A Class C is a box truck full of heavy stuff, with high center of gravity, slab sides, easily disturbed by passing big rigs and riding on cupped concrete highways damaged by big rigs and weather extremes. The rear leaf springs are stiff to accommodate varying weights. Tires are stiff and under high air pressure to carry the weight. Cupped roads give a jolting ride which can promote tire failure when tires have sidewall cracks. Tires should be replaced every 5-7 years regardless of tread depth/appearance for your safety and to protect items under the rig from flailing steel belts. Upgrades can help, frequent breaks from driving help save your nerves. Driving on secondary black top roads, more scenic than interstates, that are in good condition, give a better ride. If long distance touring is your major interest, investing in upgrades may be a good idea.