How to: Cycling Apparel - Hurrah for Mid-Layers

It's gotten cold, but you're still ready to ride? What is important when choosing the right winter jersey...

Classic winter weather forecast north of the foothills of the Alps: 50 percent chance of showers with a maximum air temperature of five degrees. Not go for a ride? No way. If the motivation is there, the only question is, what apparel is right for a bike ride. What is most important? Protection from the wind? A real issues this time of year. Protection from the cold? Longing for a spring training camp answers this one. Protection from the wet? On a case-by-case basis. The latter can be done with a rain jacket quickly and easily. But because changing on the go is not an option: Which jersey works both as a middle layer between jacket and base layer, as well as "solo" over underwear when it is not raining!? 

In cycling, good jerseys for the cold season(s) should be able to do just that: to bind the air heated by the body around the biker like a kind of insulation shield and isolate them from the cold air. At the same time, however, the garment must "know" when sufficient warm air is available inside the jersey - and then allow the excess heat and sweat moisture to escape to the outside. And block the cold wind. Depending on the mix of materials, type of processing, construction and whether padded or not, one or the other works better. This is precisely the art of producing a functional jersey for rides in wet-cold, only cold or only wet weather. 

Body mapping follows a simple principle: body parts facing the wind are made windproof.

High speed, wind, continuous high intensity: this constant on the one hand and the wind on the other hand are the crucial points for Road bike clothing.

Clothing Mid-layer Middle Layer Change

High intensity uphill, a short break at the top, then downhill: the changes present the clothing system with real challenges.

Insulating and ventilating - how does that work?

To make matters worse, the above-mentioned requirements of a good bike shirt - keeping required heat, releasing excess heat, blocking wind - are not a given. Rather, they represent an ongoing challenge: Under stress, the body produces heat continuously, constantly heating the jersey from the inside. At the same time, the cold ambient air continuously cools down the heated air cushion. And the jersey has the complex task of maintaining the right balance between heating up from the inside and cooling down from the outside. So far, so good. 

The real challenge for the jersey is when it sees its position in the layer system changed by putting on or taking off a jacket. In other words: If it was just an outer layer over a base layer shirt and now it becomes a mid-layer. Or vice versa. Then it is suddenly exposed to cold wind, which sweeps away the laboriously warmed air cushion faster than you can say "freezing point". Or it faces another barrier, the often moderately breathable rain jacket, in terms of heat and sweat removal.

Appetite for construction

To meet these very variable requirements, bike wear manufacturers use different designs of jerseys. Because although there isn't one perfect shirt for everything, there doesn't have to be: the sensation of cold on the one hand and the heat balance on the other varies greatly from cyclist to cyclist. And in addition to all individuality, the daily fitness level of each individual is also taken into account. What seems to be the perfect clothing combination today may be perceived differently tomorrow, despite the same weather conditions. On top of that, it differs slightly from cycling discipline to cycling discipline.

So how do I find the right jersey?

Basically, with winter jerseys, we cyclists can choose between unlined and lined mid-layer apparel. In both cases, air is "stored" within the layer of clothing and heated by the body. With the padded textiles there is more air, with the unpadded ones less. In technical jargon, this is referred to as insulation performance. 

As a rule of thumb, the higher the intensity, the less insulation I need. On a Road bike, for example, padded jerseys - worn solo or under a jacket as a mid-layer - only make sense when it is really, really cold. In the city, on the other hand, for short distances, when the body only reaches temperature shortly before the destination or when you can expect standstill times in stop-and-go situations, a mid-layer with the right padding can be quite useful. Long MTB descents after a sweaty ascent, require good ventilation uphill and windproofing downhill. Padding? Rather suboptimal.
In the field of padded gear, manufacturers rely on synthetic fibre fillings: Polartec Alpha, for example, is a filling fibre fleece that has very good insulation values in relation to the filling quantity, but at the same time only slightly impedes the removal of sweat moisture. The same can be said about certain, rather thin Primaloft linings. Basically, the thicker the layer of filling material, the better the heat retention capacity. But also the worse the water vapour transmission. In other words, if you are under increased physical strain over a longer period of time, you will end up stewing in your own juices in thickly lined clothes, which can be dangerous, because a sweaty body also cools down more. It is therefore a logical consequence that down fillings haven’t found a hold in cycling. The insulation performance of down is in a sense "too good". In addition, down virtually attracts moisture, but then clumps together - and the insulating effect stops.

Mid-layer jerseys without padding usually use a special material structure for heat retention in order to keep the desired air cushion close to the body.

