A tire impact test method was developed to measure the natural frequency of vibration for lawn and garden rear tractor tires. Data from the tests illustrate how a tractor chassis outfitted with a particular set of tires responded after its rear tires were impacted from free-fall.The vertical impact response of four different tire sets are presented. Two commercially-available tire sets vibrated primarily about 4.4 Hz, and to a lesser degree about 72.5 Hz. Two experimental tire sets had a lesser fundamental natural frequency of vibration (3.4 and 3.6 Hz), and also vibrated to a lesser degree about 72.5 Hz.The fundamental natural frequency of the commercial tires fell into the zone where human tolerance to vertical vibration is minimal. The fundamental natural frequency of the two experimental tire sets remained below this zone.