Rolling Speed: How to Carry Mid-Corner Speed in a Kart

If you want to win, there's no way around it. You've got to be really good at carrying lots of mid-corner speed.

Of course, the entry speed is really key. The exit speed is also really key, especially in long straights coming up. But mid-speed corner, it's something you have to kind of prioritize, especially for those corners where, as I said, you don't really have too much of a straight after that. And you may care more about the entry and the mid-corner speed rather than gaining that last bit of time on the exit. So what I'm referring to is those kind of corners where, you know, for example, on your track like Franciacorta going up into turn two, you know, it's one of that corner where you can't really plan too much for the exit.

Why low minimum speed actually ruins your exit

Instead, you have to drive so hard into the corner and carry lots of entry, but mostly minimum speed, so that you get an even better exit. Because funnily enough, if you carry low minimum speed, you will get even a worse exit, because you'll feel tempted to go early on the throttle, and when you get on the throttle you basically put weight on the rear, and that creates kind of understeer on the exit, so you will not have the rotation for that change of direction that you will have right away for another corner coming up.

And that's the same, by the way, in sector two, where you have lots of mid-speed corners where you can't really play for the exit, but you need to focus mostly on the mid-corner. For example, when you go up into turn nine and ten, the double right-hander, you have to carry a crazy amount of mid-speed there, and the problem is that if you are again too slow in the mid-speed you'll feel tempted to go early on the throttle. But that's again detrimental, because it's a downhill corner, turn ten, and if you go on the gas too early it's going to literally create push understeer on the exit, and you will have a really bad change of direction for turn eleven, the left-hander. So this just goes to show you that in many cases mid-corner speed needs to be monumental if you want to have fast lap times and win races. But you know, it's something, to be honest, that you have to feel. You can't just think too much about it. You need to be developing the skill and the habit of just carrying tons of mid-speed in the corners, only thinking about sacrificing it when you have long straights coming ahead.

U-shaped or V-shaped: in speed, not in line

And so exit speed is more important, and you may favor instead more of a V-shaped corner versus a U-shaped corner in terms of speed, not in terms of line, because in terms of line, that's how the KZ drive more like a V-shaped, but in terms of speed you've got to make sure, yes, the U-shape is the way to go for single-speed karts that have no gears, like shifters instead, they can stop more at the apex in a V-style speed shape, whereas the single-speed karts, like Juniors and Seniors, anything from Rotax or IAME X30, you know, or 60 Mini, of course you need to keep up the momentum in the main corner, and the only way to keep up the momentum, and of course the RPMs, is to open up the corner arc as much as possible, and carry as much momentum and mid-speed as possible.

Of course, you know, you have to find the right trade-off, because if you carry too much mid-speed then you will lose on the exit. So I mean, the goal is to carry the maximum mid-speed you can, in that moment, for that grip level, for your grip conditions, from your tires. But you don't want to carry too much, because then it would probably create a big slide. But even if you manage to not make the kart slide, you will probably end up, yeah, just losing a bit too much on the exit. So, as I said, this crazy mid-corner speed strategy is mostly working in corners where there's no real long straight after that, okay, so you should judge that based on the exit straight.

And also, if you have like a double apex corner, that's really important. If you have a double apex corner, you want to carry a huge amount of speed on the first apex, because, you know, the goal, I mean, you still have a lot of time before the second apex in terms of slowing the kart down and getting the good exit. So, again, there's many double apex corners in Franciacorta, and it pays off to carry lots of minimum speed. Whereas, you know, for chicanes, that may not really work. In chicanes, like especially tight chicanes, you may instead carry less minimum speed so that you can focus more on the exit of the second part of the chicane. So it's really important to have a trade-off in a chicane. But in a single corner that again has no long straights, the mid-speed has to be crazy high, especially, as I said,

The RPM argument

single-speed karts, because your momentum is entirely relying on your speed that you carry at the apex, and your RPMs are going to be massively affecting your torque, your acceleration on the exit of the corner. Therefore, if you, for example, in turn two of Franciacorta, if your minimum RPM are, let's say, 9,000 versus a 9,400, of course that 400 difference in RPMs is going to be huge in terms of acceleration out of that corner, and you will pay the consequences, of course, especially if you have a long straight coming up. So yeah, in general, like, momentum is key, RPMs are key. Of course, if you carry more minimum speed and minimal RPMs, but then your exit is bad, then you don't want to do that. The goal is to have both really high minimum RPMs and minimum speed, but also really good exits.

