What MightyMount do I use with the CoreBar or JetStream Bar? Dave Updated January 18, 2019 03:47 Follow The MightyMount 39H is what you will need to fit non-Universal accessories to your Core or JetStream bars. Related articles CrossBar Options CrossBar Weight Limits The CrossBars that Yakima recommended for my vehicle seem really long. Can I cut them down to length? What is SmartFill? My car came with a factory rack or Aero style bars, what mounts will work? Comments 0 comments Article is closed for comments.