Teach me about racing lines

[earthtodan]

I'm just getting into motorcycling after about 10 track events in my car (mostly at Thunderhill) and a decade of bicycling experience. I'm familiar with the fastest way around a corner on 4 wheels - late apex, understeer/oversteer, etc... but I suspect that's all going to change on a motorcycle. I'm learning to ride this month. Please tell me the peculiarities of The Line on a motorcycle so I can pick up good habits from the beginning!

Dan

[budbandit]

I tend to take similar lines but optimize for safety not speed on the street.

[earthtodan]

Umm, how is speed different from safety when it comes to your path? The line that will allow you to go the fastest around any corner is the line that will be the safest to drive at any given speed around that corner. Barring hanging over the yellow, that is.

[Lester Green]

umm, the safest line through a turn on the street may not always be the fastest. road surface, tar snakes, gravel. dirt, oil, debris, all determine the safest line through a turn.

EDIT: giving yourself a margin of error and allowing yourself room to change lines mid-turn if neccasary is one key to survival on the street.

[earthtodan]

Originally posted by Beetlejuice
umm, the safest line through a turn on the street may not always be the fastest. road surface, tar snakes, gravel. dirt, oil, debris, all determine the safest line through a turn.

EDIT: giving yourself a margin of error and allowing yourself room to change lines mid-turn if neccasary is one key to survival on the street.
Okay, but we can't plot the tar lines and rut lines through my theoretical turn. Obviously I know enough to avoid them. Nor am I advocating always going as fast as you can through turns and leaving no margin for error on the street. I'm asking about the vehicle dynamics component of the line. Like, do you apex late, or do you apex in the middle?

Going a given speed through the turn, the ideal line will give you the most margin for error and therefore be the safest. I'm asking about the line.

[Enchanter]

Originally posted by earthtodan
The line that will allow you to go the fastest around any corner is the line that will be the safest to drive at any given speed around that corner.

This is simply not true. The 'fastest line' generally requires a fine balance between traction available and traction required with the vehicle damn near on the edge between the two. When speed is no longer a part of the equation, the 'line' through the corner can then be adjusted for smoother directional changes and less lean angle for a better use of traction and hazard management. Many people determine lane position based solely on the road surface and fail to consider the roadside hazards.

Originally posted by earthtodan
Okay, but we can't plot the tar lines and rut lines through my theoretical turn. Obviously I know enough to avoid them. Nor am I advocating always going as fast as you can through turns and leaving no margin for error on the street. I'm asking about the vehicle dynamics component of the line. Like, do you apex late, or do you apex in the middle?

Going a given speed through the turn, the ideal line will give you the most margin for error and therefore be the safest. I'm asking about the line.

Racing lines for cars and motorcycles can be different in some corners and similar in others. It really depends on the turn (or group of turns), the car (to a lesser extent), and the drivers skill level.

To answer your question:
On the street, I generally late apex most turns. At the track, my line is determined by the corner and my skill level.

[Yody]

motorcycles are way smaller than a car, you have 10x more line choices. Don't use up the whole road trying to use race lines on the street. Even on the track people on bikes do not even use up the whole track. Going from white to yellow line on the street is a bad habit. Always late apex on the street and take right hand turns at about 80% because if you go wide on a right hander you are going into oncoming traffic.

On the street for the most part taking a late apex allows you to straighten out the turn somewhat and will give you an advantage on blind decreasing radius turns. On the track of course most turns you will also late apex but it will really all depend on which turn you are talking about. on the back stretch of T-hill you don't want to late apex 6,7,8,9 because you are going really fast, but turns like 4,5,11 you will want to turn in a little later than usual.

[MrCrash]

There are probably a few similarities between car lines and bike lines - I think Holeshot or Oliver can explain the differences. Both of them have a fair amount of experience taking four wheeled vehicles around closed courses.

The best line generally opens up the radius on the exit, allowing you to pick the bike off the edge and put the power down for the best drive. Late apexes accomplish this most of the time, but not all of the time.

[MrCrash]

Originally posted by yody
On the track of course most turns you will also late apex but it will really all depend on which turn you are talking about. on the back stretch of T-hill you don't want to late apex 6,7,8,9 because you are going really fast, but turns like 4,5,11 you will want to turn in a little later than usual.

I'm actually still apexing 6/7/8/9 fairly late.

My apex for 6 is the second to last white stripe on the curbing.

My apex for 7 is where the turn starts to straighten out. You can early apex it at a slower pace with no consequences. Early apex it at an A pace - especially on a 750 / 1000 - you're gonna load the heck out of the front on the exit trying to get the bike turned. At best, you'll lose drive off the corner. At worst, you'll lose the front and lowside. The turn actually crests and drops on the exit, taking away from your available traction.

My apexes for 8 and 9 are about 2/3 of the way down the candy stripes on the inside.

[earthtodan]

Okay cool, now we're getting somewhere.

This is simply not true. The 'fastest line' generally requires a fine balance between traction available and traction required with the vehicle damn near on the edge between the two. When speed is no longer a part of the equation, the 'line' through the corner can then be adjusted for smoother directional changes and less lean angle for a better use of traction and hazard management. Many people determine lane position based solely on the road surface and fail to consider the roadside hazards.