Three approaches, one goal: climate comfort

Temperature perception layer principle MTB Road bike

Temperature perception is highly individual, especially when working out. In addition, some people have different backgrounds: MTB left, Road right.

It's all in the material mix - and in the processing

The basic fabric used in jerseys for the cool or even cold days, the yarn, is an obvious distinguishing feature: The range of basic materials used extends from relatively widespread "simple" synthetic fibre fabrics to synthetic fibres with a special structure (e.g. hollow chamber fibres) and natural materials such as wool. Or a mix of all three. And even if the starting materials differ in many ways, they always follow the goal of keeping the right amount of warm air in the finished material structure. For this purpose, different raw materials as well as various processing and machining techniques are used. It is woven and knitted, whereby knitwear can initially bind more air due to the stitch structure. For this purpose, fabrics can be "brushed", i.e. roughened, on the inside. The effect: more air can be bound and heated in the enlarged surface than in the fabric whose inside has not been "brushed". In addition, brushing ensures that the fabric quickly absorbs moisture, distributes it over a large area and is well dissipated to the outside. In comparison with knitwear: roughly the same! Without doubt, materiality is often a matter of taste. For example, because certain skin types do not get along with knitwear made of wool (or wool content). Not even as a mid-layer with an undershirt underneath. In this context, a small excursion into the world of base layer: If a garment is worn as the first layer directly on the body, the question of the material composition and the way in which it is processed into a fabric is of central importance in terms of moisture removal from the skin. But we tackle this in a separate blog post.

Body mapping - the map of the cyclist's body

Just as body isn’t the same, functional clothing also requires differentiation from body part to body part. This does not even refer to the outermost extremities, which should be given special attention in terms of protection against cold, but to various areas of the torso, arms and legs. The chest and stomach, for example, are more exposed to the wind than the back. The area under the arms is a natural source of heat - and at the same time an important area for regulating the climate within a jersey. In order to meet the very different local requirements within a garment, numerous manufacturers rely on so-called body mapping. They design garments in such a way that the wind-facing side is counteracted by thicker yarn, partial padding or windproof components to counteract the dreaded wind chill (the difference between measured and felt temperature caused by wind influence). In return, wind-protected areas on the back, under the armpits or on the back of the upper arms are left out and designed with a view to higher water vapour permeability. In this way, body mapping supports the natural temperature regulation of the body without having to accept losses in wind and/or cold protection. Front zippers, higher or lower collar solutions also play an important role here. After all, the climate in the jersey (or jacket) can be influenced in the long term by opening the zipper on the ascent.

Windproof Front Body Mapping

Body mapping follows a simple principle: body parts facing the wind are made windproof.

Body Mapping Ventilation Back

Areas facing away from the wind (and those that generate a lot of heat, e.g. under the arms) are used for ventilation.

Does the fit fit?

However, all the efforts, considerations and sophisticated constructions on the part of the clothing brands are of no avail if the jersey does not fit properly. Naturally, the manufacturers themselves make great efforts to adapt the cuts of the middle layer to the requirements of different cycling disciplines: A Road jersey sits completely different compared to the casual position of Mountain bike jersey for Enduro riders because of the strongly forward bent position. Above all, the cyclist themselves can influence the performance of a cold weather jersey. Because when it comes to choosing the right size, you can be right - or not. Remember: The middle layer is intended to bind air around the body to create a warming cushion of air near the body. This does not work at all with a jersey that sits far away, or is too big. It's not for nothing that people like to talk about airy clothes in summer... But that doesn't help us very much when it’s 5 degrees outside. Therefore the insulating layer must be close, otherwise the heating power of the human body is not sufficient to heat the air layer. For rough orientation: If the speed is relatively high and relatively constant (=Road or Gravel bike), then a tighter cut works better, because although there is a large wind influence, the body continuously emits a lot of heat and can keep the relatively small air cushion inside the jersey at a good temperature. If your speed varies greatly, for example in the constant alternation of long ascents and subsequent descents on an MTB, a somewhat airier climate is more pleasant uphill as long as you don't neglect wind protection for the downhill. 

Fit Mid-layer Cut Tight Fit Wide Jersey

The closer a (mid-layer) garment fits the body, the smaller the air cushion. If the intensity varies greatly, a slightly wider jersey may even be more comfortable.

Overriding principle for the middle layer (and in general)

Even if the feeling for temperature and therefore the right choice of clothes is highly individual, as already mentioned, there is still a general rule of thumb: Dress in such a way that you will freeze to death after only a few minutes when you are outside next to your bike. Then there is nothing to stand in the way of riding fun even in bad weather during the cold season. And another plus, you usually have the trails/roads all to yourself in winter. This is one of the great advantages in autumn and winter!