In Pokémon Platinum, you don't actually switch bike gears like in a traditional cycling game. Instead, you have two bike settings: the Acro Bike and the Mach Bike. To switch between these bikes, you need to visit a bike shop in Eterna City and choose the bike that suits your needs, with the Mach Bike allowing for faster movement and the Acro Bike enabling tricks and stunts. Gear changes refer to different bike functionalities but are not explicitly numbered like in some other games.
there is no acro bike on Pokemon platinum, you press B to change gears
press b
you can't it only goes up to gear two. To switch gears press the B button.
At Eterna city.Go to the bike store.Has 4 gears......
To switch gears on a bike, you use the gear shifters located on the handlebars. Pushing the shifter in one direction makes the gears harder to pedal, while pushing it in the other direction makes them easier. This allows you to adjust the resistance and speed of your bike.
Unfortunately, you can't change gears on bikes in HeartGold.
at enterna city
you don't..... you press B to switch gears
To change gears on the bike, all you have to do (while riding it) is press the B button. You don't have to hold it in, either. ~Lucario
You gain it in Eterna City after saving the owner of the Bike Shop in the Galactic Building.
When its going slower derh.....................
use your bike but press b when you are on.