we recently got our 06 extremes into the bike shop...we have been selling these bikes very well for 3 years w/o many problems...for some reason the main pivot on the 06 version loosens up very quickly making the bike unusable...i am referring to the X6 versions which should perform like the X1 from the last several years...putting wrenches on both sides of the pivot bolt shows that the bolt is tight on both sides...has anyone else encountered this on the 06 bikes???