We make all or own chains for our grader's it is way cheaper by far to do, as far as using chains it depends on the conditions, if its just snow and no ice than I put chains on just the rear tires for extra traction but do not spin your tires with chains on, if its ice or a combination of snow with ice underneath 4 chains always with 1 on the front to help with steering, I have not ad any problems with wheel bearings or breaking the drive chain doing it this way, but reading what Nige has said makes me wonder if this is what happened to one of our M series graders in our sister shops with a rear axel bearing gone on one of the tandems on the left side, the operator might have been running just one chain on that side last winter, Hmm.