OK, speaking of leaky beach wheels and adding inner tubes...

Does the valve stem on a 12x12-8 inner tube exactly match the location of hole on a tubeless wheel? I have those POS EuroTrax and wonder if they used a metric (S.I.) measurement in locating the hole in the wheel. I'd hate to have to figure out where to drill a new hole for USA tubes.

And why should they leak to begin with? Couldn't you just clean and reseat the bead on the tire and wheel, maybe grease it up to help the seal?