[ODE] Restricting ODE to 2D

[Ed Jones]

Hi Folks,

Say I wanted to write a motorbike trials simulation, similar to this; 
http://www.dnainternet.fi/pelit/english/

It'd be good if I could use ODE, but effectively everything's just in 
2D, so i don't want the bike tipping over to the side or anything like that.

I'm guessing that I can't just get ODE to "ignore" the third dimension, 
but can I use some sort of arrangement of joints to restrict the 
movement to just one plane?

Cheers,
Ed.