You want the side car wheel (tire) to toe in and the bike to lean out (away from the sidecar).
I have read that most people use about 3/4" of toe in and about 3 degrees of lean out.
FYI, I have a 57" wheel base and about 10" of wheel lead.
When I set mine up, that's what I started with. It was a great starting point. I ended up having to lean mine out more so it would track straight - maybe about 5 degrees. I also later adjusted mine to a little less toe in, but believe I will have to go back to about 3/4" as I now get a bit of wobble (head shake) where I did not previously.
The drawback with "lean in" on the bike is that it will always want to turn right - you'll end up fighting it.
The drawback with "toe out" is very unstable and dangerous steering. The bike wants to crab down the road.
If you are truly referring to sidecar wheel lean in - mine doesn't ave any. Those that I have seen, have no lean in. Though I have seen motocross bikes on line that have a huge amount of sidecar wheel lean in.
DavePave screwed with this post 11-23-2012 at 06:00 PM