Cornering Line / track vs. street

[Greg]

First off, please forgive the very crude Microsoft Paint jpg. Art was not my forte' but I think this drawing gets the point across so please don't get bogged down in critiquing my drawing.

Also, for the purposes of this post, the road that you see drawn is the right lane of the road, not the entire road. As to my way of thinking, the oncoming lane is never an option for me. YMMV.

The "line" you see drawn on the left is similar to a race line (I know it's not perfect, so you type A racers just chill  ...it's close enough for the purposes of this post). I've seen some folks take this line on the street. I would purpose that eventually this kind of line will bite you because the rider is crossing over sets of gravel that are often going to be in the corners.

The "line" on the right is the safer line IMO, as you are following the cleaner "lane" of the corner. You're following where the cars tires have cleaned off the corner gravel.

Thoughts?


Bored in the office   ,
Greg

[Ray916MN]

When I think about riding on the street, assuming a single turn, not a set of switchbacks, there are two different aspects of picking a line:

- whether to "apex" or ride a single tire track
- if apexing, whether to apex early, late, or optimal.

The second diagram shows the single track line. In other words riding a single tire track, and not apexing the turn. Your line is dictated by the curvature or the turn, not where the apex is. This is the safest strategy to avoid gravel or other road debris, relying on cars to have cleared the tire track.

The first diagram shows a late apex line, which might be appropriate in a tight blind switchback. The reason to cross between the tire tracks would be to set up in the biggest radius tire track for an upcoming left hander following the right hander. The other reason to use the second line is that you can see that the road is clean and you want to go through the turn with more speed, so you hit the gas and snap the bike in towards the apex, so you have more room at the exit and have room for more exit speed.

I would agree that for a single turn, where gravel or road debris are potential dangers, that the second diagram is what you want to initially shoot for, but once you can see that the road is clean, the first diagram is going to enable you to go through a turn faster. There is not necessarily a safety difference between the first and second diagram lines. The diagrams to me, are more options, that you have when you take a late apex line.

With respect to apexing, generally on the street, a late apex is the best strategy to use. Both diagrams show a late apex line. All things equal, late apexing is a slow in, fast out strategy. It allows you to get the best view through the turn, before giving it the gas and diving for the apex. This line is typically used by racers to pass, when they have more power, but less cornering speed and/or brakes than the bike they are trying to pass.

The optimal line is the fastest way through a turn and is what someone with superior cornering speed is likely to use. While this might be the fastest way through a turn, it is unforgiving of too much entry speed and doesn't provide the best view through a turn so that a rider can see road debris or decreasing radius.

The early apex line is the fast in, slow out line and is the line used when a rider has superior braking capabilities. The objective is to get in front of a rider being passed at the entrance to a turn,  blocking him in the turn to execute the pass. This line is unforgiving of too much entry speed, decreasing radius turns and provides the worst view through a turn to anticipate road debris or decreasing radius.

FWIW

[Jared]

Agree with Ray that on diagram 2 the line is the safest line from a gravel/sand perspective.  On diagram 1 assuming that the best line is the fastest there could be a ton of different lines through depending on how you wanted to set up for the next turn, what the camber is etc. 

P.S. This post is designed to support non-novel length answers to questions on the board...VIVA LA REVOLUCION!!!
P.P.S. Two track related questions in two days?  Something must be afoot.

[Elk]

Great response, Ray.

The question and your response should be a sticky.

[beedawg]

Line 1 is the style of riding that's taught in the advanced riding courses (like Zars(?) and the like), is it not?

Line 1 is not recommended by ZARS, or any other riding course, as far as I know.  Most "advanced" riding schools encourage late turn-in, but nothing like the first diagram shows.

The attached diagram is from Lee Parks's book Total Control.  The red line represents an early turn point and the green line represents a delayed turn point.

Brent

[beedawg]

Though your "official" diagram from the book verifies my original point. The delayed apex turn, as described in the picture you posted, shows the rider crossing over potential gravel. IMO.

Totally agreed.  The rider has to decide whether any gain from "straightening the curve" is worth the potential of crossing over gravel.

[beedawg]

Even the "outside-inside-outside" path of travel recommended in MSF Basic RiderCourses requires crossing the potentially gravel-strewn part of the lane in a curve.

The attachment is a diagram from the BRC Handbook.

