Hot Z28 is right. The 50 or 60 means the percentage of the width of the tire. A 50 series has 50% of the tires width as the height, etc. I bought a regal GS for my kid. Real nice ride, but the rims are only 6” wide so it limits the size of the tire that will fit. Not sure if you can go as wide as a 245 60/16. It may not fit the rim and if it does, the high offset of the wheel may cause it to rub on the inside fender wells when making turns.