The first systems to control traction came out in the automobile industry in 1932 by Ferdinand Porsche. Over the many decades since then, the popularity of the traction control system/TCS has gradually increased in the automobile industry and in motorcycle racing.
Today, the TCS has also become common on production motorcycles. With the area of the tire that is on road being only about 10 square inches (the size of a playing card), even small changes in the traction can lead to loss of control of the motorcycle.
Interestingly, one of the major factors in gaining popularity in this segment is because of the popularity of motorcycle ABS. A question that is commonly asked at this point is, “how does a motorcycles’ ABS have anything to do with acceleration?” The answer is that the ABS sensors measure the wheel speed and this is the primary data that a TCS needs to operate.
A basic TCS does a few things – first, they detect the rotation of the front and back tires via sensors. Second, an electronic control unit/ECU processes the information. Finally, an action that reduces the power to the back tire to stop wheel-slip is employed.
There are three actions, which are briefly employed, to stop or prevent the wheel-slip from happening. As with most things, they all have advantages and disadvantages, as noted below:
1. Intentional misfire – the ECU can briefly cut the fuel supply to one or more cylinders. On the positive side, this very effectively and immediately drops the power. On the negative side, it is abrupt and can risk the back tire catching traction too quickly, which can cause a high-side crash.
2. Ignition retard – the ECU can retard the ignition. On the positive side, this immediately drops the power and it can be done gradually compared to the on-off effect of an intentional misfire.
The first negative, is that by taking longer to slow the tire, this could mean the rider loses traction and slides out of control in the interim. The second negative, is with too much ignition retarding, there will be a misfire with the above-noted potential problem.
3. Throttle adjustment – if a bike has a wide-by-wire throttle/electronic throttle, it can limit the amount of throttle. On the positive side, it does allow for fine adjustments. On the negative side, it takes longer to get a drop in torque than the above two options and in the interim, there could be a low-side crash.
The most basic TCS are reactive, but there are more advanced TCS that actually predict loss of traction and implement countermeasures to prevent it. In addition to the wheel speed sensors, more advanced TCS utilize data from: engine speed sensors, throttle position sensors, gear position sensor, accelerometers, and gyroscopes to measure the lean of a motorcycle.
Today, TCS for racing applications can actually be fine-tuned. There are also aftermarket units that can be retrofitted onto motorcycles.
A concern that many riders have is that they don’t want anything adjusting their bikes’ performance, and this is understandable. The good news is that these control systems are only triggered once a rider is beyond a bike’s capabilities by giving it too much throttle or when there is a sudden change in the riding surface. Let us know what you think of TCS on social media.