In researching for my upcoming suspension re-build I ventured in the garage today and measured the sway bars on my 1977 US Spec 308 GTB. I came up with the following: Front bar: 18mm Rear bar: 15mm The rear size threw me because I was expecting either 14mm or 16mm. I measured it several times so I am quite certain that it is right. Is 15 mm a correct sized OEM Ferrari bar? Maybe Ferrari UK can chime in here.