Originally Posted by ridelugs
bars are butted externally on a mandrel, would be my argument, then bent to form. hydroforming is pretty new to the bike world, but bulged bars arnt, really. read all about mandrels and thier many uses:
http://en.wikipedia.org/wiki/Mandrel
3TTT used to make their cheap bars by hydroforming decades ago. Their expensive ones were drawn over a mandrel, their intermediate bars were sleeved.