You never know when a rock will strike. Everyone needs to have a spare derailleur hanger in their riding kit. If you don't you risk getting stranded in the woods.
|Boost (12x148)||SB100, SB130, SB150, SB165, SB140, SB4.5, SB5, SB5+, SB5.5, SB6|
|Non-Boost (12x142)||SB5-carbon, SB6-carbon, 15' ASR-carbon, 15' ARC-carbon|
|Shimano 12mm Dropout Chip Kit||ASR-5 (alloy/carbon), ASR-C (2010), 575 (2011-2013), SB-66 Alloy, SB-95 Alloy, Big Top|