Let me clarify my question: I'm not actually asking about real-world conditions, and I'm not making allowances for steering around the manhole cover conveniently placed in the middle of a turn. I'm also not taking into account driver skill as a variable. I am supposing an ideal, flat, constant radius, recently paved turn at a racetrack. Let the real-world conditions come later! We need a reference point for the line first, and we can make adjustments later.

If you open a car driving book, such as Faster, it will lay out a situation like this and describe the ideal line for this theoretical corner. There are not 10 different fastest lines. There is one fairly simple universal concept that you can use for any corner, adjusting accordingly for conditions.

Yody: Yeah, those guidelines at Thunderhill are pretty much the same for cars. Turn 8 is a mid-apex turn because you gain traction as you start to go up the hill, and you need to throttle on earlier. Turn 4 works wonderfully when you hit the apex pointed almost straight out of it. I'm surprised to see you say that motorcycles don't usually use the whole track. Why is this? On turn 1, for example, I would start on the right, apex late and track all the way out for dear life (if I'm going fast enough). Same for turn 6. It seems to me that since opening up the radius as much as possible will allow you to go faster, using the whole track would be the fastest way.

[MrCrash]

Originally posted by earthtodan
Same for turn 6. It seems to me that since opening up the radius as much as possible will allow you to go faster, using the whole track would be the fastest way.

6 is interesting. I used to set up about 2/3 track out, late apexing it for a really strong drive out. I talked to AFM fast guy Michael Earnest about the line, as I was taking quite a few riders on the exit of 6 into 7. He said:

"If you use that line on me, I will pass you every single time on the entrance of 6. You want to be about 1/3 to 1/4 track out - I can still get the bike turned for a strong drive out"

[earthtodan]

That's interesting. It's these differences that I'm trying to understand. I saw Micheal Ernest race Formula Pacific at Infineon a couple weeks ago, btw, and he is obviously a very good rider!

[PhaTeLeSS]

They're basically telling you that in the car, it's safe to worry about the fastest line through a corner, while on a moto, the best line takes safety into account first, with speed second...

The "Best Line" isn't the fastest, because you have to stay X distance away from the yellow, or the shoulder, etc...

It sounds like right now, you're only asking what the differences would be on a racetrack, or in a closed environment, making adjustments for the real world once you understand the principle?

[earthtodan]

Hey CityBikeMike, this is Dan who used to work at Pleasant Hill Cyclery. Remember me? Josh tipped me off about your identity. If you still work at Cyclegear I might want to drop by and check out some equipment.

[tzrider]

Originally posted by earthtodan
If you open a car driving book, such as Faster, it will lay out a situation like this and describe the ideal line for this theoretical corner. There are not 10 different fastest lines. There is one fairly simple universal concept that you can use for any corner, adjusting accordingly for conditions.
Your "fastest line" does depend on what you're trying to do in that corner. I'm not sure yet where you're drawing the line between theoretical and the context of conditions.

You might argue that my pointing out that turn 2 at Laguna is a decreasing radius turn is an issue of "conditions." Nevertheless, the notion of a constant arc with a late apex breaks down in that turn. Also, that turn is an example of a DR turn preceded by a long straight and followed by a short one. Now we're definitely talking about more than just the turn; the location of the turn relative to straightaways now relates to what you're trying to accomplish.

But setting that aside, a motorcycle offers the best traction it is capable of when the rider is rolling on the gas, producing very light acceleration. Under those conditions, weight is biased in accordance to relative contact patch size and the suspension is in it's proper operating range. A late apex line allows you to get to the throttle sooner and thus optimize traction sooner. Unless there are turn configuration issues that make this approach undesirable for some reason, this is the fastest way through a turn.

[earthtodan]

Originally posted by tzrider

You might argue that my pointing out that turn 2 at Laguna is a decreasing radius turn is an issue of "conditions." Nevertheless, the notion of a constant arc with a late apex breaks down in that turn. Also, that turn is an example of a DR turn preceded by a long straight and followed by a short one. Now we're definitely talking about more than just the turn; the location of the turn relative to straightaways now relates to what you're trying to accomplish.

But setting that aside, a motorcycle offers the best traction it is capable of when the rider is rolling on the gas, producing very light acceleration. Under those conditions, weight is biased in accordance to relative contact patch size and the suspension is in it's proper operating range. A late apex line allows you to get to the throttle sooner and thus optimize traction sooner. Unless there are turn configuration issues that make this approach undesirable for some reason, this is the fastest way through a turn.
Cool, so that means the basic line pretty much transfers over. Use a little acceleration to plant the rear end, and late apex to straighten out your exit line as much as possible so you can start powering out as early as possible. Yes, what you're trying to accomplish is a good point, because if you're setting up for a switchback you want to end up in the middle of the track and not the edge, so the goal is not actually to exit the first turn as fast as possible. In a decreasing radius turn, late apex becomes even more important. I guess all the same principles still apply.

