Tuesday, August 5, 2014

Throttle Like a Rheostat

No, not a throttle like a Linda Ronstadt, or even a Heart Like a Wheel.  A throttle like a rheostat, sort of like the dimmer switch on the wall in your dining room, or the volume knob on your old Pioneer stereo receiver.  Turn it one direction, you get more.  Turn it the other direction, you get less.

Doesn't the throttle on your motorcycle already work that way?  Maybe.  Does it behave in a linear fashion in both directions so that when you roll the throttle on, the bike accelerates, and when you roll it off, it decelerates in a similar fashion?  Always?  Sometimes?  Never?  Is it possible that you're doing something else with the controls of your bike that influences whether your throttle behaves like a rheostat? 

I used to be a little lazy with my gear selection on my BMW R1150R.  It was pretty good at tractoring out of turns when I was a gear too high.  It was easy just to let it pull, even if it shook a bit in the process.  Besides, I didn't need to have it in the meat of the powerband to ride fast enough.  There was no issue.  Kind of freewheel in, managing my entry with the brakes, then tractor out.  Besides, all those guys on the forum said that I shouldn't slow by downshifting, or my bike would wear out, or I'd adversely impact the rotation of the earth, and that would be terrible.

One day I was following some fast, smooth guys, and I noticed their brakelights rarely came on, and that their bikes were always smooth going through turns, and they would accelerate away from me on the exits, so I began to carefully study what they were doing.  What I found was that even though some of them were riding big lazy twins like mine, they were riding them further up the rev band than I was.  Generally, they were riding their bikes with the motor revving in the vicinity of its peak torque, and what they got for their trouble was a bike that would smoothly and quickly accelerate when they opened the throttle.  Not only that, but because they were riding in a RPM range where their bikes generated significant engine braking when they rolled off the throttle, resulting in notable deceleration.  All this without touching the brakes, or in many cases, even the shift lever and clutch. 

So, I tried it.  What a revelation!  Holy smokes, now I didn't feel like the bike was running away on the way into corners.  Now I could accelerate smartly on the way out of corners.  And perhaps most importantly, now I could carefully adjust my line in mid-corner using the throttle as well as other control inputs, and small inputs yielded results.

But wait!  If I'm running near the torque peak so that if I open the throttle a tiny bit, the bike will accelerate, and if I close the throttle a tiny bit, the bike will slow, won't I just be a big, herky-jerky, wobbly mess out there?  Nope, see my earlier post on covering the front brake as a method to smooth throttle inputs, and all will be good.

You may already do this.  It's a common practice among racers.  However, if you don't already do this, give it a try.  I'll wager it will make you a better, smoother rider (with some practice), and that you'll be unlikely to stall a bike mid-corner because you were in a too high gear.  

No comments:

Post a Comment