Apexing

I know the mantra for autocrossing and the like is to late apex, creating the fishook shaped curve. Fine, and I tend to use it myself most of the time.

But not everyone seems to follow this thinking, and it seems to vary along racing formats.

The circle track guys almost invariably follow curve of the track, just bringing the curve as shaped down to the inside.

Dirt bike racing has the most varied, using a sharp V. Dive straight into the curve, and just as you hit the back wall, snap the bike around and shoot back off the other direction.

Anyone played with any variations of these alternatives when autocrossing or road racing? Just kinda wondering about other folks experiences with this sort of stuff.

I think you need a berm for the dirt bike racing strategy to work.

One variation I have seen in road racing or rally is to really throw a car at the corners and rotate late. Keiichi Tsuchiya and Francois DeLacour are probably the best examples of this.

All depends on tire selection and traction. Some times on a bike you have no choise but to "back it in" then take off. http://www.supermotoracer.com/SMR%20Tech%20stories/iss2_backitin.pdf It so much cooler to see on dirt. http://1.bp.blogspot.com/_cLr5JjnwJi4/SwxiYIQCz9I/AAAAAAAABb4/XBcb2zo2840/s1600/porkchops+003.jpg Defending national champ Carroll Resweber muscles inside Bart Markel while Joe Leonard runs the high line . . all on factory 250 Sprints. Check the 2010 AMA Grand National Dirt Track schedule on www.amaproracing.com The pros are coming back to Canterbury Downs in Shakopee. It's a "loose cushion" mile event !

With stock car racing, the apex , or two are always there. The trick is to set the car up well enough it doesn't look like it. Balancing the car on decel, coast and accel is what makes you fast.

Autocross or roadrace late apex is generally right, but you have to take into account the previous and following corner. Turn 1 at Calgary requires a very late apex to set up for two, which is late apex to set for three, and so on, but coming to the keyhole, you can early apex, because its a throwaway corner you sacrifice to late apex the keyhole so you can set up for the righthander onto the main straight. Which is, as we all know, the most important corner on any track.

An alternate line into turn 7 the Toe of the Boot at Watkins Glen is to use the hill on the outside of the corner to make an extremely late braking zone and apex. You run a little more distance but get a straighter exit onto the uphill straight that's the sole of the boot leading to turn 8. It always reminds me of those motorcross guys chucking the bike into the berm and then pivoting and powering back out.

There is no one perfect line - there is an established "path" and a precise line that varies slightly from that path based on vehicle needs, weather, etc. My ideal line is always one that allows me to be on the throttle before the apex with balance at both ends of the car. How I achieve that might be different than how the guy in the mid-engined car does by a little bit. You see FWD guys go deep, fling the thing around to get turned and drive out straight. The IRS RWD guys have mid-corner stability so you see them go right on the textbook or a little early and the solid axle big HP guys go late and come out hammering. We are talking a small variance but the point being you adapt to what works best to the chassis and conditions. I guess a better way to say it is there is a "Theoretical Perfect Line" but it requires a perfect car and driver. Everyone must approximate as best they can.

I will say that for beginner and intermediate HPDE students - we don't so much teach the fastest line as one that leaves margin for errors. That usually means a little bit later on the entry so they don't run out of road until there are some recovery skills and a little more comfort for flirting with disaster. When folks get to the advanced stuff and can correct automatically without thinking we start talking about going early and using a little throttle oversteer or using a large radius and a little dirt on exit to find time but I like to avoid corner worker questions like "How many fingers am I holding up" and "Do you know your name" so I reserve that sort of lesson for after someone has built a little trust

I still use the stand one the brakes, fling the wheel, hope and pray, stomp the gas approach. What is this "line" of which you speak?

For autocross, some of the corners are relatively large and the speeds are relatively low—meaning that cutting distance can help as well. What that means on a Nationals-style concrete course, I tend to double apex---tightish on entry, allow the car to go wide (to a point) and then bring it back in for the exit.

Giant Purple Snorklewacker wrote: I will say that for beginner and intermediate HPDE students - we don't so much teach the fastest line as one that leaves margin for errors. That usually means a little bit later on the entry so they don't run out of road until there are some recovery skills and a little more comfort for flirting with disaster. When folks get to the advanced stuff and can correct automatically without thinking we start talking about going early and using a little throttle oversteer or using a large radius and a little dirt on exit to find time but I like to avoid corner worker questions like "How many fingers am I holding up" and "Do you know your name" so I reserve that sort of lesson for after someone has built a little trust

Late Apexing is what is taught, and as GPS says, for a reason. At most tracks, the "racing line" has a couple places where turn in is easier. There are also lines that create more defense in a race (blocking or mostly blocking line). Late Apex isn't always faster (although many times it is), but it's clearly safer (more room for error). Rally drivers late apex as a matter of course, because they don't see each turn numerous times.

