Even a cursory read of the first paragraph of this review shows some obvious “red flags.” First, Mr. Acton says that the motorcycle “did something unexpected;” that the bike “didn’t want to accelerate,” and third, “it wasn’t until the lean angle came within 45 degrees…that a blast of horsepower…lifted the front wheel about a foot off the asphalt.” The entire opening paragraph outlines a series of occurrences where the rider was seemingly not in control of the bike! Not just one hiccup, but a list of events in a high-speed situation that were not in rider control, and it actually surprised him, as Mr. Acton describes it. What he doesn’t say though is the bike was set-up for the racetrack and in the “Slick” mode setting. With a less experienced rider it’s a scary and potentially dangerous scenario.
Even a cursory read of the first paragraph of this review shows some obvious “red flags.”
How often does your bike “do something unexpected?” Except in a malfunction, when was the last time you twisted the throttle and “the bike didn’t want to accelerate,” or how about the engine producing a “blast of horsepower” that unexpectedly lifted your front wheel off the ground?
Of course, it is difficult to know whether a typical street rider would be in a situation on a public road where they might be generating the combination of speed, lean angle, and throttle position that John Acton was applying on the race track, but let’s transfer the experiences he had to a possible real-world scenario: An experienced rider (“he” for simplicity) is having a great day on a new TBW-equipped bike on a twisting mountain road. He is “into the groove,” countersteering and getting some serious lean angles going and the bike is responding in stellar fashion. The rider gets a little overzealous and comes into a left-hand curve too hot, but as he is an experienced rider, he has the presence of mind to lean the bike way over and manages to make the turn. But as he starts to countersteer and apply throttle to right the bike when coming out of the turn, the bike doesn’t obey…and faced with an emergency, the rider immediately applies more counter steer to get the bike upright in order to brake. All of a sudden he gets a blast of horsepower. At that point, if he is not able to get the bike back under control very quickly, the rider is likely to crash. A far-fetched scenario? Not from what was described in Mr. Acton’s review.
Without intending to single out BMW motorcycles, the problem is obvious: an engine control system that can apparently usurp operator intent, and, as it seems, possibly initiate a series of events that could cause unexpected alteration of a rider’s control of the machine. This could occur at a time when the rider must fully rely on the physics of how the machine will behave and the expectation of how it will respond at a very critical control point. While those who design these systems would be reticent to admit that this is a loss-of-control situation, it is hard to believe that the hypothetical of the rider on the mountain road described previously could never happen. The expression “that could never happen” is often used to assure the public, and everybody knows how it usually turns out. In fact, the extra cable on push-pull throttle-cable systems was a safety measure employed to be able to close the butterfly in case of cable or other malfunction in the carb.