We're needing to replace all six tires on our '95 Fleetwood Bounder diesel. For safety's sake, should we stick to the tires recommended for our RV (over $200/ea. for both steering & traction tires), or is there another route we can go to save money without compromising safety? We do some over the road driving and some short trip driving. We don't go over any mountains at this point, but do have the opportunity to climb some hills in Pennsylvania.