With rally, a late apex has a couple of big advantages. The first is visibility. You can see more with a late apex than you can an early one. It's easier to modify, too. In the important second half of the corner when you're reacting to what you can see, you're balancing acceleration with cornering, and it's easy to let off on the former. If you're balancing braking with cornering, sacrificing one often ends badly...

Rule of thumb for a road course is to maximize your speed when entering the longest straight. Early apexing will throw you to the ouside of a corner, late apex means you hug the inside of the corner as you exit. So, the apex determines where the car is placed when you exit the corner.

There's an excellent youtube tutorial, do a search for " iracing tutorial " or "iracing driver's school" - it's 8 x 5 minute tutorials on racing technique. There's a few good books on the subject also.

I understand the point of drilling the "late apex" mantra into new drivers' heads, but I do feel it's possibly take too far. After, the whole point of late-apexing is to allow earlier throttle application, thus giving you a higher corner-exit speed(and subsequently higher entry speed into the next corner).

However, with lower-powered cars there becomes a point after which if you apex any later, all you've really accomplished is giving up entry speed into the existing corner. So I prefer to think of it like this: "Apex as early as you can without giving up exit speed."

And as mentioned above, the sequence of corners certainly plays a major role too.

Until they demonstrate some understanding of the relationship between braking - turn in - throttle application - apex - drive out, I spend the first few laps with a new student going over a pretty standard late-apex safety line. It varies a bit depending on the vehicle type and experience level, but it skews later than the fast track day or TT line, and doesn't take defense of line into account.

I'll have them run that line for the whole session and will begin to move the apexes back on the basis of how much real estate they're using on turn exit.

The M3 I was doing track events and TTs w/ before going racing had an understeer problem that I eventually fixed not through suspension settings, but apex placement. I raced motorcycles for years - 1000s of laps of Summit Point in a low HP bike on Michelin GP slicks. I'm still unlearning that line, and its one of minimal braking and early, early turn in. Contrast that with what a season in a Radical on Hoosier bias ply slicks taught me and it's ~completely~ different.

At the last race of the season in the Radical, I was trying to find a way off of the lap time plateau I'd been on since mid-season. I realized I was ignoring some of my most common advice I dispense as an instructor; to go out with fresh open eyes and discard whatever line you've been doing. use what you've learned to place the car where it should be going, not ~where you've been going~.

In Friday practice I went out and tried to pretend I'd never been to Summit Point before. I realized I'd been turning in WAY early in T1, and that by moving my turn in later I was able to push my already pretty good brake marker even deeper. and the new later apex was resulting in excellent drives to T3 to the degree that I needed to reassess my braking there. I moved the apexes forward in 4 and 10 as well, and by the end of the weekend had gone from doing high 1'19"s to a 17" flat.

I think it's easier to figure it out on track as opposed to in an autocross due to the repetition and the speed. The Radical is an aero car, so carrying speed definitely helps grip in a major way in the fast bits (and it slightly terrifying to learn that when it doesn't stick, the cure is to go faster - sometimes) but in AX you're juggling speed over distance and have to suss out when it's advantageous to trim distance in favor of carrying as much speed as possible.

I'm going to try AX again this season to see if racing has made me any better at it. My suspicion is that it hasn't.

Late apex has pretty much always worked for me in autocrossing. Early apex means needing to get back on the power in the turn and that can lead to problems. Brake late, trail brake if you can, apex late and try to have the car pointed in the right direction when you get back on the gas. But I also generally drive a hyperactive lightweight RWD car. Someone driving a high powered FWD monster is probably reading this, shaking his/her head and muttering 'what an idiot'.

Per brought up a good point about autocross, though: if given a choice between higher speed and shorter distance through a given turn, the shorter distance will be quicker just about every time, even if you 'square off' a corner. This means hold it till you see God, then hold it a second longer , THEN brake and start your turn. Trail braking is your friend here, that means you can brake much later since you are still slowing as you enter the first part of the turn.

But when trying to apply that tactic to LeMons I discovered it was actually slower. The best thing to do was to find the 'racing line' and carry as much speed as possible through it as smoothly as possible, not worrying so much about distance. Do all your braking before the turn and late apex it. Of course this is with a lightweight underpowered FWD Honda Civic with marginal grip, gotta keep that momentum up.

With that car it also helps to be able to get into the gas as the turn is rounded, it 'plants' it more solidly than coasting or trying to turn when braking. Just ease into the throttle until you feel it accelerate, then keep easing in the gas to keep that feeling going till almost out of the turn, then firewall it!

yeah to the late apex while a-x'ing... 'cept for long sweepers where distance beats speed ... then I try to hug the cones all the way around ... unless the next straight/corner makes this not so smart