I am getting ready to change the gearing on my 03 450F from 14/49 to 14/47. I currently have Ironman sprockets which have absolutely no signs of wear on either the rear or countershaft sprockets. Would any of you with Ironman sprockets change both or just the rear sprocket? Normally, they say you should do chains/sprockets at the same time but these sprockets have outlived a few chains already so I am not sure. Thanks for any help.