The thermal image shows it: Who gets cold feet? We tested the following winter shoes for bikers:
- Heat 3D sole
- BBB BWS 04
- Gaerne Eskimo MTB
- Lake MXZ 302
- Northwave Celsius
- Pearl Izumi Barrier
- Shimano SH-WM 80
- Sidi Diabolo GTX
- Specialised Defroster
There's nothing like real leather," my father murmured quietly, taking a drag on his pipe and sinking his winter boots into a steaming pot of hot engine oil with an almost reverent motion. The same procedure every winter, a special kind of waterproofing every year. My father swore that nothing impregnates the good leather of shoes better than hot engine oil. That was in the early eighties and is completely out of date today. Today, leather shoes are treated with special leather greases. Or manufacturers sew highly functional outer skins made of Gore-Tex, nylon, polyurethane or other synthetic materials. But the goal remains the same: Winter shoes should be waterproof, warm, comfortable and supple. And to this day, there is no need to do without real leather. "Leather is extremely important for temperature regulation, especially in winter shoes," says Peter Thaler, head of the Lake brand. "Membranes make the shoe waterproof. But they are less breathable - damp feet cool down more quickly. Leather shoes, on the other hand, breathe much better." In this test, we try to find out whether this is true with seven winter shoe models.
We are also testing alternative ways to keep your feet warm in winter. On the one hand: Overshoes. These are usually made of neoprene, ideally have a robust coating and are very inexpensive to buy. On the other hand: Heated insoles. These high-tech insoles are now so small and flat that they fit into almost any shoe. Fitted with lithium-polymer batteries, they provide up to eight hours of warmth.
What really warms you up?
In the test, we rely on the expertise of TÜV Süd Product Service. We use a thermographic camera to determine the heat losses of the individual systems and models. The highlight: a thermal imaging camera can be used to display and analyse heat leaks. To do this, the shoe is first brought to foot temperature. The thermography then shows the heat loss in different colours. Green and yellow areas represent low heat loss, red or white areas indicate high heat loss. Overshoes, for example, lose heat primarily where the neoprene is in direct contact with the skin. This is particularly noticeable from the ankle upwards. A lot of heat is lost through the cleats on the underside of the neoprene sleeves.
Most winter shoes cool down at the same point. The reason is simple: the metal cleats are good heat conductors. As the cleats are directly connected to the inside of the shoe, a cold bridge is created; this is the case with Sidi, Shimano, Northwave and Specialised, for example. Whether the cold actually reaches the foot also depends on the construction of the shoe. Insulating inner soles, as with Lake and Pearl Izumi, or poorly conductive material in the toe area, as with Specialised, prevent cooling despite the cold bridge.
Another weak point of winter shoes is poorly insulating material around the upper. If the material used here is too thin (Shimano, Pearl Izumi, Sidi) or the shoe does not close tightly (Gaerne), heat is lost. Neoprene is particularly noticeable. Its elasticity guarantees a high degree of freedom of movement (Shimano, Specialised). However, neoprene is much thinner than the rest of the shoe. Heat is also lost here.
The construction of the shoe also plays a major role. It is important that the cold wind is blocked. An overlapping construction of the upper shoe helps, as any cracks through which heat can escape should be avoided. Northwave and Lake fulfil this task particularly well. Models with zips, on the other hand, have disadvantages as there is a draught through the unsealed zips. Conventional Velcro fasteners have a much harder time (Sidi, Shimano).
Shoe wet ? Call it a day!
However, moisture is much more dangerous than a wind hole. Just like metal, wet fabrics are ideal heat conductors. If a winter shoe gets wet, it loses all thermal insulation in a very short time. That is why we have subjected all systems to a wetness test. A specially constructed test rig simulates two and a half hours of continuous rain, mud, puddles and snow. The upper of the shoes is sealed in such a way that no water can run into the shoe from above. We also use this simulation to test the waterproof membranes used. The results are sobering: only a few shoes can withstand a ride through continuous rain for longer than two hours (Lake, Specialised, Northwave). All the others have major problems keeping the wet out. In all cases, however, this is not due to the membrane used, but to flaws in the construction. Water or creeping moisture have an easy time of it if, for example, the Gore-Tex membrane stops just above the instep (Shimano) or
water can penetrate through unsealed zips (Gaerne). If a heavily insulated, soft shoe also becomes saturated with water, all comfort is lost (Pearl Izumi). On the other hand, a neoprene overshoe still offers optimum moisture protection. It keeps all moisture away from the foot. However, this also requires a waterproof zip at the heel. The natural leather really came into its own in the practical test: On tours lasting more than two hours and temperatures around freezing point, all shoes with a waterproof membrane and especially the neoprene overshoe become damp on the inside. The warming function of the material decreases rapidly until your feet freeze. Only the leather MXZ 302 from Lake can withstand this and keep you warm even after hours.
Practical test
The BIKE test team took the shoes out on a defined test lap at around zero degrees Celsius and in the rain. The insights gained here regarding fit, comfort, power transmission, thermal sensation and handling are decisive for the BIKE judgement.
Irrigation test
During the sprinkling test, a specially developed test stand simulates a two-and-a-half-hour tour in continuous rain. As almost all winter shoes have a waterproof membrane, we test the moisture protection of the shoes under uniform conditions. In addition to a well-made membrane, the most important factor is the skilful construction of the upper shoe to prevent water from penetrating.
Thermography
In collaboration with TÜV Süd Product Service GmbH, we have carried out thermography on all winter shoes, the heating sole and the overshoe. With the help of this surface temperature measurement, heat leaks can be detected quickly and precisely. From the images of the sole and upper shoe as well as the practical test
we then determine the score for heat retention.
Simply click on the corresponding image to enlarge it. The pictures are sorted alphabetically according to the order in the test. The exact model is shown in the enlarged image below.
