While I don't have a Silverado, I have often bumped up one tire size on 4wd trucks when upgrading from the factory tires. This generally equates to an inch in height, more or less, and sometimes up to an inch in width. There has seldom been ill effects, except to lose a bit of fuel economy. Another item, which is also fairly important, is tire construction. Going from a P-metric to a similar tire that is an inch taller will generally only add a couple of pounds of rotating mass to go along with the lower effective gearing due to the increased diameter. It's often not much of a hit in handling/power/braking/mpg loss. But when you combine a heavier LT construction with the larger size, the weight and diameter combination can result in a more noticeable difference in driving characteristics. Just something to bear in mind. Many factory equipment tires are built toward the lightweight end of the spectrum for better ride quality and MPG, plus they are cheaper.
