Speed data can often be misleading because carrying more speed in one portion of the track can often cause a drop in speed in another. Entering a speed too fast can result in a slower corner or exit speed, and a compromise must always be found. From speed data alone, it is almost impossible to deduce whether or not a rider is sacrificing too much speed in one area in order to gain an advantage in another. The time saved or lost is what’s important, and here sector times can be used to guide the rider.
While speed is a basic channel provided by all systems, and a channel to which many other channels are related, in isolation is does not provide much information for improvements. Part of the reason is that speed itself is not what is being optimized; lap times are what are important rather than speed, and more speed does not necessarily equate to a quicker lap time. Consider driving from New York to Indianapolis at 50 mph. If you drive straight there, you’ll get there quicker than someone driving at 75 mph but going by way of Detroit. Always remember that time is the variable to be minimized.
Perhaps the most important aspect of any software package is the ability to overlay data from two different laps, whether they are from the same session, a different session on the same day, or a session from a year previously. This is where the bulk of improvements can be found; data from one rider can be overlaid on data from another, showing where one rider is faster or slower than the other. And multiple laps from the same rider can be used to show whether a certain line choice is superior to another in one particular corner, or where on the track one bike setup is better than another.
Applying a filter to a data stream will remove noise and make a graph of the data easier to read and interpret. Most software packages provide a filter for each channel, and the user can select how much to filter, or smooth, each trace. The sample rate at which a particular channel is set can also be used to filter the data. For example, a channel that does not change quickly, such as speed, can be sampled at a slow rate that will naturally smooth out most noise. Other channels may need to be sampled at a higher rate and then filtered to avoid losing data.
A useful feature of GPS-based systems is that the inside and outside boundaries of the track can be added to the map. This allows the user to quickly see if the rider’s line choice is responsible for an abnormal speed or other channel trace, and use the data accordingly. In addition, the resolution of most systems is accurate enough that the rider’s line around the track can be depicted and compared to another rider’s. The inside and outside edges of the circuit are mapped by riding or driving around the track, following the respective edges and recording the data. The mapping software can then generate the map from a normal lap, a lap of the inside of the course, and a lap of the outside.