Originally Posted by I-Like-To-Bike
How do these "alu* rims" that are so easily damaged by a tire lever, avoid being damaged while various kinetic forces are inflicted on them when being used; such as carrying a rider at speed and traversing on anything other than pool table smooth asphalt or training rollers? Or is that considered improper use?
Material gets damaged when critical stress is exceeded locally. Stress is applied force per area of application. A rope may be capable of carrying lots of weight, but you can cut with a knife using little force. The knife is effective, because it can concentrate the force over little area. Unfortunately, a lever can be also effective delivering stress to a rim. If you cover the lever in plastic, the contact area of force application will spread out both with a rim and tube.