Changes in tire size will affect the amount of "trail" in the front suspension even if you increase the tire size by the same amount front and rear. Trail is the the distance from the theoretical point at which a line drawn through the king pin hits the ground ahead of the point at which a vertical line dropped from the spindle hits the ground. This is usually on the order of a few inches. Larger tires will increase trail and make steering feel heavier but more stable. Increasing caster will do the same thing for the same reason. That said, the truck will have a greater tendency to follow ruts.

Also changing the offset of the wheels will affect steering. Chevrolet has traditionally used a positive offset of 25mm (1") give or take depending on year and model. This results in the center of the tire being at or very near the the point at which a line drawn through the king pin hits the ground. That produces acceptably light and stable steering with the load center under the king pin. Changing to a zero offset or negative offset wheel to accommodate wider wheel/tire combinations will make the steering less stable and heavier as the center point moves outboard from the point at which a line drawn from the king pin hits ground, particularly on rutted roads. There are no aftermarket wheels I know of with the proper positive offset. I'm looking for a set of factory wheels for my '98 Suburban to correct this very situation.

1951 3800 1-ton
"Earning its keep from the get-go"
In the DITY Gallery
1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.