Exit almost any highway in America and, what starts as a seemingly innocuous high speed sweeper, quickly tightens its radius. A corner that's tighter on exit than it is on entry presents unique challenges to the motorcyclist, particularly in traffic or inclement weather. Here's how to safely handle decreasing radius corners on your motorcycle.
Step One: Understand The Challenge
Ride in virtually any other country and you'll quickly discover that road designers from China to India to Russia to Mexico know the dangers of the decreasing radius. They avoid using them whenever possible. But here in the country that invented the highway, we've inexplicably baked them in to our road design, making them omnipresent through all 50 states. Of course, you'll find them on other types of roads too, particularly in the mountains. That means we Americans need to pay particular attention to the decreasing radius; its mastery is key to safely negotiating our roads.
Decreasing radius corners are particularly challenging both because they're deceptive, drawing you in to what looks like a fast sweeper, then forcing you to shed speed while cornering. A tire's grip is finite and can be maxed out by either cornering or braking. Doing both together can easily ask for more grip than is available, even at fairly moderate lean angles.
The natural tendency for a rider, when presented with a tighter corner than they're prepared for, is to run wide. But, since these kinds of corners are most often encountered on highway off ramps, that's often not an option as a concrete or metal barrier, or even a steep embankment, border most.
Decreasing Radius Corner
Step Two: Ride Aware
The easiest way to avoid being caught out by a suddenly tightening corner is simply to avoid being caught out. Look far ahead, planning your movements well before it's time to make them. When approaching an off-ramp or corner, try and look through it to the exit, even if that exit my be way off to the side or behind you. Use reference markers like road signs, street lamps, telephone poles and other similar indicators to try and catch any early indication of where the road may be taking you. Entering any corner as wide as safely possible is an easy way to increase the distance you can see ahead.
Step Three: Slow In, Fast Out
The safest approach to negotiating an unknown corner is to enter it at a conservative pace. Even if you're out riding with buddies who are already familiar with a road, you'll be able to make up ground by accelerating earlier than them. You can always try and get your knee down later, when you're intimately familiar with a corner and its unique challenges.
Step Four: When To Use The Brakes
Rapidly chopping the throttle or applying the brakes will cause the bike to heave forward, potentially overwhelming available grip and spitting you off. If you've listened to all the above advice, and are still caught out by a corner, your best bet is to skip to the tip below. But, if you've already learned the fine art of trail braking, then decreasing radius corners are the perfect time to employ it.
Because a decrease radius corner begins gently, then tightens, an advanced rider won't need to shed speed until they're well into the corner. And they can do so by employing the front brake only, slowly applying pressure to gently sharpen the suspension geometry and expand the tire's contact patch. This increases available grip, allowing you to brake and corner at the same time.
Employing trail braking, you're able to perfectly match speed to the tightness of the corner, decreasing that speed as your lean angle increases and slowly fading off the brake as you do so.
The same method applies to decreasing radius corners even if its raining. Just go slower!
Step Five: Trust Your Bike
It's more capable than you are. Look where you want to go, don't do anything sudden with any of the controls and, even if you're caught out by a tighter corner than you expected, you should simply be able to lean way over and ride it out. Without jumping around or otherwise upsetting the bike try and hang off as far as possible, moving your torso way inside the bike's center line, thereby decreasing the lean angle necessary to make the corner. Relax, you should be fine.
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