16" wheels

I had some aftermarket 15" wheels mounted on my 1955 R-112 truck when I purchased it. I recently acquired a set of 16" International wheels and noticed they have a bit of space around the hubs. Shouldn't the wheel mount directly flush to the hub for support? My wheels are now lug centered and not hub centered...is this normal?

I was able to do some research here and actually answer my own question. There were several makers of auto wheels that provided parts for International during the 40's and 50's. Kelsey-Hayes was the most popular, but some IHC trucks were fitted with Budd wheels. Technically, Budd is a brand name, but it is also generically used to describe dually wheels. At any rate, Budd wheels tend to fit the International trucks with a "looser" fit around the hub, while the Kelsey-Hayes wheels provided more of a true, snug fit around the hub.