tweak restitution

src/bike/wheels.rs

@@ -14,8 +14,6 @@ pub fn spawn_tires(
     conf: &WheelConfig,
     meshterials: &mut Meshterial,
 ) {
-    //return;
-    // re-set the collision group
     let (membership, filter) = BIKE_WHEEL_COLLISION_GROUP;
     let wheels_collision_group = CollisionGroups::new(membership, filter);
     let wheel_y = conf.y;
@@ -112,6 +110,7 @@ pub fn spawn_tires(
                 friction,
                 CyberWheel,
                 ExternalForce::default(),
+                Restitution::new(0.2),
             ))
             .with_children(|wheel| {
                 wheel.spawn(tire_spundle).insert(pbr_bundle.clone()).insert(