I don't think there is much to worry about as far as wear and tear. Skinnier tires will probably improve low speed and parking handling because they have a smaller contact patch with the pavement. I've read that bias-ply tires actually put more stress and strain on the steering and suspension components than radials, if so, then the components that were originally engineered for bias-ply would probably breathe a sigh of relief with radials. Story time - when I was working for the Border Patrol in west Texas, (early 1990's), we got a bunch of shiny new Ford Broncos for patrol vehicles that were delivered with radial tires. Border Patrol operations go through tires rather quickly. Someone got the bright idea that we could save money by buying a truck load of bias-ply tires to replace the radials when it came time. Bias-plies at the time being notably less expensive than radials. That idea drastically shortened the service life of those Broncos. Where usually a cruiser could go a normal 4 or 5 years of service with no major issues, just about every one of those Broncos had to have the steering rebuilt at least once, suspension components replaced, and they all developed body cracks. Only lasted 2 or 3 years. Moral of the story being that those Broncos were engineered for radials, running bias-ply tires destroyed them.