Unfortunately the parts catalogs show no images or any other information about those rims (and I have multiple years worth). I do know that Weinmann had knurled versions of its rims, but so far it seems as if Schwinn would use them sometimes and then not. For example I've seen knurled versions of the Weinmann clincher rims on several original '71 Sports Tourers, however the catalogs list them as the same p/n as the non-knurled rims and there is no separate number or callout for knurled versions. After riding on them I can tell you they really howl and seem to really eat up the old pads!