Tooji is Miki's older brother. He was first seen fixing tires, while answering Miki's questions about the probability of a city bike making a steep hill climb, winning a race against a road racer, or if it would be possible to ride to Akihabara on one. When he witnessed Onoda trying to actually race Imaizumi to the climb, Miki stopped and raised the saddle on Onoda's bike, and Tooji was shocked to see how the boy gained so much speed once Onoda finally took off. After the race, he and Miki took care of Onoda when he collapsed.
When Tadokoro first started out as a cyclist, he was not able to keep up with the other club members. He came to Tooji and Mr. Pierre with the intention of quitting because he was not good enough to continue, but Tooji encouraged Tadokoro to continue cycling, but convert into being a sprinter. With Tooji's help, Tadokoro was able to develop his own cycling style and become a pillar of team Sohoku. When Tadokoro won the spirit checkpoint over Naruko and Izumida, he dedicated the win to Kanzaki.
When Makishima first joined the cycling club, some of the older members made fun of his dancing style and tried to correct it. As a result, he practiced on his own and recorded his progress on the wall of the club room under a poster. While choosing riders to compete in the Minegayama Hill Climb Race, Tooji discovered the marks and recognized Makishima's handwriting. Despite the objections of other club members, he chose Makishima as the third competitor in the race, which Makishima won using his unique style. This information is revealed in Makishima's Spare Bike chapters.
Tooji first heard of Onoda when his sister, Miki asked him questions about climbing to the back entrance of the high school or riding a city bike to Akihabara and back. In the anime, while Tooji was in disbelief, he witnessed Onoda's speed when he drove his van for Miki and her friends to follow and watch Onoda's race against Imaizumi. He also helped Onoda when he collapsed at the end of the race. In Ride 5, Tooji was on his way home when Onoda had a flat tire. It was then that Tooji properly introduced himself as the former captain of Sohoku's cycling team, and said that even the climbers of the third year riders could never get to the rear entrance hill in one go when they first started.
Imaizumi is a childhood friend of Tooji and his sister Miki. In the anime, Tooji introduced a young Imaizumi to the world of competitive cycling when he let him borrow a road bike from his shop to try out. Imaizumi ended up riding it for two hours and felt true enjoyment, something he lacked previously as he had no social life in school nor interests outside of schoolwork. Thanks to Tooji, Imaizumi started competing in races.