Anybody that's got a brain on understand what I'm talking about,LOL Dude you completely missed the point!I have well over 10,000 miles and still going with no chain line issues without one just like my real bikes that have NO NEED for one!For everyone else when a chain line has a change in direction it wear's the rollers and pins prematurely,and when spring loaded tensioner's fail the chain binds in the case around the output sprocket which can cause much more damage and headache's and this is why real bike's don't use them,it sucks when this happen's and lock's up the rear wheel when doing 40 imagine at highway speed or more !Sorry TopJimmy but when you can't even form a sentence (anybody that's got a brain on understand what I'm talking about) I don't expect you to understand why engineer's do what they do!