The TRF Victorys are a team of Mini 4WD racers in the WGP competition, consisting of the main characters and representing Japan. TRF is an abbreviation for "Tsuchiya Racing Factory" (named for Dr. Tsuchiya), and it is also a reference to the real-life Tamiya Racing Factory, which also goes by the initials "TRF."

Retsu is one of the two title characters. He is a fifth-grade student who is 11 years old, and Go's older brother. Although he is able to control his patience better than his brother, he still lets out his annoyance with someone once in a while. Retsu sports a green hat as his trademark. His primary color is red, which is the color of his hair, eyes, gloves, shirt, and Mini 4WD cars. Together with Go, they are known as the "Let's Go Brothers" (レッツゴー兄弟 Rettsu Gō Kyoudai). In WGP, he is the captain of the TRF Victorys.

Go is the second of the two title characters. He is Retsu's younger brother by one year, and he is in the fourth grade. Go is rash, impulsive, careless, impatient, and brash. He is usually seen wearing goggles, but they are on his forehead most of the time as opposed to covering his eyes. His primary color is blue, which is the color of his hair, eyes, gloves, and boots, as well as his cars.