The second part of our look at the ABS/TC electronics revolution examines the way the technology works. As simply as possible…
what it does
Traction Control and ABS exist in different forms, and operate in different ways, but share the same goal of keeping the wheels under control when the tyres are struggling for grip – a measurable symptom of which is wheel speed disparity. When a rear tyre spins up, it is no longer gripping the road efficiently, and rotates faster than the front. There are a number of reasons why this might happen, but it is often associated with a compromised road surface: water, mud, gravel, ice and diesel are all very good at compromising surfaces, even without the involvement of braking forces. Management of this type of scenario is the province of TC.
A front or rear wheel lock up also results in different wheel speeds: ABS seeks to remedy this by evening out the braking forces involved. ABS is effectively traction control applied to the wheels by attenuating braking forces instead of power (as is the case with TC). Increasingly, ABS and TC functionality is integrated: they are capable of working together to restore harmony.
how it does it
Neither ABS nor TC are new concepts: Honda had TC on a production bike in 1992, and ABS dates back much further. What is new – and still evolving – is the way they are applied.’Basic’ TC involves the detection and analysis of wheelspeed divergence, and seeks to remedy this by cutting power to the rear wheel via engine and/or ignition management. More advanced TC does the job faster, and factors in the effects of any lean angle involved by means of on-board gyros. Older ABS systems ignored wheel speed comparisons: sensors monitored the rate of de-acceleration on each wheel and acted accordingly. One of the major characteristics of a lock up is that the rate of speed loss is far greater than would be the case in a safe emergency stop. When the sensors detect this pattern of de-acceleration, brake pressure is reduced. Modern ABS effectively feathers braking in extreme circumstances, thus making it manageable. It combines wheel speed and braking force data to control the stop. Full integration with TC will allow the application of ABS while cornering: and some predict that a few years down the line we wont be thinking of ABS and TC as separate entities, since the two concepts will have effectively merged.
In the first part of this inquiry, we looked at the arguments surrounding the option of an electronics package, and came to the conclusion that anyone buying a new machine requiring maximum flexibility (all year round riding, an ability to do high miles in a variety of conditions) would be foolish to ignore these developments. If BG were buying new for general, daily usage we would definitely opt for TC and ABS. The problem of rapid change new technology is that if you don’t choose carefully, you may find the system you go for rendered obsolete within a relatively short period of time. If it works, that may not matter so much, but if you are going to invest the kind of money required for a decent new bike with electronic assists, you might as well get as close to state of the art as you can.
So what’s on offer out there? If you want a supermoto, can you get one with switchable TC and ABS? What about a naked? Or maybe a middleweight utility bike? We’re on the case and the results will form pt 3 of the series, but if in the meantime you are doing some research yourself be warned. It just isn’t that straightforward. You can buy a new machine which combines TC and ABS. The same bike may be available without one or the other or both. You may be able to retrofit the machine after purchase with the manufacturer’s control system – or you may not. You may be able to fit an aftermarket control system to an existing bike. Most confusingly of all, a manufacturer’s range may offer TC and ABS on a range of bikes – but the electronic spec withing that range may vary.
To keep things simple, we’re listing new bikes which c/w ABS and TC, and where their spec varies within a range, we’ll highlight it. We’ll also discuss whether or not ABS takes more getting used to on some machines than others. Eyes on the prize. Coming soon.