Anti-roll bar
（重定向自Swaybar）
,_anti-roll_bar_-_Flickr_-_exfordy1608.jpg)
![One way of estimating antiroll bar stiffness:
T=Vehicle track width (inches)
K=Fractional lever arm ration (movement at roll bar / movement at wheel)
d=Bar diameter (inches)
R=Effective arm length (inches)
L=Half length of bar (inches)
S=Length of lever arm (inches)
Q=Stiffness (lb*in per degree)
[3]](/uploads/202502/14/Antiroll_Bar.svg1608.png)
An anti-roll bar (anti-sway bar, sway bar, stabilizer bar) is a part of many automobile suspensions that helps reduce the body roll of a vehicle during fast cornering or over road irregularities. It connects opposite (left/right) wheels together through short lever arms linked by a torsion spring. A sway bar increases the suspension's roll stiffness—its resistance to roll in turns, independent of its spring rate in the vertical direction. The first stabilizer bar patent was awarded to Canadian inventor Stephen Coleman of Fredericton, New Brunswick on April 22, 1919.