Direct drive. I do not have a tachometer. My understanding of the 3600 rpm generators is that they must be turning 3600 rpm to acheive 60 Htz from a two pole generator head. I have borrowed a photo/laser tachometer and had a reading that varied between 3270 to 3420. This is no longer available to me but I have been using my volt/ohm meter with a htz gauge. I verified the htz with an electronic gauge from "Hardy Diesel".