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.



 * Cars: Sonic Saber (ソニックセイバー Sonikku Seibā/;)/, Vanguard Sonic (バンガードソニック Bangādo Sonikku), Sonic 600 (ソニック 600,Sonikku rokuhyaku), Hurricane Sonic (ハリケーンソニック Harikēn Sonikku), and Buster Sonic (バスターソニック Basutā Sonikku), and Blitzer Sonic (ブリッツァーソニック Burittsā Sonikku) and the latest, Rodeo Sonic.

 * Birthday: April 10

 * Blood type: A

 * Height: 124 cm (roughly 4'1")

 * Weight: 28 kg (roughly 62 pounds)

 * Hobby: Collecting postcards

 * Hometown: Japan

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.



 * Cars: Magnum Saber (マグナムセイバー Magunamu Seibā/;)/, Victory Magnum (ビクトリーマグナム Bikutorī Magunamu), Magnum 600 (マグナム 600 Magunamu rokuhyaku), Cyclone Magnum (サイクロンマグナム Saikuron Magunamu), Beat Magnum (ビートマグナム Bīto Magunamu), Lightning Magnum (ライトニングマグナム Raitoningu Magunamu)and the latest,Bison Magnum.

 * Birthday: August 1

 * Blood type: O

 * Height: 120 cm (roughly 3'11")

 * Weight: 25 kg (roughly 55 pounds)

 * Hobby: Manga, video games

 * Hometown: Japan

Ryo is a wanderer who, with his brother Jiromaru, lives off the land. When he first meets the Seiba Brothers, He quickly becomes their rival, particularly that of Go. Eventually however, he becomes a friend of the Seibas and as well as a member of the TRF Victorys.



 * Cars: Tridagger X (トライダガーX Toraidagā X), Neo-Tridagger ZMC (ネオトライダガーZMC Neo Toraidagā ZMC), Rising Trigger (ライジングトリガー Raijingu Torigā/;)/

 * Birthday: August 27

 * Blood type: O

 * Height: 140 cm (roughly 4'7")

 * Weight: 37 kg (roughly 82 pounds)

 * Hobby: Fishing

 * Hometown: Japan

Tokichi is a spoiled rich boy, because his father is the owner of Mikuni Corporation. When he first meets the Seiba Brothers, Go takes an instant liking to him, most likely because of his money. His family owns an arcade (which instantly attracts Go), which is always the hot spot for kids. When speaking, he pronounces "desu" (です, meaning "is" or "to be") as "degesu" (でげす/;)/. His strength is making cars with emphasis on their technical cornering ability. Tokichi also likes to make his entrances in overly extravagant manners stereotypical of rich people, such as jumping out of a helicopter, arriving in a limousine, and surrounded with an entourage with great fanfare.



 * Cars: Spin Axe (スピンアックス Supin Akkusu), Spin Cobra (スピンコブラ Supin Kobura), Spin Viper (スピンバイパー Supin Baipā/;)/

 * Birthday: March 3

 * Blood type: B

 * Height: 118 cm (roughly 3'10")

 * Weight: 28 kg (roughly 62 pounds)

 * Hobby: Japanese tea ceremony

 * Hometown: Japan

Initially a battle racer in the Ōgami Corps, trained under Dr. Ōgami, he later finds enjoyment in regular racing with the Seiba brothers. Because of this, he decides to leave Ōgami Labs, renouncing the anything-to-win attitude instilled by Dr. Ōgami, and goes to live with Dr. Tsuchiya in his laboratory as an assistant. As a result, he also gradually changes in his personality, turning from an introvert into a more cheerful boy. Of all the other team members, J is the most skilled technician/mechanic, having prior experience with computers and machines while under Ogami's training. These skills are proven on many occasions, namely when he repaired the damaged Tridagger X to repay Ryo for damaging it in a previous race, when he helped Go design and build the Cyclone Magnum and when he designed the Proto Saber EVO. He appears to be best friends with Go.



 * Cars: Proto Saber JB (プロトセイバーJB Puroto Seibā JB), Proto Saber Evolution (プロトセイバーエヴォリューション Puroto Seibā Evoryūshon)

 * Birthday: December 14

 * Blood type: AB

 * Height: 140 cm (roughly 4'7")

 * Weight: 32 kg (roughly 71 pounds)

 * Hobby: Gardening

 * Hometown: Japan