When your Blue Ox Sway Pro spring bars wear out, bend, or get damaged on the road, this OEM-matched replacement kit puts you back in business without replacing the entire weight distribution head. The BXW4005 is rated for 550 lb tongue weight, making it the right choice for lighter travel trailers and smaller fifth-wheel setups where precise load leveling and sway control matter just as much as on heavier rigs.
The Blue Ox Sway Pro is one of the most recognized weight distribution hitch systems in the RV aftermarket, known for its friction-free sway control and straightforward round-bar design. The spring bars are the working heart of the system -- they transfer tongue weight back onto the tow vehicle's front axle and the trailer's axle, leveling the hitch and dramatically reducing trailer sway.
Over time, spring bars can develop stress cracks, surface corrosion, or slight bends from hard use, rough roads, or overloading. Rather than retiring an otherwise functional head assembly, the BXW4005 kit lets you swap in fresh bars and restore full factory-rated performance. At 18 lbs for the pair and 30 inches in length, these bars are a direct dimensional match for the 550 lb Sway Pro position in the Blue Ox lineup.
Designed specifically for the Blue Ox Sway Pro head assembly. No modifications or adapters needed for proper fit and engagement.
Engineered for trailers with up to 550 lb tongue weight. Matches the correct spring rate for load leveling in this weight class.
Blue Ox Sway Pro uses round spring bars that snap into the head with integrated retention -- no chains, no lift handles required.
Includes both spring bars as a matched pair so both sides wear at the same rate and maintain balanced load distribution.
The Blue Ox Sway Pro weight distribution hitch is a round-bar system that combines weight distribution and friction sway control in a single compact head. Unlike trunnion-bar systems that use L-shaped bars, the Sway Pro uses straight round bars that insert into the head casting at an angle and are retained by a snap-in locking mechanism -- no chains, no hooks, no separate lift brackets.
Blue Ox offers the Sway Pro in several tongue weight ratings. The BXW4005 spring bars are the 550 lb rated set, sitting at the lower end of the Sway Pro lineup and appropriate for smaller travel trailers. Heavier trailer owners should verify their system's head rating before ordering -- using 550 lb bars in a higher-rated head will underperform and could be unsafe.
Weight distribution spring bars take on cyclic stress every mile you tow. They flex upward under load and return to neutral when the hitch is disconnected. Over thousands of miles this can cause:
None of these conditions require you to replace the head, ball mount, or shank -- just the bars. The BXW4005 kit is a targeted, cost-effective fix that restores your system to its rated capacity.
Replacing Sway Pro spring bars is a straightforward job that most RV owners can complete in a driveway with basic hand tools. General steps include:
If your tow vehicle and trailer were properly set up with the original bars, the new bars of the same rating should restore the same level attitude without needing to re-adjust the head height on the ball mount.