  • Made of NuYarn, 57% nylon and 43% merino
  • A men’s and women’s version
  • Available in Black and Nickel
  • $75 MSRP


The Rhythm Tee is most unique for its fabric, NuYarn, a product of The Merino Company.

NuYarn is made by wrapping merino fibers around a nylon core, and contains 57 percent nylon and 43 percent merino. I’d describe it as soft, airy, slightly textured, and lofty for its weight. After testing merino fibers between 17 and 19.1 microns, BD says it settled on 18.5 for the Rhythm Tee, because this fiber weight seemed to have the best balance of comfort and durability.

The Rhythm Tee is made of 95 g/m2 NuYarn, which is about one-third lighter than standard “lightweight” merino fabrics at 150 g/m2. It’s actually not much heavier than a pure synthetic — my size Medium weighs exactly 100 grams (3.5 oz), versus 90 grams (3.1 oz) for my favorite polyester running t-shirt made of Columbia’s Omni Freeze Zero (from 2017, if you’re wondering).

I’ve long thought that synthetic/merino blends could offer the best of both worlds, and NuYarn seems to validate this. The Rhythm Tee rivals the weight, moisture management, and durability of a pure synthetic knit top like Patagonia Capilene. But it also has the odor-resistance and temperature regulation of a pure merino shirt like the discontinued Ibex Hooded Indie, making it suitable for long trips and wetter climates. I’ve yet to find any downsides.

Illustration of NuYarn, courtesy of Black Diamond

NuYarn vs Core Spun Technology

NuYarn sounds similar to the “core spun technology” that’s now widely used by classic merino brands like Smartwool and Icebreaker. I’m unable to compare field performance; on paper, the two most notable differences are the fabric weight and the fiber ratio — core spun is heavier (150 g/m2 seems to be the lightest) and predominately merino (80+ percent). NuYarn should feel lighter and cooler, and it should dry faster, but it’s odor-resistance and temperature regulation may not be as wool-like.


The Rhythm Tee has an athletic silhouette that, thankfully, fits me perfectly. I appreciate the extra inch-ish in torso length, too, especially while wearing a pack.

For context, with most tops I prefer Slim Fit in size Medium; I can fit a Relaxed size Small, but the sleeves and length are usually too short.

If you have a more muscular or thicker build, do not be deterred. NuYarn is absurdly stretchy — about one-third stretchier than normal merino, per data from the supplier — so it’s more forgiving of different body types than more static fabrics.


My initial concern about the Rhythm Tee was its stretch. With extensive use, I feared it — and, by extension, its fit — would be lost, as happens with elasticized fabrics. But the Rhythm Tee fits the same now as when it was new, because the stretch is inherent to the fabric knit. I should note that I rarely wash it as recommended — after a run or hike, I usually bring my clothing into the shower, where I hand-agitate it in a bucket with mild water and detergent.

The sole durability issue I have found is abrasion-related pilling of the NuYarn. So far it’s superficial. In my case, the pilling is most notable on the chest and shoulders, underneath my pack straps.

In-house Martindale abrasion testing suggests that the 95 g/m2 NuYarn fabric is more durable than standard 150 g/m2 wool, which has endured many normal thru-hikes. I’m not yet sure that I’d recommend it for extensive bushwhacking though. Hearing from harder-wearing readers would be insightful.

Where the fabric has been abraded by pack straps, there is noticeable pilling. So far it seems only superficial.

Future products

Black Diamond will expand it use of NuYarn in its growing SolutionWool collection. In fall 2019 expect a 150 g/m2 baselayer long-sleeve crew shirt, tights, and three-quarter tights (as well as some mid-layers and an insulated parka). And in fall 2020 BD is considering a long-sleeve crew and long-sleeve hoody.

These final products have me more interested. A 95 g/m2 long-sleeve would be ideal for running in cooler weather. And a 95 g/m2 long-sleeve hoody would be perfect for backpacking in the sun-blessed Mountain West. I’d give BD bonus points if it treats the fabric with permethrin so that I can wear it in the High Sierra during peak mosquito season.


Black Diamond is often associated with innovative engineering, not necessarily sustainability. But it seems to understand that consumer expectations of climbing hardware are different than merino wool, so it’s doing more on this front with SolutionWool.

In particular, NuYarn will be made only from responsibly sourced, certified non-mulesed merino. And it’s working with Australian Merino Exports Pty Ltd to ensure that the wool is app-based traceable from farm to garment.

Questions about the Black Diamond Rhythm Tee, or have an experience with it? Leave a comment.

