You could use it with a 2 speed, 3 speed, SUV (lol), anything where the wheels contact the ground. If you put the magnetic pickup on one gear of your two speed, it will only give accurate readings of that gear. If you put the sensor on a driveshaft or the wheel (if you can mount the sensor by a wheel, and the pickup on the wheel) it would work for a 2 speed. The directions explain this also.
Peace