I was setting up the verlets differently - directly beneath the rigid body but I see how the above verlet / constraint combinations would make it far more stable provided I add more constraints than you suggest -e.g. connecting the wheel to a few more of the rigid body verlets.
I'm already doing what you suggest to get springs working. I may be back for more help
Thanks Luke .. will post back with results.
I'm already doing what you suggest to get springs working. I may be back for more help
Thanks Luke .. will post back with results.