Side Impact Beam (Door Beam)

It runs roughly horizontally between the door hinges and lock area. It works together with the B-pillar and sill. Most modern cars have one in every side door. Some cars use roof rails and cross members in addition to door beams to resist side impacts.

The beam transfers impact load into the door frame and body pillars rather than letting the door fold inwards.

Do not cut or drill a door beam when fitting speakers or accessories. Replacement doors should come with the correct beam fitted.