Tweaking guide

tweaking is a glitch in the ds games that let's you walk over any plane by minipulating the map loading system. when you walk out of a town a new map loads right where the other is left off.
that is why the game slightly freezes when you are on your bike and going into a town.

Maps in Diamond and Pearl are broken up into 32-step by 32-step squares that are visible at any one time, with nine of these squares loaded at any given time. When a player crosses over the game's various "load lines", located halfway across these 32×32 squares, the next area is loaded to memory, while the previous is unloaded. Through this, the overworld becomes a seamless area.

Using the bicycle in fourth gear, however, can cause the player to move too fast for the game to load the areas properly, especially if he or she changes direction while doing so to cross over the two load lines in the center of a square nearly simultaneously. Doing so triggers a race condition bug, causing varying effects such as a black area, a white area, or even, at times, a completely different section to load, or often simply freezing the game.

The distortion caused by tweaking can be solved easily by crossing a load line away from the distortion, as when the section is loaded again, it will be normal. It can also be solved by looking at a different menu screen, then returning to the overworld.

TL;DR when you are moving at full speed on the bike, change direction when you are on the edge of the border.

There are risks though. You may get stuck inside the mystery zone (placeholder) until you reset the game. NEVER save when you are in the mystery zone. If you do than you may get stuck in the mystery zone forever unless you use fly. The game like it said above might crash outright so be weary of it.

There are benifits though. with the glitch, you can get the event pokemon, darkrai and shaymin fairly easily. you cannot get arceus though...

be careful and use it at your own risk. here is a vid showing you how to do it