I would like to share a some observations on pinch rollers for the WM-100/200/500 series. I have worked on a number of these and there is often audible WOW that is synchronized to a full pinch roller rotation. There appears to be 2 types of rollers. 1) Roller (possibly early style?) that has a closed hub on both ends and a 1.2 dia hole (https://www.ebay.com/itm/125756456667). 2) Roller with one open end that accepts the FixyourAudio rubber tire replacement. It is important to note that this hole is a little larger and then has a step down to 1.2mm in the centre of the hub. If you have 2) above, I would suggest you ensure the hub is not out of round before ordering the FYA rubber tires. See video here: If you look closely, the new rubber tires did not fix the WOW as you can see that the hubs are actually cycling on the axle. You could assume that since there is a much narrower contact area, they are more suspectable to 'ovaling'. In this case, you need to order the ebay option as I don't think there are open ended hub replacements.
