Large eccentricity can significantly affect the precision, repeatability and stability of the tire dynamic balance testing machine. However, few methods have been studied to eliminate or reduce eccentricity, which is only calculated for subsequent solutions in current compensation systems. An improved rim is proposed for compensation based on the original mechanical structure and calculation principle. First, some T-shaped grooves are slotted on the rim along the radial or circumferential direction. Then, T-shaped bolts with specific weights are inserted into certain positions. The practical examination proves that the improved rim successfully compensates for the system′s unbalance.