Bike (Side-B):
Maximum Damage: 11%
First Attack Frame: Frame 20
Knockback: KO’s Mario at ~170% (at the center of FD with no DI)
The Bike is a great move with much versatility. It can be used to plow through many projectiles and attacks, but be careful using it when you have a lot of damage. If you're hit off stage without your Bike, your recovery ability drops significantly. Speaking of recovery, make sure you don't angle the bike forward since this seems to diminish the height of the jump you get from the bike.
Of course, the Bike can also be broken and the wheels can be thrown as projectiles. The Bike itself can be thrown as well, but much slower. I find that it's good to throw the whole bike up with the C-stick; this causes the bike to bounce a lot and forms a sort of defensive wall in the process. For the wheel projectile use, I like to glide toss or bounce them just like the Bike.
In regard to projectile defense, the Bike can block a lot of projectiles, but some of them require the wheelie (just press up to wheelie). Watch out for explosives and ROB's laser in particular when using the Bike.