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Assos Equipe RS Winter Long Sleeve Mid Layer review

Paired with the right jacket and base layer there might not be anything warmer on the market

Assos Equipe RS Winter Long Sleeve Mid Layer Thermobooster
(Image: © Josh Ross)

Our Verdict

Whether it's paired with a lightweight outer layer or adding extra warmth to your deep winter cycling jacket, the Assos Equipe RS Winter Long Sleeve Mid Layer does exactly as advertised, in exemplary fashion, then packs away neatly when not needed.


  • - Low bulk makes it possible to layer more heavily
  • - Integrated face cover and hood
  • - Incredibly warm


  • - Zipper uses small teeth and isn't offset
  • - Very aggressive fit is hard to get right

Assos has gone with a strategy of more layers for more options so you can pick and choose the right pieces for every situation. Part of that strategy is adding a mid-layer option and that means an incredibly warm insulating layer is now available. 

Assos develops its own fabrics and offers options for seemingly every temperature range. In the past, that meant picking between hard-to-differentiate jackets designed for only slightly different temperature ranges. More recently there has been a change of philosophy. Instead of integrating everything into every jacket, there's now a multitude of layers available. Pick and choose between the available shells, jackets, base layers, and the Assos Equipe RS Winter Long Sleeve Mid Layer Thermobooster to assemble the right garment for you. More versatility with less duplication is the idea. 

Part of making this new strategy work is the availability of new layers and that's where a mid-layer comes in. Take a look at our list of the best base layers available to start, then add one of the best winter jackets or one of the best waterproof jackets. From there, keep reading to see if you think the Assos Equipe RS Winter Long Sleeve Mid Layer Thermobooster deserves a spot in your rotation. 

Writer wearing Assos Equipe RS Mid Layer, with hood up, facing the camera in front of an orange background

When it's really cold you can pull up the integrated hood and face covering (Image credit: Josh Ross)

Design and aesthetics 

Conceptually the Assos Equipe RS Winter Long Sleeve Mid Layer Thermobooster is what would happen if you pulled apart your favourite winter cycling jacket. Discard the shell and you'll have a layer of insulation that approximates what Assos is offering here. You could recombine it with a shell jacket or with another insulated jacket for even more warmth. Speaking more pragmatically, the mid-layer is the same Osmos material Assos uses in its Equipe RS S9 winter bib tight but assembled as a top. 

Just like a bib tight there's a dual nature to the Osmos material in the mid-layer. The inner face is a brushed construction that works to trap air and retain heat. It's also exceptionally soft if it's against your skin. The outer face is a highly compressive warp-knit design. It acts as a shell anytime it's exposed directly to the air and the compression helps with layering. 

The lower portion of the mid-layer uses only three pieces of the warmest available Osmos: the heavy. In another nod to ease of layering, the sleeve edges and bottom are all raw cut. Raw cut edges can be fragile though, so there are reinforcements in important areas such as next to the zipper.

A close up of the zipper on the Assos Equipe RS Mid Layer

Raw cut edges keep bulk to a minimum but there's reinforcement where it makes sense (Image credit: Josh Ross)

Instead of ending at the collar, the Assos Equipe RS Winter Long Sleeve Mid Layer Thermobooster has another trick. Topping off the design is an integrated hood and face mask. Making sure it fits comfortably under a helmet and balances warmth with breathability, Assos has used Osmos light. 

The facemask attaches at the rear and keeps the front unattached. There's lots of length so that the front tucks into the body of the mid-layer and stays put while riding. If you'd rather pull it off, however, it will sit comfortably behind your head. 

When it's pulled up, the cut is such that when you need the most warmth only your eyes will show through. If something between off and almost fully covered is what you need, the Osmos material has enough stretch for adjustability. Using the whole head covering as a neck warmer is comfortable, as is pulling the chin protection down while leaving the hood in place. 

At the front across the left-hand side of the torso, an inbuilt pocket is constructed by overlapping one piece of material over another. This is plenty big enough to store a host of belongings, but as a mid-layer, it's not the most accessible of pockets, so probably best reserved for your keys or bank cards. It also serves as a pouch into which the jacket can be folded. 

Writer wearing Assos Equipe RS Mid Layer, with hood up, facing away from the camera in front of an orange background

The rear-only attachment lets the integrated hood sit comfortably between the shoulder blades when not in use (Image credit: Josh Ross)

Ride experience 

There are some pieces of cycling gear that change everything for me, and this is one of them. 

I'm always cold in the winter and spending hours riding in the cold and rain was a miserable affair. There was no layering strategy that ever really solved it for me until the Assos Equipe RS Winter Long Sleeve Mid Layer Thermobooster.  

Assos states that the point is to make your whole winter lineup more versatile. You can wear a lighter outer and combine it with warmer layers depending on the weather. 

Where the Mid Layer Thermobooster shines, for me, is as a way to add even more warmth to the warmest jackets in your closet. If I'm heading out when it's raining and just above freezing for a full day of riding, that's when I grab this. Add in your warmest base layer also and you've got a level of warmth that's not otherwise available. 

The integrated hood is wind and water-resistant and works better than any added pieces. You could do something similar with a hat and neck warmer but the integration here means less hassle, less air leaking, and more warmth. I don't have to mess around with storing pieces if it warms up a little and when I'm using it, it's incredibly warm.

It's more than just being warm too. Warmth without breathability isn't useful. This Mid Layer from Assos allows sweat to escape and I've never felt 'boiled in a bag'. In certain situations, I have ended up with a sweaty base layer but there seems to be just enough wicking that my skin feels comfortable. 

When it comes to fit, that's the only place things get a little rocky. Typically, I need to size up for Assos winter base layers. They use very high compression and the bulk of the winter pieces means less stretch than summer pieces. I wear a medium for a base but stick to my summer sizing for jackets with a small. For the mid-layer, I have a small and it technically works but it's somewhat uncomfortable unless I'm riding. 

To make it easier to layer, the sleeves end sooner than you expect them to. That, combined with a very short front and high compression fabric makes it feel like it's too small. That is until you layer up and start riding. Sitting on your bike, riding hard, the fit issues disappear, and my normal size small feels perfect. You'll have to decide if you want a little more ease in your fit or if you are okay with exactly the right fit that's only comfortable while riding.

A close up of the self-storage pocket built into the Assos Equipe RS Mid Layer

The front pocket will hold the entire garment for easier storage (Image credit: Josh Ross)


Assos aims for versatility with the Assos Equipe RS Winter Long Sleeve Mid Layer Thermobooster. By separating a layer of insulation from a jacket, it allows you to combine it with other pieces in new ways, enabling you to increase the warmth of lighter jackets when you need to. 

The real magic in the Assos Equipe RS Winter Long Sleeve Mid Layer Thermobooster lies in its warmth, particularly when things get really cold, and other options start to disappear. Combine this piece with your warmest jacket and warmest base layer and you are ready to spend a day in miserable weather. 

Tech Specs: Assos Equipe RS Winter Long Sleeve Mid Layer Thermobooster

  • Colour: Black
  • Weight: 280g (size small)
  • Size availability: XS-XLG
  • Material: Main Body: Osmos Heavy Integrated Hood: Osmos Light
  • Price: $189/£145/AU$300
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