[Fundamentals] RRW #4: Slowest Point of the Corner
The fourth in a series of articles originally published in RoadRacing World magazine.
The Slowest Point of the Corner, a term I coined in the mid-2000s, was and remains the single most important component of understanding what it takes to go fast in motorsports — whether in a car or on a motorcycle. When I was decoding this sport, trying to understand what it takes to go fast, I initially spent a lot of time focusing on corner exits and entries, but struggled to identify how they were linked. When did they come together? What were the relevant report cards? What about different radius turns — short, long, how did I know I got it right? It wasn’t until I spent time debriefing with Freddie Spencer and Nicky Hayden while instructing at the Freddie Spencer School that I started to figure it out. This article was an early effort at articulating those thoughts.
Since I wrote this piece over a decade ago, my emphasis on the importance of the slowest point of the corner has only increased.
The Slowest Part of the Corner
By Ken Hill
I needed one second. Actually, I needed more than one second as that would only get my laptime equaled to the fastest rider…and of course I wanted to be faster than that. I was nearing the end of my second day of two days at Mid-Ohio and time was running out. I was sure my drives were strong, I could feel the back squirming around as I tried to get to wide-open throttle sooner and sooner. I was satisfied with my braking, I was building strong brake force, enough to feel the bike starting to move around under me as I neared my maximum brake force. My lines felt good, I was hitting my entry and exit apexes and using the entire track when called for. I had two sessions left, where was I going to find that second!
The first thing I did was to get out my trusty track map to see whether I was taking advantage of every exit and entry corner. Crud, pretty dialed. (You did read KH Clinics 1-3, right?) That precious second I was looking for was getting harder and harder to figure out. The next thing I did with my track map was to put a mark at where I was letting off the brakes and another mark where I was beginning my drive. In between those sections I looked to see how long I held neutral throttle, neither decelerating nor accelerating. In the shorter radius turns, there was very little or no neutral throttle, nothing really to be gained there, but looking at the longer radius turns, Turn 1, Turn 4 and Turn 13 I had a ton of neutral throttle…I just found my second.
What this sport all boils down to is - getting to and from the slowest part of the corner in the least amount of time. Let’s define what the slowest part of the corner is: The slowest part of the corner is the end of the deceleration zone and the beginning of the acceleration zone. The slowest part of the corner should also be where your direction change is complete. The goal is to make that slowest part of the corner as short as possible, optimizing your entry speed and optimizing your exit speed. Sure, there are corners where the radius of a corner is so long that the slowest part of the corner lasts a long time, (Road America Carousal, Infineon Carousel, Willow Springs Turn 2) but it’s the same goal, make the slowest part of the corner as short as possible.
Let’s take a step back and fit this into Exit and Entry corners. With Exit corners, the slowest point comes early, before the apex to take advantage of what the Exit corner offers, acceleration. With Entry corners, the slowest point comes relatively late, at or past the apex to maximize the entry. This is a great tool for understanding what control you should be using at what time. Exit corners, get it slowed and pointed early so the throttle can used to drive off the corner. Entry corners, maximize entry speed by carrying the brakes to or past the apex.
The slowest point of the corner is also where you should have maximum lean angle.
Now let’s fix my problem and find my second. Turn 1 at Mid-Ohio has a very long radius and is an Exit turn. I was getting off the brake too early, essentially setting my speed for the corner way before I needed to, my slowest point was too early. By using the brakes lighter and longer, closer to the real slowest point of the corner, I was able to make the transition from brake to drive throttle almost instantaneous, using zero neutral throttle. My time away from the slowest point stayed the same, but my time to the slowest point was reduced because I carried more speed in to it. This was almost half the time I needed, in one corner!
Once I figured out Turn 1, I used the same technique in Turns 4 and 13 and there was the rest of my laptime…and a little more. This all became even more apparent in turn 4-5, the Keyhole, I was never quite satisfied with my exit onto the back straight, it was good, but it wasn’t what I would consider to be great. By making my slowest point of the corner later and more defined, the bike had a better trajectory for the exit that allowed me to get to full throttle significantly sooner. A huge bonus since it leads onto the fastest part of the track. I was now faster in and faster out.
Next - Putting it all together.
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