Idaten Jump

Sho Wamato and his 5th grade friends, Takumi and Makoto really enjoyed mountain biking (MTB) when they practiced at the practice field, also known as the "X-Zone". Takumi was a skilled mechanic, while Makoto was a competitive female rider. Then one day, Sho was challenged by an MTB team named "Shark Tooth", and when the day came, black smoke appeared and they were sent to another world known as the "X-Zone". To return to their original world, they must compete in the "Idaten Battles", which involve races in numerous different setting, including volcanoes, ghost towns, deserts, and even at a cemetery. To win and collect 10 emblems in order to return will be tough, and will involve a loing journey. Will they ever make it back

Synopsis from Anime News Network