Brent

[nOOky]

Since the track is not the street, the safest line is one that gives you the ability to handle the corner despite any obstacles that come up. If you can't avoid something because you are too committed to turning, you're going too fast for the street.I am guilty of this occasionally, and if I run a turn wide because of a line of gravel across the road, I kick myself because crossing that center line could be death.
Bicycling on the good roads a lot shows me that quite a few drivers cross the center line also, another potential danger. Classes like ZARS and ridingcourse.com teach you that you can make the corner if you come in too hot, and are well worth the time even if you never ride anything other than the ABC's.

[Elk]

Bicycling on the good roads a lot shows me that quite a few drivers cross the center line also, another potential danger.

An excellent point.

Many drivers cross the center line on the inside of turns.  Often these are not aggressive drivers, but drivers that are uncomfortable with cornering; they overcompensate.

This often occurs on simple freeway turns as well; drivers hugging or crossing the lane on the inside of turns.

[Jared]

hehe, nothing afoot. The track still holds zero interest for me.

I agree with the responses that diagram 2 is the safest line to take if you're doing a full day of the twisties. I would encourage newer riders (again, this is only my opinion) to not ride in corners like diagram 1 unless you preride the corner to check for debris. Line 1 is the style of riding that's taught in the advanced riding courses (like Zars(?) and the like), is it not? So one could argue that if it's drilled into your head by these classes to corner like diagram 1, you're building a recipe for disaster unless you can turn on and off that reflex in your brain for making the choice when entering a corner.

Greg

When I started doing track days, I actually found it worked the other way around.  My street riding habits (riding the PACE/not using my brakes) were hard to shake.  I'd be putting along the back straight at DCTC setting up so I didn't have to brake for the downhill left at the end and get passed by two or three riders at a time that looked like they were moving at warp speed.  These riders were hard on the gas at the beginning of the straight and hard on the brakes at the end.  The more I rode the track the more I realized that the only thing that track and street riding have in common is the motorcycle, they are two completely different activities that require different skill sets.  After riding the track for a couple of years I'd say I have different modes for which environment I'm riding in that I can flip back and forth between.  There are definitely some skills that are useful for both activities too.

I guess it would be likely that if a rider had started out on the track first and then switched to street riding then they could go through the same learning curve I did in reverse which would be dangerous for them on the street though, but it seems like the migration usually heads the other direction (street to track).

[Cam]

I would encourage newer riders (again, this is only my opinion) to not ride in corners like diagram 1 unless you preride the corner to check for debris.

My thought is that one of the benefits of the delayed apex (diagram 1) is that it allows you to see through the corner before beginning your turn in, thus allowing you to choose the safest line.  In that respect, I think Ray's comments are accurate that one isn't necessarily safer/better than the other, rather they are options you can choose at your turn in point based on what you see in the corner.  Though contrary to Ray's statement, when I'm riding the line in diagram 1 is my goal, but if I happen to find gravel or other road debris I take a line more similar to diagram 2. 

I was also under the impression that a delayed apex was NOT an ideal race line (except in specific situations) because it requires a lower entry speed, and that a central-apex was the best de facto racing line because it's the best balance for entry AND exit speed.  But I'm not a racer and have VERY limited track experience so I'd be happy to get a clarification on that point.

At any rate, it's an interesting topic so thanks for posting, Greg!

[nraforevr]

I've been working on perfecting a system for an outside-inside-INSIDE path of travel, and having a fair amount of success and positive response.

A rider much more knowledgable than I looked at it and said an even better way to say it is outside-OUTSIDE-INSIDE.

Either way, your goal is to finish on the inside. Using this method, the apex and exit are nearly simultaneous.

I don't have time to draw a fancy diagram (though you can find one in the book Maximum Control) but the procedure is to stay outside and ride parallel to the outside line until you see the exit ... or know for certain where the exit will be. (This is not as hard as it sounds.) At that point, turn the bike hard and dive across the lane to make the apex/exit.

Essentially, you're changing lane positions from outside to inside, midturn, completing the corner by apexing and exiting in the same place.

Not only is this great fun (lots of cornering forces for any given turn, and a satisfying finish), I've found it to be reliably safe for marked (center and fog lines painted) roads. Not only that, it accomplishes two things: keeps you away from the typical spots for encroaching traffic (at the entrance in left handers and the exit in right handers) and it capitalizes on the fact that most right-handers are followed by left-handers, and vice versa.

If I ever get out on my bike again in a social setting, I'd be glad to demonstrate this type of line. It works well at DCTC, too.

P