Installing the tall / narrow tire
There are a few myths floating around on this thread, so I thought it might be helpful to examine the characteristics, installation and maintenance of a tall/narrow tire.
1. Tire roll in is a result of sidewall height, rim width and air pressure. It has nothing to do with tire width on a radial tire. A 285/75 on 8" wheel will exhibit the same wear and deflection characteristics as a 255/85 on a 7" wheel. A radial tire by design behaves this way. The assumption that just because a tire is narrower it will understeer more, or exhibit greater roll is incorrect. Tire deflection is managed on a tall tire by maintaining proper air pressure and correct wheel width (typically 65-75% of the section width). An IFS vehicle will exhibit greater tire roll in due to the change in camber through the suspension cycle, but that wear will be exhibited on all tires.
2. As with any tire, pressure is critical to proper wear and handling. Over-inflation will result in crowning, and under-inflation will result in cupping and increased heat and deflection at speed.
3. The 255/85 is designed for a heavy vehicle, they are rated at load D and 3,000 per tire. That can support a 12,000 lb truck. So with proper installation (air pressure and rim width), a 255 is an excellent choice for a heavy vehicle. I have used the size for tens of thousands of miles off-highway. The Turtle Expedition used that tire for hundreds of thousands of miles off-highway on an 11,000+ lb. truck.
So in summary, a 285/75 and 255/85 will deflect the same at pressure and with proper rim width. Tire sidewall deflection and rolling is a characteristic of section height, not width. A wider tire will be a bit more forgiving during high speed handling on tarmac do to the shallower loading angle. That benefit is negligible however between a 255 and 285.
While the tall / narrow tire might not fit the mall crawler look, their performance, efficiency and fitment benefits are significant.
