Wheelie Man could use some support here.
Let's consider the simplified case of several bikes that have the same horizontal pivot (or virtual pivot) coordinate but different vertical coordinates. That is, the pivot point is the same distance forward of the axle but at different heights. We also assume that the chain line is the same in all cases.
Let's say that in the lowest pivot position there's at least some anti-squat and some pedal feedback. Raising the pivot will increase the amount of both. That will tend to inhibit pedal bob, up to a point. You can raise it too much and cause an extending bob.
The more the pivot is raised, the more bump compliance will be reduced under power. At the same time the more the pivot is raised, the more bump compliance will be increased when coasting. Particularly for sharp-edged bumps.
Here's another largely unrelated observation. Assuming the same chain tension effects, the farther ahead of the center of mass the instant center is, the less the rear will tend to bob from rider weight shift. This is because more of the weight shift will be borne by front compression instead of by a rotation of the main frame.
Let's consider the simplified case of several bikes that have the same horizontal pivot (or virtual pivot) coordinate but different vertical coordinates. That is, the pivot point is the same distance forward of the axle but at different heights. We also assume that the chain line is the same in all cases.
Let's say that in the lowest pivot position there's at least some anti-squat and some pedal feedback. Raising the pivot will increase the amount of both. That will tend to inhibit pedal bob, up to a point. You can raise it too much and cause an extending bob.
The more the pivot is raised, the more bump compliance will be reduced under power. At the same time the more the pivot is raised, the more bump compliance will be increased when coasting. Particularly for sharp-edged bumps.
Here's another largely unrelated observation. Assuming the same chain tension effects, the farther ahead of the center of mass the instant center is, the less the rear will tend to bob from rider weight shift. This is because more of the weight shift will be borne by front compression instead of by a rotation of the main frame.