Love it or hate it, the days of the analogue motorcycle are all but over. ABS, traction control, ride modes… they’re all so commonplace on modern motorbikes that they barely warrant a mention on any review you’ll read or watch.
But, even deeper down, in the depths of the motorcycle, there’s even more clever stuff going on to keep us rubber side down. Motorcycle Stability Control, known universally as MSC, has been around for over a decade now but, unlike the more descriptive traction control and anti-lock brakes, it’s one of those technologies which isn’t really easily understood – which is why we wanted to dive deeper and find out what it’s all about.
Like so many advances in motorcycling technology, it was the German giants Bosch who pioneered MSC, introducing it on the 2014 KTM 1190 Adventure. To work, it requires an inertial measurement unit, or IMU. It was much trumpeted technology reserved for high end models a decade ago, but today its tech that’s filtered its way down to machines as small as 125cc.
Early ABS and traction control systems typically used wheel sensors to detect spin and lock up, crudely cutting power to activate traction control, or releasing brake pressure in the case of brake lock. Many riders didn’t like them, because you could really feel the systems cutting in, with pulsing at the lever under hard braking and an obvious sensation of the spark being cut when the traction control kicked in. That’s not something felt with today’s latest systems, which take a holistic view to make more accurate and less intrusive interventions that take into account the wider conditions and rider preferences.
And that’s all because of the IMU and the MSC systems it facilitates.
The IMU is a small sensor which typically measures the motorcycle’s movement, such as lean angle, acceleration forces, deceleration forces and the pitch and yaw of the bike. Data from the IMU combines with information from a whole host of other sensors, including wheel speed, throttle position, brake pressure and engine speed.
The bike’s onboard computer (or electronic control unit) analyses this input hundreds of times per second to decide how best to maintain optimal traction and stability, based on the bike’s lean angle and other factors. Wheelie control, for example, uses this information to determine how much to reduce power and torque to control the bike’s lift, based around the level of intervention requested by the rider.
And whereas early rider aids like ABS and traction control were standalone technologies, MSC is much more a suite of electronic strategies integrating seamlessly to enhance safety and rider confidence. These usually allow riders to modify the parameters of the electronics, allowing them to reduce or increase the levels of the intervention as they please.
Traditional ABS, for example, worked fine when the bike was upright but was less effective when leaned over. By having an IMU and MSC, the bike is able to identify when the bike is leaned over (and by how much) to optimise brake pressure and allow the rider to brake into the corner – something which was particularly risky in the pre-MSC era.
But it’s not just the ABS that’s dealt with by MSC. Many systems will also distribute braking force between front and rear wheels automatically under hard braking, improving stability and optimising stopping distances and, by monitoring pitch and yaw, MSC can also reduce power or adjust braking to prevent unwanted wheelies during hard acceleration and rear-wheel lift during emergency braking. And, because the processing time is so fast, intervention from modern electronics is barely noticeable to the everyday rider.
These rider aids are becoming more and more sophisticated every year. Radar technology is also being incorporated, providing even more input for the management system to work with. Adaptive cruise control, hill hold, launch control and drag control, where the onboard computer keeps the back wheel under control under aggressive deceleration, are new parameters riders are able benefit from these days.
Where high end bikes have typically utilised six-axis IMUs, Bosch has recently brought in a simplified ‘3D’ IMU for smaller and less expensive bikes. This 3D version features a three-axis accelerometer and a three-axis gyroscope, to facilitate a more basic version of MSC which includes lean-sensitive ABS braking.
Bikes like KTM’s 125s and even Honda’s humble Monkey range feature IMU controlled lean sensitive braking – confirming that this technology, which was previously only for the biggest and most expensive motorcycles, truly has filtered down to everyday bikes.
Photos: Bosch
