Crank parameters-----------------------------------------------------> Brand: rapido Product Name: hollow integrated disc crank Crank: 170mm Material: Aluminum alloy Specification: BCD 104 Weight: a set of left and right cranks 690g Advantages: it is made of aluminum alloy, light in weight, fashionable in appearance, dazzling in shape, strong in axial strength and strong in compatibility   The central axis parameters.-----------------------------------------------------> Commodity name; Hollow center shaft (external BB) Rotating structure; Sealed peilin bearing Suitable for: Shimano haomeng Nichi, etc Weight: 109 G Specifications; 41*24*24 with washer and screw teeth It is suitable for mountain bike and road bicycle. The width of five way is 68-73mm. It is compatible with Shimano and FSA. Giant atx770 & nbsp; atx770-d & nbsp; XTC 750   单盘参数-----------------------------------------------------> Brand:RAPIDO Type: positive and negative teeth single disc (disc) Material :7075- T6 Aviation Aluminum Alloy Thickness: 4mm BCD:104MM Process: Full CNC processing process. Specification: 32t 34T 36t 38t 重量:50g/57g/67g/79g Tooth number selection-------------------------------------------------> The number of teeth is suitable for people (take 26 inch wheel group as an example) 32T&The common BCD 104 crank can be equipped with small teeth (except for Fuliye's 30 tooth structure), which is suitable for the places with steep slope, XC & nbsp; cross-country (without expansion disc) or AMFR DH heavy-duty vehicle. Or middle-aged and elderly riders don't pursue speed. 34T    Commonly used teeth number (Take the 26-inch wheel set as an example) Most riders are more than 20 cruisers, with two gears in the front and seven or eight in the back. I'll ask if you want to speed up a little bit. If I want to, I will push 36t, if not, I will recommend 34T. There are two reasons why it is not 32. 1. In order to leave some space for the high-speed riders, 2. The common teeth of the rear flying should be close to the middle as far as possible, so that the speed can be up and down~~ Xc  cross country, now many cars are flying behind 36T, so the ratio of teeth is less than 1:1. It is awesome for climbing, and it can also accelerate. Am & nbsp; can also choose 36T&It's suitable for the riders cruising about 30 yards on the flat road, or the XC & nbsp; players with better physical fitness, or those who want to cross-country with the expansion plate, but also want to be faster. I am the 36 T before and after myself 38T&They are more inclined to mountain horse players, cruising 32 + ~ ~ ~ & nbsp; or with the expansion plate, the players in the competition