My 51 3100 came with 6 lug 16" wheels. The ones on the back were both split rims.The fronts are one piece steel rims. My 68 international 3/4 ton also had split rims.Were these original equipment on chevy 3100s? Why do some have them and some not?Were split rims an older application that got replaced with more modern types?What is the story on these things. Are there downsides to their use today? Curious ----Jack