Sorry…I’m really not that into bikes so these terms are new…
Is shaving like shaving off those rubber things that stick out? and what is it for? Does it have the same effect as a swimmer who shaves his legs to be faster in the water?
What does it mean to true a tire? What does it do?
Shaving a tire is to remove all the nubs on it, so its completely smooth. This is usualy done with trials tires so that it reduces the rolling resistance and makes it a bit more manueverable for street and flatland riding. Its not something that has to be done, just a personal preference thing.
Truing a wheel is making it perfectly straight, so that when it turns there is no wobble and its perfectly centered in the frame.