Starting at 550 grams (30T) the FB557-1X is one of the lightest 1X Fatbike cranks on the market. It is designed for Fatbikes with a “Rear Dropout Spacing” (RDS) from 165 to 177 mm and combines all the technical innovations of the 2015 “XM557 platform”, with all the advantages of the B.O.R "Smart Drivetrain Concept" and the "Smart Spindle System".
The “FB557-1X” is the “FB557-Basic 170/177” as a “carrier” (490 g) combined with a mounted XX1 drive-train unit (from 60 g). This generated the complete, 30 mm spindle based “FB557-1X 170/177”.
With the XX1-compatible 76 mm BCD (like SRAM XX1) it provides easily replaceable 30T - 32T - 36T - 34T - 38T chainrings. They are lighter than other XX1-compatible rings and undergo a multi-stage, complex surface treatment that aims at high surface hardness and durability (Triple-Surface-Treatment).
Rear Dropout Spacing (RDS)
- Fully CNC machined (Light Alloy 7022/7010/7051), anodized with noble laser-Logo
- “Scotching” (additional surface brushing)
- Crank arm lenght: 175mm - 165mm, 170mm and 172.5mm at request
- Chainline: 65.5mm
- Q-Factor: 196mm
- U-Factor: 179mm
- K-Factor: 128mm
- Bolt Circle Diameter (BCD): 76 mm / 4-arm
- For 1x10-speed or 1x11-speed drive
Spindle length, chain line, K-factor and Q-factor of this crank was designed for Fatbikes 170/177 RDS (Rear Dropout Spacing) of 165 to 177 mm (narrow version). These usually have a rear dropout clearance of 165-177 mm.
Smart Drivetrain Concept
B.O.R. provide a versatile usability of the crank. Even regular with a spider or "Plug and Play"- power measurement on the spider. Thus B.O.R cranks are “Power Meter-ready” and enable the simplified retrofitting of measuring units from SRM and Power2Max!
Smart Spindle System
Developed in cooperation with Tune 2012, the “Smart Spindle System” serves as the basis for all B.O.R MTB cranks and secures for installing our cranks into 11 different bottom bracket types.
The specific bottom bracket shells are available separately.
Standard arm length 175mm - for 165mm, 170mm or 172.5mm please contact our service team.
A Shimano cassette tool (such as the Park Tool FR-5 Freewheel Remover) is required to mount the lock nut. The crank is supplied without a manual.