Well, I measured it and it looks like 1 3/8". My friend has a body shop and was fixing a wrecked gn. One axle tube was bent so he gave me the rearend and sway bar. I just took for granted it was factory. I guess if I road raced my car it would probably have oversteer issues.these days I just like to cruise around with a mandatory burn out everytime I get it out. With dropped spindles,oversize front bar,jounce,gp braces,and fender braces,it actually handles quite well. It handles highway cloverleafs very nicely. I am no expert but I would have to agree that my rear bar is overkill.