The Assos overshoe is a fantastic piece of kit for the winter months or if it is wet on the roads or trails. The overshoe really work in keeping the water and wind from reaching your toes. As the feet are classed as an extremity then they are one of the first things to get cold and make your ride quite miserable. Overshoes do however get used in racing to make riders more aero. These are made up of a lightweight pvc material and are tight on the shoe to allow for the air to pass more smoothly and evenly over the shoe thus enabling the rider to go faster.
When fitting your overshoes they must be snug over the cycling shoe but not too tight that you have a fight with them. If the overshoe is too loose then the excess material will get in the way and you are likely to damage the material of the shoe. The overshoe has a gap on the bottom of the shoe to allow for the rider to clip in and out of the pedals easily. If the overshoe gets in the way of this then this is a good gauge as to whether the overshoe is the right size or not.