Entry, at least 24 speed, front and rear disc brakes will be better! The minimum speed of flywheel above 24 is 1 1 tooth, which is most used for leveling and has high speed. Disc brakes are more agile when going downhill and are less prone to accidents. It is what you need to configure Duke Merida 550 and Giant 770 according to your requirements. In addition, you can buy 1.55 m ~ 1.65 m according to your height. 1.65 m ~ 1.75 m buy 17 inch, 1.75 m ~ 1.85 m buy 19 inch, 1.85 m buy more than 2.