The GR in the Shimano GR5 Shoes stands for gravity. You know, that unseen force that works on all objects in the Universe, but especially big full suspension mountain bikes? These shoes are made to get the most out of gravity's pull, with sticky rubber outsoles to grip your flat pedals as you careen down mountains. Their uppers are made from tough synthetic leather, great at shedding water and mud, and a breeze to clean and maintain.