“If you’re leaning the bike and apply too much brake, you could be overloading the tires, because it doesn’t know how far you’re leaning,” van Hooydonk says.
Using wheel-speed sensors, conventional ABS systems sense when one wheel is about to stop spinning, or lock, because the brakes were applied too suddenly. The wheel sensors send that information to the engine control unit (ECU), which controls the anti-lock brakes, and limits the brakes by pulsing them to slow the wheels more gradually. As a result, the rider more easily maintains steering control, and his/her stability improves when the motorcycle is upright.
Cornering ABS applies the brakes at a level that’s safe for the motorcycle’s lean angle. Cornering ABS uses the additional information that’s provided by an inertial measurement unit (IMU). Experts tell us that the IMU’s accelerometers and gyroscope measure speed and lateral (side to side) movement data to allow the IMU to sense how far and how rapidly the motorcycle leans.
Industry analysts say IMUs are a game changer for motorcycles. Although their application is limited to high-end, performance-oriented sport and adventure touring models, as IMUs are adopted more widely, the number of models that use cornering ABS will increase. Most analysts believe that cornering ABS eventually will replace conventional ABS.
IN TUNE. The usefulness of IMUs goes beyond braking. It used to be that if you wanted to tune your suspension, you did it with tools or, more recently, the twist of a knob. However, four models now employ an IMU that detects the speed of suspension travel and uses that information to decide how far the suspension should travel—how much a shock absorber or fork moves based on road conditions. The accelerometers detect how quickly the shock and fork react and relay the information to the ECU, which retunes and adjusts the ride accordingly. This means that when you ride over gravel, the technology softens the suspension automatically, or when you ride over smooth pavement, the system stiffens.
Kevin Cameron, who is the technical editor at Cycle World magazine, says that, because IMUs will proliferate on motorcycles, they now can be incorporated “at moderate cost.”
IMU technology also allows the 2015 Multistrada 1200 S to provide wheelie control to maximize acceleration. Cameron tried this and found it to be effective. “There are a lot of young people on motorcycles who want to do wheelies, but wheelie control on bikes has a switch, so riders can do what they need,” he says. Also possible: models that are equipped with an LED headlight that swivels into turns. Multistrada’s two unique IMU-based functions add $2,000 to the base model Multistrada 1200 ($17,695).
Every expert and manufacturer with whom we spoke agrees with Cameron about the likely proliferation of IMUs. It seems that the broadest adoption will start with higher priced European motorcycles that cater to more-experienced riders who are willing to spend more for such technologies. (Higher priced models can absorb the cost of research and development more easily than midrange or economy models can.)
Although IMU technology, so far, is scarce for motorcycles, models that have ride-by-wire throttles have become widespread. These models use electronics to interpret the mechanical input of throttle movement. As a result, they enable multiple performance and ride modes, which better match horsepower and traction control to how a motorcycle is ridden. The technology was found in a limited number of models before the motorcycle market bottomed out 8 years ago.
A handful of 2015 models that start at $8,190 now are equipped with ride-by-wire technology. How much that costs is blurred by manufacturers’ bundling of the feature with other improvements. For example, the Yamaha YZF-R6 costs $10,990 with ride-by-wire technology. That’s down from $11,299 in 2006, when it represented a $3,900 price hike from the 2005 version, which didn’t have the ride-by-wire capability.
Sue Carpenter is the motorcycle and auto critic for the Orange County Register and KPCC-FM. She has ridden motorcycles for 23 years and reviewed them since 2006. She also was a motorcycle safety instructor.