Riding Skills: How To Safely Handle Decreasing Radius Corners

How To -


Decreasing Radius Corner

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
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.

More On Page 2 >>

  • Rameses the 2nd

    Most, if not all, ramps have ramp speed posted. Don’t be a MotoGP rider on public highways. Be smart and slow down. If you are going to enter a ramp at 80 mph, you won’t have enough time to think and react.

    • Jorn Bjorn Jorvi

      I was just about to post that. My tip: trust road signs. They suggest a speed for the least competent drivers. Sometimes you’ll be entering a corner and notice a yellow sign suggesting a speed that looks unusually low. This may be a hint to the path after the turn or through the parts of the turn that aren’t visible from the entry. Pay attention to those signs and adjust speed accordingly.

      • Phil Mills

        The first time you’re on a road that advice is gospel truth. There’s a canyon road outside my hometown that’s nominally 35mph but has a few turns marked as 10 and 15mph cautionary speed limits. You LISTEN to those signs, my friend. Narrow shoulders, rock walls, completely blind and prone to oncoming traffic doing who knows what.

        • Ben W

          I learned that lesson on my first trip to real hills and curves (it’s a hike from Dallas!). I came to one posted at 10mph and that was optimistic. Later, our group went through a series of blind turns marked at 35-45. Most of them, you could take at 60+, and everyone got in that rhythm. Lo and behold, one of them really needed to be closer to 45. Every rider before me went deep into the oncoming lane – thank god there was no traffic – and I only barely avoided doing the same.

    • Piglet2010

      Eastbound to northbound here catches a lot of people out – I have drug the right peg feeler on my Dullsville at the exit: https://maps.google.com/?ll=41.797808,-88.28108&spn=0.004319,0.010568&t=h&z=17

  • Luke Applegate

    Isn’t the path shown in the diagram an increasing radius? If you started on the right side and rode the curve counter clockwise it would be a decreasing radius. I could easily be looking at this backwards…

    • APG7

      I agree….this seems flipped.

    • http://RideApart.com/ Wes Siler

      You’re entering a gentle corner that tightens into a long exit. It’s decreasing.

      • therubbersidedown

        Based on your diagram you’re entering an almost 90 degree corner that lessens toward the exit. Increasing radius. Same thing if you look at the inside line of the corner and use a little geometry and create 2 circles at the entrance and exit.

        • http://RideApart.com/ Wes Siler

          Damn, maybe you’re right. Same principle applies either way.

        • infresig

          Sorry for the schadenfreude, but this is a really hilarious error

    • Dragos Ivan

      You are right. this is definetly an increasing radius turn.

    • http://RideApart.com/ Wes Siler

      Alrigth, fixed now. D’oh.

  • gaudette

    slow down

  • lemieuxmc

    Why do you want to drag a knee? Eddie Lawson had to drag knee to keep the hard parts on his Kawasaki from grinding and his tires were crap compared to what you have today.
    Modern bikes have plenty of clearance and grip, if you’re hanging off you are either a ridiculous poser (99%) or you are going WAY to fast for a public road (which makes you a dangerous ASSHOLE!).

    • Chris McAlevy

      because must of us are posers aspiring to be dangerous assholes.

      • lemieuxmc

        See, that’s an appropriate understanding of sarcasm and irony.
        Well spoken Sir.

    • http://RideApart.com/ Wes Siler

      That’s not why Eddie dragged knee…

      You should absolutely hang off a modern bike, not to attempt to get your knee down, but to remove lean angle in pursuit of safety. If you end up dragging your knee, that’s just a byproduct of doing it right and going fast.

      Read this: http://rideapart.com/2013/10/10-things-you-need-to-know-about-motorcycle-body-position-for-sport-riding/

      Sincerely, the knee-dragging asshole in the top photo of the article.

      • V Twin

        Why only a modern bike? I hang off my Mk5 Le Mans, fitted with a 120-90 18 rear.

        Never too old to have fun!!!

        • http://RideApart.com/ Wes Siler

          Because you’re too busy folding your white wool socks over the top of your horse riding boots?

          • V Twin

            “white wool socks over the top of your horse riding boots?”

            Engineer boots! You’ll be saying I ride in Jodhpurs next.

            Two piece Arlen Ness with Tractechs, when riding any of my bikes. The odd local jaunt in denim jeans and armoured jacket.

            Back to the article. I often come across riders who have been riding for many years, and who become confused on certain bends opting to ride the centre line at reduced speeds.
            So this article really does have a roll in liberating a riders potential.

