27.5-inch mountain bikes come in all shapes and sizes and are found throughout all the mountain bike disciplines. 27.5-inch mountain bikes have a shorter wheelbase and overall length than 29-inch mountain bikes and are smaller than most 29ers. Most smaller adult riders tend to ride 27.5” bikes due to being more relative to their size and are easier to control, however, mountain bike tire sizes are not height-specific and are more of a personal preference.