I have a 2008 Road King. The service manual states the limits on belt deflection as between 6/16" and 7/16". Since you have to rotate the axle to set belt tension it's really hard to keep it in limits. Applying 100 ft/lbs of torque to the axle nut makes it hard to hold it steady with a wrench on the other side, and one little slip messes it up.

I set it Saturday to 6/16", put 100 miles on the bike yesterday, and it has already slipped a little.

Does it really always have to stay within those limits? If not, at what point does it really need to be tightened again? How loose is too loose?

Bob