[tzrider]

Originally posted by earthtodan
I guess all the same principles still apply.
One of the biggest differences to me is in control inputs, rather than line selection. A good example is the turn entry. Because of understeer in my car, I have to trail the brakes to get the rotation going, whereas on a bike I don't. On a bike, I'm nearly always on the gas sooner than I can be in the car because I can point the bike quickly once I'm off the brakes. There are situations on a bike where trail braking is handy, but in the classic constant radius turn I find it faster to set entry speed prior to turn-in and be off the brakes as I'm flicking the bike. Cars don't really flick the way bikes do; they typically take a little more time to start turning.

[Yody]

Originally posted by earthtodan


I'm surprised to see you say that motorcycles don't usually use the whole track. Why is this?

A bike is like 1/3 the size of a car, at most speeds the entire track isn't necessary. Think about if you were in car on a track the size of a freeway? wouldn't you feel funny weaving in and out all over the place when it wasn't necessary? Almost everone I see takes turn1 at about half track. For one its just not necessary to start out very wide, also you will get passed and stuffed really bad on the inside if you start out really wide. People who do use the entire track are either really really fast, or a complete hazard to every rider around them. Its very aggravating and unsafe to try and pass a rider who uses the entire track.

I'm sure someone else could point out some other reasons why, but this is what I can think of.

[earthtodan]

Actually, the front side of Reno-Fernley Raceway (the part of the track approaching the bowl turn) is easily as wide as a 4-lane freeway, and on my best laps I used the whole track. So yes, wider is better in that case. But not to contradict what you're saying about motorcycles. I'm just trying to understand why it would work differently. In my head, if you were able to turn enough to avoid the outside of the track when exiting a corner onto a straight, you could have gone faster.

[Yody]

Well I suppose I see your point, coming out of turn 6 at Infineon, there is a huge runoff where you can go as wide as you want. Some people decide to get on the gas real hard and go very wide using up all of the pavement, which is a lot. However I have many times over got on the gas a little later but harder and easily passed the people who decide to go extremely wide by getting on the gas early. Also peoples advice and opinions are going to very greatly because different speeds can require different lines and input. So what I tell you might work for my B+ pace but a racer might tell you something different, or an A pace trackday rider, or a C rider.

[earthtodan]

Interesting. Maybe the variable here is the power/cornering ratio of my car vs. a bike. My car isn't real fast (94 Prelude) but it corners real well in track setup, so it's advantageous for me to take the smoothest line possible. Your motorcycle might be so fast in the straights that you shave lap times by setting up sooner and using longer straights. However, that seems pretty unlikely to me. I've seen econoboxes using the former method beat musclecars using the latter method, and by quite a margin.

[slydrite]

the absolute best racing line I ever used is:

"so, I see you really enjoy diamond plate marks on your hands AND knees.........."

[Yody]

No, you can't carry as much corner speed setting up really wide and turning in late using all of the track, well at least in my experience. Where did I say that I don't try to take the smoothest line? If I can enter a turn smoothly and exit hard without using up the entire track, why should I? I mean that is what we are talking about right? Riding line to line? :loco

I'm waiting on someone to explain this a little better. I'm not going to front like I'm an expert, I just know that if someone is going the same pace as me but it riding line to line, I will just pass them on the inside while they weave all over the place.

[earthtodan]

Originally posted by yody
:loco

Yeah same here. I guess if you say so, going wide isn't always the fastest way. It's just counterintuitive to me that this should be so.

[tzrider]

Originally posted by earthtodan
Yeah same here. I guess if you say so, going wide isn't always the fastest way. It's just counterintuitive to me that this should be so.
The widest line usually is the fastest way. Since T-Hill turn 1 has come up, I find a wide line through there to be fastest. You do have to be willing to turn the bike hard there and be on the gas by the time you are crossing the bumps that usually exist mid-track. You do run a certain risk of having someone outbrake you on a more inside line there. That doesn't make the inside line the fastest way through the turn; it makes it the fastest way *into* the turn. Once the other guy passes you, it doesn't matter that he's a little slower, since he took the line and is in front of you.

You can mitigate the risk of this happening by turning the bike very fast and by not overdoing the late apex. You can square off a turn so much that you have to over-slow for the entry. To find the ideal turn point, first pick a late apex TP that works and then turn a little earlier each lap until you're unable to use good throttle control through the turn. If you have to roll out of the gas or tighten your line, the TP was too early. Only push it as deep as it takes.

Turn 6 is a little different, as you're finishing a medium speed right as you're setting up for a left (6). If you keep the bike tight to the right-hand side of the track coming out of the right-hander you won't be able to generate quite as much exit speed and you're obligating yourself to cover more ground. By letting the bike run out to the left a bit, you get more exit speed from 5 and can still make 6 from mid-track. Again, a quick-turn at 6 helps to make that possible.

[Yody]

Originally posted by tzrider


You can mitigate the risk of this happening by turning the bike very fast and by not overdoing the late apex. You can square off a turn so much that you have to over-slow for the entry. To find the ideal turn point, first pick a late apex TP that works and then turn a little earlier each lap until you're unable to use good throttle control through the turn. If you have to roll out of the gas or tighten your line, the TP was too early. Only push it as deep as it takes.



:applause, thanks for clarifying