Aesthetics, also sometimes the trail can be too large (like with choppers) making the turning radius a little ridiculous. The shorter the forks and stiffer the springs however, the rougher and less stable the handling is going to be. Also this is not to be confused with "raking" a bike out, aka adjusting the angle of the rake. This can be dangerous because it manipulates the front frame where it meets the front-end but can also adjust the angle of the forks in a literal sense. Hope that answered your question. Google bike wheel "trail" to understand what I'm referring to fire handling control. Cheers
Lowbrow (parts and guys) are trustable, these tip vids are valuable but are more of a look into what the mod takes, Ya still gotta check out the official instructions included with parts.
