To achieve the most accurate results, we recommend you use “pressureless” balls with your machine. It is not recommended to mix brands or ball types. All balls must be identical to achieve the highest level of consistency. We recommend Spinfire Touch tennis balls which have been thoroughly tested with Spinfire ball machines. However, other brands may also work well. You may also use pressurised tennis balls which will perform consistently when they are new, but may become inconsistent once their pressure drops.
Also ensure that your battery is adequately charged before use and regularly clean your machine, especially the throwing wheels. Dirty throwing wheels will inhibit the ability of the wheels to grip the ball, therefore creating inconsistent speeds and spin levels. Build up on the wheels can also affect their balance and may even cause damage to the machine.
Factors such as wind can also reduce accuracy and consistency.