BM550 is designed for heavy off-road and electric power-assisted mountain bikes. It is designed by Koozer in Mainland China and produced in Taiwan, China. It has very fine craftsmanship and higher strength, making it more suitable for AM/FR/E-bike. High-intensity cycling demand.

Important note:for the explanation of common abbreviations, please check the specifications you need before buying. If you are not sure how to choose, please consult our professional salespersons, and we will give you accurate suggestions. We are not responsible for the losses caused by your own purchase mistakes.

28H/32H/36H = the hub has 28 spoke holes/32 spoke holes/36 spoke holes, can fit your 28/32/36 holes rim.

QR = quick release version = front 5x100/rear 5x135mm = front 9x100/rear 10x135mm QR

TA = through axle version = THR = front 15x100/rear 12x142mm

mini THR = mini TA = rear 10x135mm THR or 12x135 THR

HG/XD/MS = the hub's cassette body is compatible with Shimano MTB 8-11 speed cassette and Sram PG series 8-12 speed cassette(HG) / Sram MTB XG series cassette 11&12 speed(XD) / Shimano MTB micro spline 12 speed cassette(MS).