Originally Posted by
CliffordK
Cargo, touring, groceries, etc, would all add maybe 20% or 30% to my weight... or 20% more potential force on that axle.
Cargo is significantly harder on a bike than it's weight indicates, so 20% more cargo, might be twice the impact loads on the wheels.
The rider typically uses his legs to absorb and isolate impacts, while cargo is typically relatively rigidly attached to bike, so it dramatically increases the effective impact forces.