OK Dave, put the through axle bolt through all the spacers and clinch it up tight -- can the "extension in the center with the machined surface slides into the wheel hub......Loosely" move any
laterally at all or is it supported internally by the axle OD and compression bound to the inner bearing race and other inner bearing race OD sized spacers on either side to make a clamped-together very firm assembly?
Yes, it has some room left for it to rock on the bearing -- the motion of the bearing rock could be stopped by the decreasing the defined clearance space you refer to to keep the pulley from rocking as much.
But might that space be there to keep the ball bearing from getting damaged by pinching the balls and busting the race due to axle nut clamp up pressure if that surface were do drag during assembly?
Thinking about it simplistically, if the spacers and bearing races weren't allowed to 100% stack up correctly (say by that flange dragging) then a ball bearing could get destroyed by compression forces when you clinched the nut up tight.
Certainly the wheel would not be free rotating for long if a bearing was put under any sort of strong side load for any reason.
Me, I think the rear pulley is allowed BY DESIGN to rock on the ball bearing some, making a broad but pretty short arc out at the belt end of the rear pulley rock motion.
If Suzuki left room in the "extension in the center with the machined surface slides into the wheel hub......Loosely" to allow the bearing clearance rocking/pivot motion, well, they might possibly think they are preserving the pulley bearing's life from some sort of loading that they thought might be adverse to the life of the bearing?
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But in the end we are all saying the same thing, the rear pulley by design moves freely side to side in a short arc, and that arc tells the belt to track from one side to the other which is determined by whether it is accelerating or decelerating at the time.
Rubbing of the entire flat side surface of the toothed belt across a flat side of a pulley flange makes a really irritating squeak sound, yep it does. We all agree on that point, I think.
So,
Dave has arranged to decrease the range of his arc by stuffing some extra material inside the hub. He accepts that he is perhaps side loading his pulley bearing slightly by doing so but he has decreased the side to side arc and improved his tracking.
(tracking error being a thing which can aggravate the squeak condition)
Oldfeller and MM have added a loading ramp to the belt edge and added some deburring and a bit of infeed ramp to the small and large pulley. Because their belts can load and unload freely now and only rest on the flange on the thin wide fiber-filled section of the belt their noise has abated permanently.
(and the broad plastic teeth on the belt no longer rub the sides of anything to make that aggravating squeak sound)
Two different ways to skin the cat -- anybody got a third way to skin the kitty?