        • Piglet2010

          Heck, I get half a cheek off the seat on my Honda Elite 110.

      • Piglet2010

        Half a butt-cheek off the seat and outer shoulder to the inside of the bike’s center-line works well for road riding – no need to imitate Marc Marquez, particularly on a longer ride.

      • lemieuxmc

        I remember when I was young and dumb…
        Discretion and judgment are often the razor thin margin separating a close call from a trip to the ER or the morgue.
        Strangely, I can’t find your name listed in the latest Moto GP results or as holding a lap record at the Isle of Man.
        Perhaps you should get off the streets and onto the track before I see you on rnickey mouse’s highlight reel.

      • Jorn Bjorn Jorvi

        A bike with modern tires, more appropriately.

  • Twin Verb

    Lean and believe….

  • jeremyobryan

    Trust and obey.

  • Jhon Alexander

    Those aren’t easy that’s for sure…Took me nearly all summer to get it right…Getting off the manhattan bridge into the I-287 W not only does the radius decrease but it’s at an increasingly steep angle….up top there’s also a pothole that seems like it’s been there since the middle ages so you can’t really keep the same line…

    • HellomynameisAG

      I was thinking the exact same turn, or the one getting on Fdr north from the Brooklyn bridge. Oh wait let’s not forget west side highway south from the GWB that all of a sudden splits into 2 separate lanes (one for riverside drive).

      • NOCHnoch

        I kinda love the FDR north turn…reasonable well paved for a NY ramp

      • Jhon Alexander

        Right on!..I live on 175th and work in brooklyn, so I literally have to take all those exact same corners every single day..that split to the WSH gets me every time. getting on the FDR from the BK bridge has definitely some pretty awesome turns… that first right hander is deceiving, but you can gather up some nice speed into that really nice left, then comes that awesome downhill with a great view and smell of the east river!…

        people don’t believe me when I tell them NYC has some great hidden gems, but if you can find those times with hardly any traffic, they’re pretty thrilling, especially on my 748, that thing loves to corner!

        PS…on occasion I take riverside drive whenever I can..great corners, awesome views and super relaxing..WSh is just too full of potholes for me so I take riverside whenever I can…

        I’m surprised as balls I haven’t gotten stopped at all in 3 years..the only ticket I’ve ever gotten was in queens for making a left while driving a commercial truck…go figure!

        • HellomynameisAG

          Totally – riverside drive late at night /early morning is fun.
          I always wish they would open up the Central Park loop for a little supermoto road race!
          The real question is what color is your 748?

          • Jhon Alexander

            I wish!…reminds me of the city’s attempt at bringing F1 up here a while back…cool dreams that will unfortunately never happen ;(

            It’s a 2000 748…had to fly to Wisconsin to pick it up because it was super low mileage and in pristine condition..I plan on turning it into a bone stock track bike next year to refine my skills and test gear and so forth…that thing’s gotten me out of more close calls than I can count…handling is just superb.

            I have my eye on a Daytona 675r as a replacement :)

            pic below

            • HellomynameisAG

              nice man. My girlfriend used to live on grove street in the west village and every morning I would see this beautiful 748 in that same color because it was never ridden. Parked on the street through winter it finally lost some of its shine, I actually left a note asking if the guy wanted to sell because I couldn’t stand it being mistreated and not ridden any longer. Never heard from the guy / girl. oh well. Great bike man, good choice.

              • Jhon Alexander

                thanks!..leaving these bikes to waste away like that should be a crime!…these bikes are meant to be ridden…kinda expensive to keep up with what with so many outdated mechanical components, but a great excuse to learn how to work on your own bike…but you’re right,,had you the chance it would’ve been a great buy..don’t think I’ll ever sell mine

  • Bruce Steever

    Step One: Pose coquettishly at the run-off of a fast street corner. Step Two: Piss in the face of the gods. Step Three: ???. Step Four: Profit?

  • Piglet2010

    A day of lapping the Road America Motorplex helped me a lot with decreasing radius corners. What is not apparent in the aerial view is the corner has about 10 feet of elevation change.


  • Piglet2010

    I would add to step 5 what Jason Pridmore teaches – if you think you are in too fast, look even farther to the *inside* of the turn.

  • metric_G

    When riding an unfamiliar road my two word advice: late apex.

    • runnermatt

      Late Apex = slowest corner entry + safest corning line + earlier throttle application + highest exit speed = most fun way to take a corner!

