BOR crank XM557 Boost 1X SmartSpindleSystem 1 times LK 76
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 30 mm in diameter to meet even the most powerful sprinters 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 chainrings have specific narrow-wide teeth that prevent the chain may come off.
In conjunction with a Sram or Shimano Shadow Type2 + derailleur, which have greatly increased bias of the cage, the chain is reliably held in place without chain guide.
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: 1-fold with LK 76 mm
chain line: 52.5 mm
Bottom bracket: BSA, BB89,5 / BB92, BB30, PF30, BBright MTB, BB386 EVO MTB (optional)
Chainring: 30, 32, 34, 36 or 38 teeth
Compatibility chain: 10x or 11x
Color crank arms: black
Color Spider / crank bolt: black, red
Weights without bottom bracket:
520g 30 teeth
525g 32 teeth
540g 36 teeth
553g 38 teeth
1x Boost Spider
without bottom bracket
Note: crank is designed specifically for frames with Boost standard (148mm).