Pera tires for Mini 4WD cars. Tire diameter is 23.5mm. Manufacturing process: 1. Pierce the shaft hole with a 1.8mm drill. 2. Cut the rim to approximately 22mm. 3. Surface the wheel. 4. Adhere using instant glue. 5. Shave down to 23.5mm. 6. Chamfer the tire edges. 7. Finish using parts cleaner and a melamine sponge. Other: * Uses genuine Tamiya products. * All are individually made, so there may be slight variations. * Measured with an electronic caliper.