The_Red
Guest
I ran a 6620 with the 915 head this fall.  It almost sounds like your terrain following feature is a bit heavy against the ground.  We only ran 500 acres of combined winter wheat in July and soybeans this fall.  I am guessing from the wear we will get one more season and have to replace them.  Probably like the plastic forks.  We are not getting much mileage out of them.