Grip vs no grip

What changes do you have to make to your driving when driving with a lot of grip compared to minimum grip?

Thanks in advance🙃

If you haven’t, go watch @Ryan_Norberg getting under the rubber over on yt. Starter for ten :wink:

I have watched it yes, but i dont quite understand it?

Can you explain what is difficult to understand from the video. It is tough to understand without experiencing firsthand.

Essentially, as the track gets higher grip, and more rubber laid down, the “line” of rubber put down from the outside tires gets wider. When you drive on a track with rubber, if you try to cross the “line” of rubber by apexing late, it upsets the balance of the kart and kind of tries to rip the steering wheel out of your hands. As this happens, you start turning in earlier so your outside tires stay on the inside of the rubber, rolling into but not over the grip. This is generally referred to here as driving under the rubber.

It’s also a bit tricky now, since depending on the manufacturer, this rubbering up of the track doesn’t happen anymore, and the track gets what Ryan Norberg describes as polished. This means as the track develops, you actually keep trying to apex late. It’s a very situational understanding, and something that’s more of a “feel” than something you think about once you have it down.

I dont understand what he means by turning in earlier and still apexing the same place and getting on the gas at the same time?

And when i try the technique i just go slower

Well you turn in earlier, but you have to be slower with the wheel input at the same time to keep from working the kart too much at once. This isn’t really something you should be running into unless you’re racing at the national level

getting under the rubber isn’t really something I’ve found very pressing during a practice day but more so during a race weekend. With that said, essentially what is happening is when the race weekend progresses more and more rubber is being laid down on the track. the more rubber being laid down generally the more grip you will have, by “getting under the rubber” you are basically using that sticky rubber on the track to guide the kart into the turn. It is a little tough to understand but when the track is really grippy, like on a race Sunday the kart will tend to grab into the asphalt a little bit more so you can almost let the kart carry itself through the corner and the grippy track will “carry you” around the corner, hence the early turn in and then roll. I tried my best to articulate this as best I could, however, it is really something you have to experience and see yourself. Next race I would watch the guys/girls on the track with you and take notes on how their line changes throughout the weekend. If you are driving slower then I wouldn’t try to change anything, unless you’re in a hyper-competitive field, trying to constantly change your driving style to get under the rubber is very prohibitive to any learning and growth which will make you naturally quicker. Feel free to add/change something I said but It really is something you have to drive to fully appreciate.

problem is exactly when we’re running regionals we’re the fastest, but when coming to danish rotax challenge (nationals) we’re +/- 0,5s off pace

but if you’re turning in earlier how are you apexing the same place?

You let the kart roll, and you don’t turn in as sharp. It’s A slower more progressive turn in. Use smooth inputs on the wheel.

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you all put a lot off emphasis on “rolling” the kart what do you mean by that?

off the throttle off the brakes. Literally letting the kart roll, now this is only for a second or two until the kart is pointing straight and you accelerate then.

Brake, Turn in, roll , throttle - the general break down of taking a corner

So you wouldn’t trailbrake when doing this technique?

I guess you still could, technically most corners have at least a split second of roll time (no brakes no throttle). Getting under the rubber isn’t something I’m well versed in so I can’t speak to that question with 100% accuracy.

Is this against the same competition? Or different drivers?

By turning the steering wheel slower. You’re using the rubber to keep the kart rotating at the center of the corner, getting to the apex. You’re not necessarily hitting the same apex, it’s a little earlier and closer to a middle apex, but still apexing after the center of the corner.

I don’t necessarily think of rolling the kart as coasting at the apex, but going a little deeper under braking carrying a little more apex speed since there’s more grip. You have to make sure you smooth your inputs since any mistake is amplified in high grip.

As a general rule of thumb, I don’t like to recommend trail-braking in a kart in general. Usually you want to be getting off the brakes as you turn in, and back onto the throttle right after the initial turn-in input.

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@eliashoejfeldt do you have any video for folks to review?

@tjkoyen I had once a graphical one-pager of your making that was titled “under the rubber” with a diagram and explanation. Do you recall this?

We’ve just got our hands on a cam, only thing we need is a case, which i hope i can get my hands on before we’re out again tuesday

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Is it possible for you to make a drawing of how the racing line is when using this technique compared to a normal line?

I have a video which explains this in detail.

I don’t know where my graphic went, might be on my other computer.

Basically as stated, you want to aim for the same apex but turn in slower and earlier. This loads the kart up more progressively and it won’t react as harshly. You’re making the turn more of a U rather than a V. Remember that any input you give the kart, it will react the same way and that’s amplified the more grip on the track. Turning in sharply and aggressively will cause the kart to hike the inside rear wheel harder and more aggressively. This becomes a problem as the track builds grip because that aggressive reaction will cause the kart to start to hop or bind up. As grip levels rise, you need to become more progressive and smoother with all your inputs, blending them better and more smoothly so the kart stays at it’s limit through the turning phase, rather than going over that traction limit.

It’s also my preference to NOT coast or let the kart roll as much as possible. Any time you are coasting or letting the kart roll, you are letting the inside wheel sit down prematurely. The kart needs lateral force to help keep the inside rear unloaded, and coasting starts reducing that lateral force. I prefer to have some brake or some throttle on at all times. Not necessarily full throttle or full brake; remember the pedals are not on-off switches. This might mean that you just have 25% throttle on as you roll into it again for a second to let the kart sit on it’s limit and not overwork the tire. This also means I trailbrake for most tight corners, which is generally what most of the really fast guys are doing. The key to being fast using this technique, is to blend those inputs smoothly so the kart is never shocked into an unstable state by aggressive steering or pedal inputs.

The order of a corner should be hard, sharp braking to traction limit → as you start to input steering, start to bleed off the brakes → as you are getting close to the apex you should have gotten the kart slowed down so you are at 0% braking and now are immediately transitioning to throttle input, so as your foot comes off the brake, you are slowly applying throttle to keep load on the kart → as you reach apex, you should be almost at full throttle and now you should be unwinding steering back to center as the kart has achieved rotation and is fully loaded up, meaning you can straighten the wheel and go to full throttle and let it float off the corner.

During that whole phase you need to be keeping tabs on where the grip limit is and modulate each input accordingly to keep the kart right on the limit and not over.

My braking video might be helpful too:

And also this video of me driving might be helpful. Keep an eye on my feet, mostly my braking foot, and notice I trailbrake every single corner at this track: