I’m glad you’re interested in the bike, Adi!
In a 2-wheel vehicle, the compression and damping of each suspension can be configured in Java, the same as for a 3- or 4-wheel vehicle. For the demo, I made the suspensions very stiff since any compression would misalign the brake pads with the rotors and the axles with the hubs.
Drifting occurs at high speeds. I believe there are examples in the video.
For “Classic Motorcycle”, the tangent of the tilt angle is proportional to the lateral acceleration. That formula isn’t hardcoded into the library (yet) so you can customize it as you wish. And I’m open to PRs.
In the demo, the rider doesn’t move at all. Even when the handbars turn, the rider’s arms and hands remain frozen! You are right that the programmer can run any animation they wish—unfortunately I don’t have good skills for creating animations.
Bike class creates a vehicle with 2 rigid bodies: one for the engine and one for the steering. It expects the 3-D model to follow certain conventions, such as having Y-up/Z-forward orientation and a distinct subtree for each body. Each body has its own center of gravity, located at the origin of its subtree. I never calculate an overall center of gravity for the bike.
Bike wheels are interchangeable with the wheels of other vehicles, so their 3-D models have to follow the same conventions as other wheels.
It’s not easy to add models to More Advanced Vehicles. When I gain more experience, I may be able to write a “cookbook”. For now, I’m available to help with troubleshooting.