      • Ryan Deckard

        I certainly agree. I find it much more fun to get on the gas early and experience those g forces as opposed to trail braking into a corner unsure if your speed is too great.

  • runnermatt

    I learned to “trust the bike” while mountain biking. You would be amazed what a bike and its two big gyroscopes will get you through. Give up on the bike OR try and make it do something it doesn’t want to and you crash.

  • runnermatt

    I used to have a good decreasing radius (afternoon/evenings) increasing radius (mornings) corner during my daily commute. This was several years ago, before I started riding. At the time I was driving a 2005 VW TDI that got 46mpg during 40 miles of backroads/interstate (75mph on interstate) and 5 miles of city driving.

    This corner is rated at 35 mph I think. In the increasing radius direction it starts quite tight requiring a large steering input at entry, then allowing you to slowly unwind the wheel as you move through the corner. In decreasing radius direction you have to progressively and smoothly increase the steering angle until you get to the tightest point of the corner.

    I used this corner to work on the smoothness of my steering inputs. I worked my way up to being able to stay in my lane, with only my left hand on the wheel (I’m right handed), and the cruise control set at 60 mph. Why set the cruise control? Because it eliminated my ability to use the brakes and throttle to transfer weight. The mornings when it was an increasing radius were more difficult because it require a large, fast, and SMOOTH steering input.

    • runnermatt

      I will ad that traditionally decreasing radius corners are the more difficult corners. Especially, when braking to the apex or when not expecting a decreasing radius corner and traveling at a speed that doesn’t account for a decreasing radius.

    • runnermatt

      1st picture is increasing radius. 2nd picture is decreasing radius.

  • Afonso Mata

    My rule of thumb for increasing radius or decreasing radius or steady radius or non-existing radius corners is this: “Until you’re intimately familiar with a corner and its unique challenges, SLOW IN.”
    Then, look well ahead, and the exit speed will come.

  • ThruTheDunes

    I appreciate the breadth of riding topics/issues you folks address, and this one is certainly germane here in the northeast. I suppose this should be a heads-up to those of you who travel into our older corner of the country: there are a LOT of these on the entrances AND exit ramps for older highways, particularly in Massachusetts. Up in my neck of the woods, there is hardly a ramp that does not have tractor trailer/dump truck skid marks going off into the dirt or divots left by the grilles of nose-diving sports cars. Add in a little rain and mix in some autumn leaves, and a leaf-peeping ride can become a bummer of a trip (sometimes you need to take a big road to get to/from a good road…). It was so routine to me that I had not given it much thought until one adrenaline-inducing experience when teaching my son to drive (a car).

  • Steve Hall

    We deal with, and ride the Decreasing radius turn all day long at Streetmasters Motorcycle Workshops. The Delayed apex technique basically works in all corners allowing you to be seen by oncoming traffic and see what’s ahead, giving you options in selecting a safe path of travel.
    Basically stay as wide as you can as long as you can, turning your head to actively search for the apex. Once you find it, tip in and accelerate towards the apex. The diagram above is the typical racers line of outside-inside-outside, which we do not advocate using on public roads.
    If any of you are interested in learning this technique, come spend the day with Walt Fulton, Nancy Foote and the rest of the staff on the Horse Thief Mile, Willow Springs, Raceway-Rosamond, Ca. We would love to see you at Streetmasters. www. street masters.info

    Have fun and ride safe,


  • kentaro

    Outside inside outside path of travel, back to good old msf.

  • Abe Norfleet

    This is very bad street riding advice. The illustration is clearly a race line, which takes you through the dirty part of the lane, twice, and if you get the tricky corner a little bit wrong then you end up in the oncoming lane. A prudent street rider would pick one of the car tire tracks, then go slow enough to complete the corner in that line. In a right-hander like the illustration, the left track is better for entry visibility and is less likely to have gravel or dirt kicked up from the shoulder but the right track, while slower and more likely to have some dirt or gravel depending on the shoulder, would leave more space between your meat and oncoming cement trucks.

    Hanging off, knee dragging, slow-in-fast-out, trail braking, and race lines are all for speed, and speed is for the track. Survival on the street is not a sport and you use race techniques at your own peril.

  • ticticticboom

    Relax your arms and kiss your mirror. Focus your eyes ALL the way through the turn, let your bike do it’s job.

  • adrian

    The correct way to handle an increasing radius corner is trailbraking!