For most people, typing text on a mobile device requires visual commitment to the input mechanism. As a consequence, there are many situations in our daily life when we have to refrain from using these devices as our vision is already committed. An example is trying to text while walking in a crowded place. Chording devices allow us to type without looking at the input device but using them requires some training. We present the results of a study that evaluates the performance of a key-to-character mapping for a 5-key chording device. The mapping is designed to minimize the learning phase. After 45 minutes of training it was completely learned, and after approximately 250 minutes the average entry speed was 15.2 words per minute. A prototype that implements this mapping was mounted on a bike and tested by the authors who could comfortably ride and type while being focused on the road.