Why was Burt Reynolds in a wheelchair?

No, but here is your explanation: Stallone WANTED to make this movie about Formula 1, and F1 laughed at him; so he transposed the narrative to IndyCar, but kept as much of F1 in it as he could. Til Schweiger was supposed to be Michael Schumacher. Burt Reynolds was playing Sir Frank Williams of the legendary Willians team. Sir Frank has long been confined to a wheelchair. I guess Stallone’s Joe Tanto (the word for a Samurai’s knife) was supposed to be The Incredible Hulk.