Friction: There are three forces that affect the rubber in climbing: The first force occurs when standing straight on the foot hold. This is the dominant force when climbing walls. The second force is the friction that occurs when you pull your foot towards you on steep walls. The third force occurs when you turn (smear) your foot on the foot hold. All of this happens at the same time.
It`s a challenge to make rubber that is soft enough, yet at the same time also hard enough, so that is does not yield and bend on similar foot holds with full body weight applied. Another challenge is to make the rubber sufficiently tough yet at the same time soft enough to provide friction when there is little weight on the foot.
We have solved this problem by having rubber with different properties on our shoes.
A unique feature of the shoes is that they have cushioning built into the shoe, so that small micro vibrations from the bike are softened and the shoes stay on the pedal during hard blows. The sole itself stems from climbing shoe technology developed in California, i.e. fully synthetic and able to withstand stretching, where other rubber has easy breaking under stretch (eraser effect). It is also not so hard that it does not enclose the pins on the pedals. The top of the shoe is made of a soft synthetic material that dries easily and does not absorb much water.