Unable to use Ram Runner online

Hi. I have a Ram Runner that’s in the A class. I wanted to race online using it on the A class category but it wouldn’t show up so I made sure and it is an A class car. Can anyone tell me why I can’t use it in the A class races?

See this: http://forums.forza.net/turn10_postsm447595_Have-cars-like-the-Escalade--Hummer--Limo--etc--been-banned-from-racing-online---see-post--52.aspx#post_447595