Audiosilente idler wheel versus Artisan Fidelity idler wheel for a Garraed 401

I'm glad someone else revived this thread.  Up the thread, I wrote to Mozart: "Machining down the diameter of the idler would reduce platter speed."  Xactaudio seemed to disagree with me.  I am always ready and willing to learn if I made an error in abstract reasoning, which is entirely possible. I still think, all other things being equal, that an idler wheel of smaller diameter compared to original would cause the platter to travel a shorter distance for every revolution of the idler wheel.  Hence, the platter speed would be reduced unless idler wheel rotational speed were to be increased accordingly with the reduction in its diameter.  Am I wrong?  If so, I still cannot see it.

Mozart, There’s got to be more to that story. Machining down the diameter of the idler would reduce platter speed. That could be compensated by increasing drive speed but would hardly suffice to improve dynamics.

That's certainly the goal.  What you observed implies that the motor can overcome any additional load that might be imposed by the higher mass idler wheel.  (I intentionally used the word "might".)

 I wasn’t thinking that the heavier idler wheel would actually affect average platter speed. I was thinking that a lighter idler wheel would make the response time more rapid. By which I refer to the response to stylus drag or bearing friction or other factors that might put a drag on the platter. Because the motor only has to motivate the platter. Maybe The weight of the idler wheel or its moment of inertia is analogous to the compliance of a belt in a belt drive turntable. A belt with low compliance would be like a very light idler wheel.

In theory, wouldn’t you want a low moment of inertia, so the motor doesn’t have to do work to move the idler, in addition to moving the platter ? If so, I would choose aluminum over steel. The idler should instantaneously transmit force to the platter. (I don’t own a Garrard but do own a Lenco.)