A strut bar is designed to reduce this strut tower flex by tying two parallel strut towers together. This transmits the load of each strut tower during cornering via tension and compression of the strut bar which shares the load between both towers and reduces chassis flex.

A direct result of this is improved chassis rigidity (similar to that gained from a lower tie bar); hence, the understeer is reduced, tire wear improved and metal fatigue is greatly reduced in the strut tower area.