Playing with speed to adjust radius, respecting the “red circle of direction”
here’s an important secret to enjoying long-radius corners: realizing there is a direction change 60‑75 percent of the way through the corner. For this direction change the bike needs to be slowing. Quicker riders will use the brakes, cruising riders will just roll off, but in both cases the bike needs to be slowed relatively late in the sweeper to repoint it for the exit. Respect this “red circle of direction” and you will eagerly look forward to every long-radius corner. Let’s take a look.
Below I’ve drawn some examples of long-radius corners, commonly referred to as “sweepers.” I’ve added colored lines to show control use:
- Braking (red)
- Deceleration or coasting (yellow)
- Neutral or maintenance throttle (blue)
- Acceleration (green)
- Red circle shows the all-important, relatively late direction change
Example 1: Freeway-entrance awesomeness! This rider guides the bike into the on-ramp with the brakes so the bike turns in nicely. As the bike slows and the rider gets happy with her direction, she picks up “neutral” or “maintenance” throttle, meaning her bike is no longer slowing but it’s not yet accelerating; it’s maintaining its speed and thus its radius. Plan to use neutral or maintenance throttle frequently in long-radius corners.
She wants to have her bike a little wider to set up a nice exit, so she opens her radius (at the same lean angle/risk level) by accelerating gently. As she approaches the all-important direction change (red circle), she rolls the throttle shut and picks up light braking; the bike slows, turns, and points. She initiates throttle to stop the bike from turning when she’s happy with her direction, maintains her speed for a moment to leave the bike on line, and then fires her bike onto the freeway as she takes away lean angle. Fun, repeatable, safe.
Example 2: Freeway entrance drama! This rider mistakenly believes brakes are bad so she turns into the on-ramp off throttle, coasting in and making the corner fine, but not very precisely and certainly not repeatable day to day—a problem if tomorrow there’s debris at the entrance. Ever seen that? Yeah, me too.
She then remembers somebody telling her to “power through the corner” and “accelerate through the corner” and “balance the bike with the throttle.” She never heard about “radius equals mph,” so even though the radius of the corner stays constant, she initiates accelerating throttle and starts to drive the bike through the corner. I show it running wide, but the other option is a loss of traction if she tries to add lean angle as she accelerates. See: “100 Points of Grip.”
Radius equals mph and 100 points of grip: Prioritize those two approaches in long-radius corners or you might decide to quit riding because running off freeway on-ramps isn’t much fun. Wait, there’s another option that leads to non-riding: slowing to a crawl in all corners. Common responses include, “I’m just gonna drive my car next time,” “I hate holding up traffic on my bike,” or “It isn’t fun.”
Examples 3 and 4: How we get to the red-circle direction change can vary depending upon corner layout and rider speed, but no matter how we approach the late-direction change, we must respect it. That means the bike slows to tighten the radius and get direction. Faster riding or tighter corners will require more braking. Cruising easy with a passenger well below the tires’ limits might just require a throttle roll-off, but that red circle must be respected.
In both of these examples, the rider uses the brakes through the direction change, slowing the bike late in the corner to get direction. Safer, faster, and so much fun. This rider will stay hooked on motorcycling for a long time.
Example 5: This rider heard, “Do all your braking in a straight line,” “Get off the brakes before you turn in,” and “You should be either braking or accelerating—no coasting.” So he gets off the brakes, the fork rebounds into poor steering-geometry numbers, and then he initiates throttle just after turn in. The steering geometry of the now fully extended fork tells the bike, “All the cornering is done; it’s time to accelerate off the corner. Let’s go!”
Notice how those techniques work “okay” for a 90-degree corner but not in this hairpin. And when he gets off the brakes before the turn-in, the front-tire contact patch gets smaller too. So the faster this rider approaches the corner, the worse this “technique” will work. Not fun. “This sucks,” he might say. “I’m gonna quit.”
This rider might have been okay if he left the throttle shut and let the bike lose speed longer, but the best, safest, and most repeatable way would be to leave the brakes on past the turn-in point. See “The Brake Light Initiative” and my articles on trail-braking.
If this rider survives this episode (no car in the oncoming lane), he might still quit riding because he believes, “I don’t have the ability to ride.” In fact, he is trying to ride with significantly flawed techniques. Our industry grows when riders stay safe and enjoy riding. There’s a wonderful world of riding enjoyment, safety, and industry growth, and it revolves around brake use. In this case, it revolves around respecting the red-circle direction change in long-radius corners.