SWEMS - Suspension Wheel/Energy Management System
Suspension Wheel/Wing Energy Management System (SWEMS) restraints are attached at multiple points to a car’s chassis and suspension to minimize the possibility of wheel assemblies becoming detached during high-speed accidents.
The rear wing also has one or two restraints attached from the mainplane to a secure location on the transmission. With their high-tensile Zylon material and wound construction, each restraint has a break load of 100 kilonewtons (kN), which equals 22,480 pound-force. INDYCAR introduced SWEMS in 1999.
“We have several on each wheel and two on each wing, so a single failure does not mean it is detrimental to the retention system,” INDYCAR director of engineering Jeff Horton said.
Visual inspection of the restraints is part of the initial safety inspection on event weekends.
If any of the four corners sustain an impact, the rulebook mandates changing the SWEMS on the affected corner.