Dumb question on tire storage racks

[laplander]

Years ago I worked for a tire distributor and while they were tidying the place up they gave me a few two tiered tire dollies. I think there must have been room for 6 or 8 across each row, and the had wheels on the bottom so they could be moved easily. I'm back to the point of having multiple sets of wheels and tires and need a better way to store them. I've looked on ebay and the only things that I see that are close are stationary don't inspire the greatest confidence. Does anyone know the correct name for these things or where I could buy on or two?