The real reason: a kart has no differential

So there's one concept that you have to remember, especially in single-speed karts: there's no differential in karts. In formula cars and GT cars, there is. And the differential is basically controlling the speed of your rear wheels, because obviously the inside rear wheel has to travel at a slower speed, whereas the outside wheel has to travel at a faster speed. And therefore the differential is basically controlling the speed and making, you know, their outside wheel travel faster, because he has to drive a wider, longer arc, and therefore it needs to go faster. But in karts we don't have the luxury of differentials, and thank god, I mean, that's what makes karts really cool and really fun to drive, and really challenging, because, since you don't have a differential, the goal to rotate the kart as fast as possible is to make the turn on three wheels, and the wheel that has to lift up is the inside rear wheel.

And when you lift the inside rear wheel, basically the wheel spins slower than the outside wheel, which spins faster. And by doing so, you generate rotation. And when you generate rotation, you can get on the throttle sooner, because your steering is straight around the exit, and that's it, you're going to gain lap time. So the whole goal is to lift up the inside rear wheel, even so slightly, so that you can really pick up the good rotation and get a better exit, or also mid-corner, but it's mostly the exit.

How you actually create the lift

So, in order to generate that inside rear wheel lift, it's not really about the setup. Yes, of course the setup plays an effect: the front geometry, you know, how much caster and camber you have, is going to play a big effect, but also the rear, in terms of what axle you run, the rear width, etc, but also the front track width is going to play a difference. But the reality is that most of the effect is going to come from the driver. I mean, try lifting up the inside rear wheel if you're going slow into the corner. It's not going to be possible, impossible, it's just literally impossible. The only way to lift up the rear wheel is by carrying a truckload of speed, and obviously we're talking about mid-corner speed. So you've got to carry the speed so that you can lift up the inside rear wheel so you can actually get a better exit.

You know, it feels counterintuitive, because if you carry less speed, you will feel like, oh, I'm going to get a better exit. But the reality is that you will get a worse rotation, and it's going to affect massively your exit. So yeah, you should chase that inside rear wheel lift, of course, in the slow corners with a very tight radius, so like hairpins etc. You can't chase a rear wheel lift in a fast corner. I mean, let's be honest, that's not something someone should be expecting, otherwise you probably have a big setup issue, because, at the end of the day, you know, the rear wheel lift comes with weight transfer, and aggressive weight transfer comes when you are pushing hard into the corners.

And, uh, you know, when you're pushing hard there's weight transfer, that weight transfer goes to the outside, and so your inside rear wheel unloads and it lifts up. So that's pretty much the thing: your kart is going to like it and get faster if you carry lots of momentum in the mid-corner. And it's not just about carrying momentum, you also need to hold the brakes. For example, in a slow speed corner where you arrive from a long straight and a high speed braking zone, you want to make sure you hold the brakes and you load the kart on the front, in a way, so that you can unload the rear, and so you can lift up the inside rear wheel more easily. It's all physics and racing dynamics, which are really fascinating, and I love to talk about that, but, uh, I don't want to be too long here.

You have to build the trust first

For sure your kart is going to benefit massively from you carrying lots of minimum speed. For this reason, you need to go out there, next session, next time you go on the track, and really force yourself to trust the kart, to trust the grip level, and really push yourself to carry that momentum and lifting up the inside rear wheel. Of course it's gonna come with confidence. I mean, I'm not gonna fool you into saying, oh, you know, you're gonna do that right away, first day you go on the kart. I mean, it's not possible. It's like saying someone who has been riding a bike, like a motorbike bike, for the first time, let's say a MotoGP, is asking him to lean down with 60 degrees just like Marc Márquez or Valentino Rossi have done after years and years of training. So that's not possible, to expect someone to do that if there's no prior experience.

