Aluminum does not have an endurance limit like steel. In other words, aluminum will eventually develop fatigue cracks after X number of stress cycles, regardless of how low the stresses are. Steel, on the other hand, behaves differently. Steel can endure virtually infinite stress cycles, as long as stresses are below its endurance limit.
But aluminum bicycle frame engineers know all this. So, they design frames to last a certain number of cycles at a certain stress. Increases in stress, which is what “tgarcia2” is worried about, obviously mean a reduction in the number of stress cycles to failure. However, there may not be an increase in stress as a result of running different tires. Moreover, the life of your frame is probably measured in millions of stress cycles, so slight changes in stress will not have a significant impact on the life of your frame.
And as our pretty aviation mechanic alluded to, frames do not fail catastrophically without warning. Chances are great that a small crack will develop long before ultimate failure. So, it’s always a good idea to inspect your bicycle frame periodically.
Jason
PS: Do you think “she” is really a “he” aviation mechanic???