I have a 2012 2DR Dozer, and I need a bike/ski rack for the hitch. Since I need 9.5" clearance from hitch bolt hole to outside edge of spare tire, for most racks I need an extension. The hitch has a 200lb tongue weight, and they are saying that if you extend, you have to cut the tongue weight in half. So what I want to know, is it safe to have 4 bikes on a hitch bike rack if you use an extender ? Total weight would probably be around 140lbs.