32 pitch gears were the first thing used in our hobby, and just like 1/8th nitros today that use them it was the standard pitch for gearing on the first on-road RC cars back in the 1970s and early 80s. In the mid 1980s they developed 64 pitch gears, and like today they were primarily used by 1/12th onroad guys to give themselves more gearing options. A few years later in the late 80s marked the release of the first 48pitch gears, and these were the primary choice of offroad races as they were a happy medium, between 32pitch that didn't get fouled with dirt very easily and 64pitch gears that required a lot of upkeep, and still allowed for a greater number of gearing options than the original 32pitch gears.