Mons Royale Tarn Merino Shift Wind Jersey review – the only jersey you'll need for most of the year

Merino master Mons Royale’s windproof jersey works well in all but the nastiest winter conditions and doubles up as an excellent mid-layer for when the weather is really bad

Closeup of rider wearing jersey with bike in background
(Image: © Neal Hunt)

Bike Perfect Verdict

Combining Merino's naturally brilliant thermoregulation with a durable ripstop front panel has made this a go-to jersey for me in all but the hottest or wettest conditions.


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    Windproof front panel increases versatility

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    Loose fit feels very comfortable

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    Merino blend has great wicking properties and stays smell-free

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    Manages to be warm but not too hot or cold in all but extremes of temperature

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    Perfect for morning and evening rides where temperature changes mid-ride


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    High price point, but deals to be had

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    Sizing might be too baggy for some

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The Kiwi brand Mons Royale has been making ethically and ecologically sound Merino-based products for a while now, using pure and blended natural wool products to make some of the best mountain bike jerseys around, and the latest Tarn looks to take that a step further by adding a windproof front panel and a new blended material.

Close up of mountain biking jersey

The jersey has just one large logo on the left arm (Image credit: Neal Hunt)

Design and specification

To give it its full title, the Tarn Merino Shift Wind Jersey is Mons Royale's answer to the demands of big days out in the mountains, combining a relaxed cut with technical features no doubt inspired by the brand's long-standing experience in snow and mountain sports. There is a lack of big mountains close to me, but changeable conditions and plenty of steep, challenging climbs and descents of the Peak District and the surrounding area still put technical clothing to the test.

The jersey uses Mons Royale's new Merino Shift fabric, a blend of Merino and recycled polyester, reinforced by additional nylon fibers to boost the natural material's already stellar moisture-wicking and durability qualities. This is combined with a windproof front panel made from a ripstop material to keep chills at bay but without letting you overheat.

Close up of top part of a mountain biking jersey

The raglan sleeves are designed to aid with flexibility and to prevent any bunching up (Image credit: Neal Hunt)

The cut and fit is on the relaxed end of the spectrum. Despite its high-end fabrics, it is not a race cut and would suit a more comprehensive range of body shapes than some of the closer-fitting garments out there. It features a raglan sleeve, and Mons says the angled sleeve shoulder joint aids mobility and prevents bunching up when riding. There's also a neat little sunglasses wipe tucked away inside the bottom section of the jersey.

Close up of glasses wipe on mountain bike jersey

There is a neat glasses wipe at the bottom of the ripstop windproof panel (Image credit: Neal Hunt)

It is pretty subdued style-wise, with only one large logo on the left sleeve, and a combo of a deep bright red combined with black sleeves and a slightly charcoal color front panel. It also paired nicely with the Mons Royale Virage Pants I had on test. A black kit may be boring to some, and the old-school color combo may not be to everyone's taste, but I liked it. I also found it continued to look the same as when I first received it, despite many rides in all conditions and trips to the washing machine, unlike lighter kits that can stain easily after a few muddy rides.

All of Mons Royale's clothing is made to a high standard using ethically and, where possible, locally sourced materials. As a result, the jersey isn't cheap at $139.95 / £100 / €109.95, but it's on offer at lots of places online currently at $97.96 / £60 / €76.97 and considering it negates the need for a gilet, it's almost two tops in one and so could be seen as a bit of a bargain.

Mons Royale Tarn Merino Shift Wind Jersey on wooden floor

The colors and quality stayed looking bright and fresh despite plenty of wet rides and machine-washing (Image credit: Neal Hunt)


The relaxed fit worked for me; I found it really comfortable with no bunching or tight spots around the shoulders or chest when riding on various bikes in different riding positions. I had a size Large. I'd say sizing was on the larger side compared to the likes of Endura or Troy Lee Designs, with the chest measurement being very close to the stated sizing, and the torso cut left plenty of room, perfect for those of us without a six-pack.

The front panel hung slightly when I leaned forward over the bars, which initially felt a little odd, but I soon got used to it, and the raglan sleeves didn't awkwardly bunch and felt great with or without a backpack. The sleeves themselves are generous. I have longish arms and sometimes struggle, but there are no such issues here. Most of my rides involve a steep climb followed by fast descents, and this change in effort rate and temperature can be hard to dress correctly for, especially at the start and end of the day. I nearly always have a gilet on unless it's baking hot, but the Tarn negated this and was far more comfortable in practice.

Merino's ability to wick sweat is well known, and the Shift material, with its recycled polyester and nylon blend, seems to have made it even better. It has a luxuriously soft feel, even after a summer and autumn of high usage, and its ability to regulate temperature is quite something. It always just feels about right in anything but extreme heat or the dankest, darkest winter rides, but even then, it makes a great mid-layer to go under a waterproof.

The combination of the Merino blend fabric's thermoregulation properties with the ripstop windproof panel makes this the ideal partner for a big day in the mountains; or, like most of my rides, a power hour first thing before the kids are up, or a golden hour blast to catch the last of the sun where a quickly changing temperature can make or break a ride.

Rider on bike with landscape behind

It was nice to see some decent length sleeves when in the riding position (Image credit: Neal Hunt)


A comfortable, well-made, relaxed fit jersey made with a fantastic technical wool blend and combined with a windproof panel. It's a great jersey for all but the most extremes of weather, and it was ideal for the often changeable climate here in the north of the UK.

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Tech specs: Mons Royale Tarn Merino Shift Wind Jersey

  • Price: $139.95 / £100 / €109.95
  • Colors: Black, Dark Copper, Lichen Black, Retro Red Black, Walnut Black
  • Material weight: 140gsm
  • Material: Merino Shift
  • Blend: 35% Recycled Polyester, 52% Merino Wool, 13% Nylon
  • Sizes: Standard fit, S, M, L, XL, XXL
Neal Hunt
Freelance Writer

Neal has been riding bikes of all persuasions for over 20 years and has had a go at racing most of them to a pretty average level across the board. From town center criteriums to the Megavalanche and pretty much everything in between. Neal has worked in the bicycle industry his entire working life, from starting out as a Saturday lad at the local bike shop to working for global brands in a variety of roles; he has built an in-depth knowledge and love of all things tech. Based in Sheffield, UK, he can be found riding the incredible local trails on a wide variety of bikes whenever he can