The Flame Runner.
|Unlocking||Available from start.|
The Flame Runner is a large vehicle, therefore it can only be used by heavy characters. It's a Bowser-themed bike, and one of the three best karts for time trials, although it's not very good for Grand Prix because of its poor acceleration. This bike is one of the three great time trial vehicles: Bullet Bike (small), Mach Bike (medium) and Flame Runner (large).
The Flame Runner is called the Bowser Bike in regions other than North America.