Racing for kids

So my 5 year old wants to race with me in the Aero
Army Wyn TT series. Because they’re so short

He’s on a single speed. What cat should I put him in??

Depending on what his FTP is you should maybe start him in D Cat.

Take his ftp divided by his waight in kg that will give you w/kg.

I am also running a race for juniors only. Here is the info Tour4Kids 2021 Announced. The races are longer though.