Buy now: Black Diamond Rhythm Tee

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Posted in , on April 24, 2019


  1. Bryan Treadway on April 25, 2019 at 5:38 am

    Excellent review as always Andrew

  2. Mike Grimm on April 25, 2019 at 8:43 am

    Thanks for the review Andrew! Really appreciate your insight/obsession with performance athletic apparel.

    Wondering your thoughts on Smartwool’s Merino Sport 150 fabric? I know it’s a heavier weight than the BD Rhythm (150 vs. 95), but seems like it has a similar mix of merino and synthetic. Biggest difference I can see is that it’s polyester instead of nylon blended with merino.


    Thanks for your thoughts!

    • Andrew Skurka on April 25, 2019 at 9:31 am

      I have not tried the “core spun” fabrics that now seem standard for athletic merino apparel, so I’m just speculating.

      The Sport 150 fabric is heavier (150 g/m2 vs 95 g/m2) and has more wool fiber (87 percent v 43 percent). So it should act more like traditional wool, but with marginally more durability and marginally better moisture management.

      What the specs do not reveal is the nature of the knit, which can really effect the air permeability, wicking, and stretch of the fabric. Product copy might touch on these qualities, but it will be so over-hyped that it will be impossible to really understand the differences without first-hand use.

      • Mike Grimm on April 25, 2019 at 9:40 am

        Thanks Andrew…wondering where you’re getting the 87% number from? The older “regular) 150 that Smartwool has used a higher percentage of wool, but the “Sport 150” is the following (based on online specs). I believe this “Sport” line is relatively new (late 2018 or Spring 2019?)

        Main Body: 56% merino wool/44% polyester
        Mesh Panels: 54% merino wool/46% polyester

        Anyway, thought you’d be interested and hopefully have a review sometime in the future.

        Thanks for all the great info you put out, I use almost all of it when making buying/planning decisions.

        • Andrew Skurka on April 25, 2019 at 10:25 am

          Sorry, I was looking at their basic Merino 150 Tee.

          Since the Sport fabric is similar in fiber ratio to the NuYarn, I think it will come down to the nature of the knit, in addition to the weight difference. The poly v nylon won’t make a big difference.

          • Mike Grimm on April 25, 2019 at 10:45 am

            Thanks for the info. Glad to see more brands doing the synthetic/wool blend.

            My interest was piqued by the Smartwool Sport line as they’re offered in a polo and quarter zip (although the vents don’t appear to be as deep as I’d prefer).

            Like you, I like to have a collar when backpacking and these check a number of boxes I’ve been looking for.

            Keep up the good work!

  3. matthew youngberg on April 25, 2019 at 10:21 am

    I agree with you on the hoody. My favorite Ibex hoodies are holing out so hopefully BD can do a longer lasting replacement

  4. Bob S. on April 25, 2019 at 11:42 am

    I don’t mind paying a premium price for quality clothing but the first thing I do is look at the label to see where the product is made. Are these shirts made in the USA or are they imported?

  5. langleybackcountry on April 25, 2019 at 1:46 pm

    As an FYI: There are a couple of companies that may be recognized by climbers and skiers – Trew and Ortovox – that are also using NuYarn.

  6. Javad on April 26, 2019 at 11:16 pm

    I’ve been wearing a Minus 33 Merino Wool t-shirt for long hikes and backpacks and I love it. Once I took it for running and ended up getting jogger’s nipple (I’m a guy). After doing some search online, I realized that it’s a very common symptom for wearing rough fabrics (https://en.wikipedia.org/wiki/Fissure_of_the_nipple). The problem went away as soon as I switched back to cheap $10 t-shirts.

    Q. Have you had any experience with jogger’s nipple? Do you think this puts me through the same pain as Minus 33?

    • Andrew Skurka on April 27, 2019 at 7:34 am

      Chafed nipples is very common. Think about it: in a mile there are about 1500 steps, plus/minus depending on your pace. Try rubbing a fabric over your nipple 1500 times in 8 minutes and let me know how it feels.

      The easy solution to nipple chafing is athletic tape, or Band-Aids. For the past few years, when I’ve been running 3k-4k miles per year (~10 miles per day), I basically had tape over my nipples 365 days per year.

      Every runner is a little bit different because of nipple size, chest hair, running gait, clothing, natural perspiration, and temperatures/humidity, but for me I need to tape up for any run longer than about 1.5 hours.

    • Tanner Buller on June 12, 2019 at 8:55 pm

      KUIU makes NuYarn base layers in a 125g/m2 weight for ultralight hunting. They push their gear to the limits before even putting them to market and they say they have experienced no problems with durability so far and very minimal pilling. (Regular washing in a conventional washer)

  7. Kupe on April 27, 2019 at 7:16 am

    Thanks for posting this, Andrew. I’ve been lamenting the recent deterioration of the Black Diamond core-spun merino wool “Deployment Tee” I got 5 years ago, and this looks like it could be a worthy replacement.

