Touch knobs usually require visual attention when performing a targeting task. This can draw the user's visual focus to the device, which is not desirable if the visual attention is needed elsewhere. In this work, we investigated the use of haptic feedback for touch knobs when performing another primary task that saturates the attention. In an experiment, we compare three potential tactile feedback designs to a no-feedback variant for a circular targeting task, while performing an attention saturating primary task. Our findings indicate that two investigated designs, namely, \textit{gradual+hapticObject} and \textit{adaptive+hapticObject}, providing the user with both haptic feedback on the objects and continuous haptic feedback through the trajectory, can serve as a reliable and effective mechanism for increasing the speed and reducing the mental demand for the secondary task while reducing visual distraction for the primary task.