Throttle control has been a popular topic of late in our Riding Skills Series. Andrew Trevitt described how small throttle openings settle a bike’s chassis in the May ’10 issue, for instance, and then more recently discussed throttle percentages and corner exits in the March ’13 issue. In both cases we briefly referenced abrupt throttle inputs, but did not elaborate on how on/off/on transitions can affect traction limits and lap times. Here, in contrast, we’ll take a closer look at how throttle control can minimize the chances of a highside crash, reduce lap times and make any given corner less work.
Before we get too far into the right-hand-related aspects of throttle control, let’s first consider the role that your bike plays in a mid-corner scenario; a perfectly injected, 120-plus-horsepower sportbike is challenging enough to hustle around the racetrack, thus one with hiccups at small throttle openings can be detrimental. The primary concern of course is that imperfect fueling will cause your bike to accelerate abruptly, which will subsequently force you to close the throttle and slow down. If your bike falls on the latter, less manageable end of the fueling spectrum, consider reworking the motorcycle’s fuel map on the dyno and with an aftermarket fuel controller. All other things equal, you should notice that the more refined fueling characteristics make it easier to modulate the throttle through a corner.
Multiple on/off throttle transitions...
Multiple on/off throttle transitions through the middle of the corner put a lot of stress on your suspension and also on the tires. This can ultimately compromise traction and cause a rear-tire slide. Controlling that slide will generally not be as easy as Alvaro Bautista makes it seem.
It’s important to also understand that superb throttle control correlates with your riding position. A rider who plants his feet firmly on the footrests and relaxes his upper body will be better able to manipulate the controls for example, whereas the rider who tenses up, locks his arms and grips the bars tightly will make unwanted throttle inputs. Support your upper body with your torso while simultaneously gripping the tank with your knees and you’ll ideally have more control over your inputs.
One of the reasons why we place so much emphasis on controlled inputs and smooth transitions is because an imperfect right hand can cost you valuable time through a corner, and in worse cases, could trigger a crash. The problem is that while at maximum lean, you are using all of your tires’ traction to corner; if you attempt to settle the chassis by opening the throttle, but open it too abruptly, you will quickly exceed the tires’ traction limits. In all cases, bigger throttle inputs need to be matched by a decrease in lean angle.
Uncontrolled stabs at the throttle can also make a turn feel more physically demanding than it really is; the increase in speed causes the bike to run wide, which you’ll have to compensate for by letting off the throttle and muscling the bike down toward the bottom of the track. Riders sometimes recognize this problem but do not understand how to fix it; typically they make the same mistake multiple times through a single corner, which only adds to the amount of effort that they exert over the course of a lap. What’s more, an inconsistency in throttle inputs through a corner will load and unload the bike’s suspension, which further increases the chances of an accident. As the Geek puts it, “Once you close the throttle mid-turn, the corner is done. You simply can’t make up the time that you’ve lost."
This data is for two riders in turn 2 at Willow Springs International Raceway; top traces are speed, bottom traces depict throttle position. Notice that the more experienced rider’s initial input (blue trace, around the 1450-foot mark) is small, but that he never closes the throttle completely throughout the corner. The less experienced rider (red traces) opens the throttle later, only to realize that he’s slowed too much and grabs a handful of throttle. At the 2000-foot mark he realizes he’s going too fast — and likely off line — so he closes the throttle. The process repeats two more times before the exit of the corner. The more experienced rider is 1.5 seconds quicker through this section, and also less likely to suffer a highside crash.
A look at Figure 1 confirms the advantages of a steady throttle through the middle of a long, sweeping corner. The data, pulled from two riders in turn 2 at Willow Springs International Raceway in Rosamond, CA, displays speed for both riders (top two traces) as well as throttle position (bottom traces); the more experienced rider is represented by the blue traces, whereas the less experienced rider is characterized by the red traces. Notice that the two riders close the throttle around the 1400-foot mark, but that the less experienced rider enters the corner faster than he’s comfortable with and consequently takes longer to get back to the throttle. When he realizes that he’s slowed too much (around the 1600-foot mark) he grabs a bunch of throttle and subsequently increases his speed so that he’s almost carrying as much speed as the faster rider by the 2000-foot mark. The burst of acceleration is too much however, and the slower rider runs wide and then closes the throttle in an attempt to regain control and get back on his desired line. The rider’s speed slows in the subsequent section of track, and he repeats his mistake both at the 2400-foot mark and at the 2600-foot mark.
One way to avoid multiple...
One way to avoid multiple on/off throttle inputs is to look further down the track rather than just inches in front of your tire. The latter option generally causes you to “act in the moment.”
The more experienced rider, in stark contrast, opens the throttle just once (around the 1450-foot mark) and subtly modulates it through the corner to maintain a comfortable speed, but never closes it completely. Between the point where the throttle is closed entering turn 2, at about 1400 feet, to where the throttle is closed entering turn 3, at about 3500 feet, the more experienced rider is 1.5 seconds quicker — a huge amount for just one corner. Notice also that the more experienced rider is asking less of the rear tire at the exit of the turn because he’s going from 40-percent throttle to 100-percent throttle, whereas the less experienced rider is going from just 20-percent throttle to 100-percent throttle in a relatively similar amount of time. The conclusion, therefore, is that a smooth initial throttle input followed by more consistent inputs, is far quicker and safer than multiple on/off transitions.
Being smoother with the throttle through the middle of a corner requires a good amount of diligence. Begin first by making sure that your bike’s fueling is the best it can be and also by double checking your riding position. Remember, in a perfect scenario your upper body will be relaxed, allowing you to easily work the controls. From there, focus your energy on looking down the track toward your reference marks and avoid using the front tire as your focal point, as this will generally force you to “act in the moment” and be inconsistent with your inputs. Pay attention also to how you modulate the throttle, remaining mindful of the fact that aggressive stabs can put you on the expensive side of the traction circle.
Some riders may argue that throttle control takes a surgeon’s touch, but in reality it’s more about being mindful of your inputs. Even with the advent of rider aids, it’s still an important skill to keep in mind, as it clearly pays dividends not only in quicker lap times but also in added safety.