    I suppose the answer is obvious given how you have been using the Rhythm shirt, but do you find the shoulder seams to be irritating under pack straps? I’ve mostly been using the SD L/S Pack Polo and have prized its offset seams for strap comfort.You have me wondering if I’ve just bought into the marketing hype of such a feature and whether it’s really that much of a benefit.

    • Andrew Skurka on April 27, 2019 at 7:25 am

      I haven’t noticed the seams on the Rhythm Tee. In fact, I couldn’t tell you where they are on the shoulder. If they’re on the top, then offset seams don’t matter. If they’re not on the top, maybe they do, but I’d have to wear another shirt to find out. That all said, I have not worn it with a pack for longer than about 2.5 hours, and the 50-lb load distracts me from discomfort anywhere else.

      • Kupe on April 27, 2019 at 7:34 am

        Thanks! That’s great to know. Sounds like this is definitely worth checking out.

        I love the training with a backpack full of concrete, by the way. I may have to try that myself someday.

        • Andrew Skurka on April 27, 2019 at 7:35 am

          It’s not full of concrete, it just has two 12″ x 12″ pavers, wrapped in two old bath towels. Then there is some other stuff in there to fill it up some, and keep the main weight in the small of my back (not higher or lower).

          • Kupe on April 27, 2019 at 2:05 pm

            I appreciate the clarification! That sounds much less unwieldy than I imagined.

          • langleybackcountry on October 14, 2020 at 12:10 pm

            Lighter weight, but bags of charcoal distribute weight around the volume of a pack well for training. I also have an old climbing rope for pack-filler.

  8. Harry on September 22, 2019 at 4:49 pm


    Has BD discontinued it?


    If so, could you suggest another lightweight tee for for all-day hiking wear?

    • Andrew Skurka on September 23, 2019 at 9:53 am

      It’s a summer product, so they’re probably not bringing in additional stock until spring 2020. I don’t know for sure that it’s a spring 2020 product, but BD seems pretty excited about and committed to NuYarn, so I suspect they will.

      Are you looking for a shirt for the East? In that case, I would recommend a simple t-shirt. Patagnoia Capilene Lightweight is nice, but I’d probably look for something with some wool in it for odor-resistance. If you can’t find NuYarn from another supplier, then maybe look at Smartwool Merino Sport, https://www.smartwool.com/lightweight-merino-wool-base-layer.html

      • Harry on September 23, 2019 at 10:13 am

        Hi Andrew,

        Thanks for your reply. I am looking for something to wear if it gets cool at night during the Pinhoti 100 (Nov 2 near Birmingham, AL). I sweat a lot and will wear a singlet as much as possible, adding arm sleeves if it starts to get cool. But if the temperature is dropping at night I might want to change into something dry and short-sleeved.

        All the info that you share here is great! Thank you!

        • Luke Barnes on September 24, 2019 at 9:10 am

          KUIU ULTRA 125 base layers by Nuyarn are the best wool shirts in the world in my opinion. They keep me warm at night or even in the rain and I’ve never been too hot in them. They cool me off better than synthetic in temps over 100. Also, since KUIU is for hunters they’re made with a doubled up nylon core for durability and come with a lifetime warranty for all the seams (and zippers if they have them).

  9. Cameron Leslie on October 14, 2020 at 9:13 am

    Mr. Skurka,

    Your choice of ballast; why concrete pavers? Genuine question.

    In the past, I have used water bottles. If things ever were going bad, or if one ever finds themselves in over their head, one could empty the water bottles.

    I guess you could ditch the pavers, too. That seems like it might violate LNT.

    Regardless of answer; you’re still a badass. 🙂

    • Andrew Skurka on October 14, 2020 at 10:20 am

      They’re heavy/dense and were easily available to me (leftover from a landscaping project). I also knew that I could carry them and wouldn’t need to drop them somewhere.

  10. langleybackcountry on October 14, 2020 at 11:33 am

    I’ve been wearing one and have a couple observations:
    1: I love wearing the wool instead of the synthetics I’ve been using. The synthetics aren’t bad, but they can sometimes feel a little clammy.
    2: Questionable durability. I have worn it for maybe 15 days total and it got stained from a backpack (that have used for 2 years) and has a small hole in it near the neck. I will be contacting Black Diamond warranty.

  11. Kupe on November 7, 2021 at 8:13 am

    Hi Andrew. Did you ever try out the long-sleeved version for cooler runs, or do you still use your Salomon top?

    • Andrew Skurka on November 8, 2021 at 6:55 am

      The L/S is much less remarkable. Not as airy, seems like a pretty standard fabric.

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