best mountain bike 1.high quality 2.competitive price 3.timely delivery 4.up-to-date mountian ... bike Mountain and BMX bike :1. Bike size: 18", 20" 24" 26" 28:; Foldable and unfoldable2. Color: ... 12"x1.75, 14"x1.75, 16"x1.95, 18"x1.95, 20"x1.95; With small guardWheel, safety ... Chain wheel & crank: 12" 24Tx89, 14" 24Tx88, 16" 28Tx102, 18' 28Tx 102, 20"28Tx127 CP/ED9. Chain cover: Full chain ...