Designed for young riders with adult supervision, the QuadSport Z50 / Z90 series features easy-to-pilot models with an automatic transmission. They are also equipped with many safety features, including a screw-type throttle limiter that allows you, the parent, to adjust the maximum speed to suit your child’s riding style and progress. The Z50 is recommended by Suzuki for ages 6 and up and the Z90 for ages 12 and up. But there are certainly younger riders who will be able to use the Z90 on private land naturally.