And obviously, build confidence and trust in yourself, but also in the kart, because you can do these kind of things when you feel like your kart is an extension of your body. You need to become one with your kart in order to do these things. So get out there and practice, practice, practice, but also push yourself to do this, because the only way to become one with your kart is to push yourself in a way that you get to become one with the kart. If you never push your limits and you're always driving your comfort zone and below your limits, believe me, you're never gonna manage to become one with a kart. So go out there and push your limits like crazy. You're gonna see the results, they will thank you big time in your data.

What you can actually see in the data

If you open the PURPL app, you can check and see whether you're carrying lots of minimum speed or not. You can normally see, of course, either against yourself, other previous sessions, or you can check against other drivers, that's fine. But normally you can see if you're carrying lots of mid-speed if you have more like a U-shaped line in the speed trace, not in the line, remember, in the speed, or if you have a V-shaped, if you have a V, of course it means you're like stopping the kart more in the mid-corner, which, you know, reduces your RPMs, and therefore your momentum, which is going to be really hard to pick up, especially if you have a lower power kart, like a 60 Mini kart or like a Junior kart. In Seniors you pick up more momentum easily, but still.

It's all about momentum. Like, even if you slide just a bit, or you know, you're not keeping the optimal line, or you're not holding the brakes right, you're missing the apex, etc, you lose a bit of grip, you lose a bit of momentum, your RPMs will drop, and it's going to be harder on the exit. I mean, there's no secret about it, like, the best drivers are the ones who are able to brake the latest, keep up the most momentum in the mid-corner, and then have their great exits, despite really, really good entries and good mid-corner speed. So yeah, you should ideally look for U-shaped minimum speed, so that you can carry the speed, rolling the speed, in a way, without literally stopping and parking it at the apex.

What "rolling" really means, and what it doesn't

But what I'm saying when I'm talking about rolling is you're not planning to come off the brakes and just roll the speed, just like an amateur, a beginner, would do, because that's the opposite of how you should drive. You should brake, for example, in a hairpin where you're coming at a high speed, you should brake late, hold the brakes, and just have a very small rolling transition, like of 0.1, as I always say to my drivers.

You don't want to be with a lot of time rolling, of, as I call it, dead zone, because then it's going to, you know, make you slow, and the momentum is going to kill you, the grip is going to kind of make you stuck there, you're not going to be able to, uh, you know, you're gonna, you're not gonna make the kart flex and lift up the inside rear wheel. So you need to have a very, very, very tight transition, not a large transition. Okay, but you need to have a transition, because if you are, like, on the brakes and then right away on the gas, with not even a 0.1 transition, then it's not good, believe me, because you'll probably end up being too early on the gas, you're not gonna let the kart load, as I like to say, laterally, you will not let the chassis tubes flex properly, and therefore you will not be able to, yeah, just drive out and rotate the kart with the best flexibility, and even, like, almost like a spring.

It's like I always feel, like, when I go in the middle of a corner, I need to hold the brakes, yes, but then I need to have a 0.1 transition where the kart loads, you know, literally loads laterally, kind of flexes, and then springs me out. If I'm not letting that load happen, that 0.1 transition happen, it's just basically going to make me, first of all, not load and rotate. Because when you say load, it's basically letting the kart load and lift the rear wheel. If you're not letting that happen, you know, you're basically, when you're trying to go on the gas, you're basically, when you're going on the gas too early, and you're letting that transition of 0.1, it doesn't have to be one second, it has to be 0.1, where you are letting the kart load, and you know, you're able to let the inside rear lift. If you go on the gas too early, you're not gonna get that lift, you're gonna, the lift is gonna try to happen, but then you will basically put the wheels back down, because when you go on the gas, traction picks up, and you get both rear wheels down, and when you get both rear wheels down, you have, let's say, double the grip level, and it's almost like pushing you on the exit, and you will not get the rotation, because that's the thing, you know, when you have both wheels on the rear, they're not allowing you to rotate the kart as well as just one, which kind of makes no sense, because, you know, we would want to have as many wheels as possible on the track, right? Think about it, like a four-wheel vehicle is faster than a two-wheel vehicle, like, think about it, cars are faster than motorbikes in the corners. But in this case, believe me, it just works out better to be on three wheels in mid-corners rather than on four, because your two rear wheels gonna push you up, and again, you need to have that very small transition of 0.1, 0.2 max, where that transition is lifting up the rear wheel. Obviously you don't have to expect for more, but yeah, it's gonna make the kart rotate more, and when the kart rotates more, you can get a better exit. So rolling is good, but you need to do it very, very little, like 0.1, 0.2, because again, that not only lifts up the inside rear wheel, it also makes the line more U-shaped than V-shaped, and it keeps up the momentum. But you need to have that feeling of when to have that roll, tiny, tiny roll. You don't want to have, again, too much of a roll.

