Thanks BP.

The confusion is that in the world of cycling 20" don't necessarily mean 20". When tire choices are as limited as this, to me that means I got an odd sized wheel. My lbs sold me a tire labeled 20"(bmx?) but it was too small for my wheel. Gotta say 451 somewhere on it.

I did find a tire that fits at another shop and a 20" tube that really doesn't, but I stretched and squeezed 'til I got it all together and am able to ride. Will make another attempt next week to find the right tube, presta or schrader. I prefer schrader. As my lbs doesn't seem to appreciate the finer points of all this, will search the net.