The RacksBrax HD Accessory Bars are the board-carrier layer of the RacksBrax HD quick-release system. They mount your full-size MAXTRAX and TRED recovery boards to the side of a roof rack instead of flat on top, so the whole roof platform stays open for a rooftop tent, basket, or fuel. Boards lock on and pull off in seconds — RacksBrax cites under 10 seconds once the system is installed — which is the difference between strapped-down weight and a board that's actually in your hand when you're stuck.
The bars carry the boards; the rest of the system does the locking. They clamp to a RacksBrax HD Hitch (sold separately), which is what gives you the fast unlock. On crossbar racks the two included T brackets transition the bars to the Hitch. On flat platform racks the bars can mount directly at the board securing-point separation with at least an HD Hitch in place. Either way, the swing-down clearance means once the boards are off, your rack height drops back down.
To run them you'll also want MAXTRAX or TRED securing pins (sold separately) — those are what physically pin each board to the bars. Compatible boards include MAXTRAX MKII and XTREME plus TRED Pro, TRED GT, TRED HD, ARB x TRED Pro, and the TRED 1100.