The exception: banked corners

But of course, it depends from corner to corner. There are some corners with lots of banking where you don't really have a heavy braking zone, where you need to kind of roll a lot of speed into the corner. For example, in turn nine and ten of Franciacorta, it's basically a very banked, not very banked, but kind of bank. You know, we don't have so many banked corners, positively banked corners, in Italy. But anyways, you kind of have to go in there, in turn nine, flat out, and just make a tap on the brakes going into turn nine. It's a double apex, basically, like it's no nine in ten, people call it nine and ten, but I really like it to call it as a single corner. And basically you have to kind of go and tap the brakes and just roll, carrying lots of speed, using the banking. So in that case, you're not having a small transition, you will have a bit more of a transition, instead of 0.1 it's going to be like one second of transition. But that's because the goal there is carrying lots of entry, minimum speed, and you will not need to go on the gas too early, because if you do, actually, you're going to generate push understeer, because it goes downhill.

Every corner, every track, has different specific techniques. That's what makes racing so cool and so different, you know, from other sports, is that the conditions change, you have to adapt, you can't treat every corner equal. And so, yeah, in some corners you may work to roll a bit more than usual, in other corners though you need to roll very little, but you still need to roll a tiny bit. If you have zero roll, it's not good, believe me, especially if you have a Junior or Senior or Mini kart, where you gotta try to get that rear wheel lift, especially in heavy grip conditions. You need to have very little roll, but you need to still have a tiny bit. In KZ, it's a bit different, because you V the corners more, you won't have that much of a rolling time, but you still need a tiny bit, just because eventually you still be ending up lifting up the inside rear wheel, but just less.

Hands: push with the outside, don't pull with the inside

Of course, in the mid-corner you always have to remind yourself, in order to keep out a good minimum speed and keep your kart, let's say, locked in, you need to be pushing with your outside hand instead of pulling with the inside. It's really important, you don't want to pull with the inside, because that's not gonna help you, uh, being smooth, it's gonna make the rear overreact. So you want to push with the outside hand, but always remember to have, like, smooth hands overall. The inside has to be super smooth, the outside has to be a bit more hard, let's say, but you gotta be, yeah, just like, remember that push and pull, you need to push with the outside and not really pull with the inside. The inside has to be barely doing the work.

Momentum is the keyword

So you can analyze all of that on PURPL. You can see whether you're carrying a lot of minimum speed or not in the corners. I wish there was a channel that allowed us to see whether the inside rear wheel lifted up or not. I mean, we would need to have multiple speed sensors attached to the rear wheels. It's not really possible, I mean, it's nothing we can do from PURPL, it would be the driver that would need to have those. But yeah, besides that, I'm pretty sure that you can have a lot of value by analyzing the data, and you can still see the U-shaped minimum speeds playing in action, you can see whether your RPMs are staying up or they're going down, and that's all about momentum. Remember, the keyword is momentum. Keep up that momentum, make the rotation really good in the mid-corner, get the kart to rotate by lifting up the inside rear wheel, but you only do that by carrying lots of speed.

And just remember to keep sending it. Ciao, ciao.