Bias Ply tires vs. Radials – the automotive industry stopped using bias ply tires decades ago, but they’re still prevalent in trailer production. Why, you ask? Because unlike our cars and trucks, trailers do a whole bunch of sitting around. A radial tire may be superior for long-life on the highway, but when it sits stationary with weight on it, they are prone to flat-spotting. Bias ply tires have more “give” and are less likely to distort from long periods of sitting. If you trailer is going to sit and does most of its travel locally, bias ply tires are probably the right choice. If you are a seasonal resident looking to log several thousand miles per year traveling back and forth, a radial is probably a better choice for your application. here