BOR crank XM557 Boost 2X SmartSpindleSystem 2x LK 104 | 64 with chainrings
The XM557 crank the German manufacturer BOR based on the proven XC666. However, changes and advancements let the weight of the XM557 continue tumbling down. In detail, this means a weight-reduced Lockring that secures the optimized Spider. The crank arms have been calculated once again and could lose a few grams. The arms are mounted on an aluminum shaft with 30 mm diameter to meet even most powerful sprinter with best Steigikeit.
BOR typically comes also the proven Smart Spindle System is used, which makes it possible to build the crank in almost any context. Furthermore, even the Spider can replace. Here with Spider for Boost frame with optimized chain line.
The CNC machined chainrings BOR aluminum are as always hardened in a special process with a glass mount peening and then anodized with double the usual thickness. This Double Surface Treatment gives the leaves by a significantly increased shelf life!
The size chainring has various switching ramps and -gassen, providing a fast and reliable switching operation.
Made in Germany!
intended use: Cross Country, Marathon, Tour
Material: alumnium (7022, 7010, 7051)
Crank arm: 170 mm, 175 mm, 165 mm and 172.5 mm
Shaft: 30 mm diameter
Q: 164 mm
Chainring spider: 2-fold with LK 104 | 64 mm
chain line: 52.5 mm
Bottom bracket: BSA, BB89,5 / BB92, BB30, PF30, BBright MTB, BB386 EVO MTB (optional)
Chainring: 34 - 20, 36 - 22 and 38-24 or 40-26 teeth
Compatibility chain: 10x or 11x
Color crank arms: black
Color Spider / crank bolt: black, red
Weights without bottom bracket:
560g 34-20 teeth
570g 36-22 teeth
580g 38-24 teeth
590g 40-26 teeth
1x Boost Spider
1x large chainring
1x small chainring
Note: crank is designed specifically for frames with Boost standard (148mm).