Meet Cardi Ellison :3
 
She is a former motorbike stunt pony, turned professional racer :3
 
Her parents used to work as mechanics for a bunch of stunt racers, taking their daughter backstage to the shows to let her see the stunts in action. She became fascinated by this and she took inspiration with those ponies and wanted to be like them.  
She got her first motorbike 13 years ago, at the age of 17, and treated it as though it were her own child. She soon started to learn more and more, and soon became part of a stunt team, where she was very successful.
 
After many years on the team, she soon decided that she needed more thrills in her life, and so she took up racing instead of stunts. Cardi started out just street racing at night but as the years went by, she got better and better, and soon became a professional.  
Currently, she is one of the best racers Equestria has ever seen, being able to complete laps and races in record breaking times, and is seemingly unstoppable.
 
Despite this, she still remains a humble pony, who is willing to help out other rookie racers when she can, ad she enjoys interacting with fans of hers, and enjoys telling stories of her time as a stunt pony.