KTM tech: ‘sooner or later everyone will have carbon-fibre frames’

Last September KTM introduced a carbon-fibre frame, which immediately gave the RC16 the most important thing of all: more grip.

There are many important advantages to using carbon fibre in racing. It’s lighter and stronger than steel and aluminium. Increased chassis rigidity allows the suspension to do a better job, which allows the tyres to follow the road better, which increases grip.

Carbon fibre also allows engineers to fine-tune chassis rigidity, by using different fibre weaves and laying them up in different ways.

And there’s another important plus to carbon fibre, which MotoGP engineers don’t talk about – carbon-fibre chassis components can actually understand themselves.

When engineers lay up a carbon-fibre frame they can lay electrical-conducting plastic fibres within the fibres and weaves to provide data that reveals exactly what kind of forces – bending, twisting and so on – each part is undergoing during every second of every lap. Thus carbon-fibre chassis could revolutionise knowledge of frame behaviour.

For all these reasons – and probably more – KTM is convinced that its rivals will soon switch from aluminium to carbon chassis. Aprilia has already started this process.

I spoke to KTM’s MotoGP technical manager Sebastian Risse at the end of last season to get the inside line on the RC16’s immediate past and future…

Oxley: You go into 2024 after making a big jump forward last season…

Risse: That was mainly a jump forward in consistency, which was our target. Consistency and qualifying positions were our targets and that’s what we saw.

What made that happen?

Working on how we can use the grip – how usable is the grip that we are producing? We worked on this in many different ways, from the engine, through the drivetrain, through chassis stiffness.

On top of this we worked on the electronics, especially with Jack coming into the team, because he came from a background where he was managing the bike a lot on his own, so with less resistance from the electronics. First, we tried to introduce this philosophy to help Jack. And second, because we believe it’s the correct approach and now we have a rider [Binder] that realised this and then we transferred this philosophy to our other riders.

What were the big positives of the 2023 RC16?

It allowed us to use the grip in a better way, which also helped us to improve our qualifying positions. In general it was rear grip, but not only on corner exit, also in entry.

In 2022 we had the impression that we could not use the extra grip we got from a new tyre, which is why we struggled in qualifying and over a single lap, so this was our target: to sacrifice something in ultimate grip to make the extra grip you get from the tyre more useable. [This fits with my recent blog about Wayne Rainey and Kevin Schwantz going faster with less grip in 1991.]

How do you sacrifice ultimate grip to make the tyre more useable?

I cannot tell you this, sorry! It’s not one answer, it’s complex. It was a lot of work on many aspects.

Now you’re pretty much there with the Ducati, but you obviously need another step, so what’s your focus for 2024?

Yes, I’d say we are kind of there. We are now playing the same game as the others.

“For the riders it’s clear that the frame mainly improves grip, in entry and on exit”

Before last season you sometimes saw the others fall out of their working windows at one track where we jumped into our working window and we had a brilliant weekend. But you cannot rely on this, so now we are more similar to our competitors, in the character of when our bike is working and how it’s working. Now it’s all details to raise that level, so you see that we don’t have these brilliant and dominating weekends anymore, but of course we want both.

You’ve now entered a new world with a carbon-fibre frame, so where does the frame make a difference – in drive grip or on the edge of the tyre?

You have to separate it a bit. One factor is the job of introducing a certain technology and materials.

The other is in the detail of this particular frame. Of course when you introduce this new thing you get both. Our first carbon frame was already the best frame we’ve found so far in this new generation [since KTM moved way from its original steel trellis design at the end of 2019] and for the riders it’s clear that the frame mainly improves grip, in entry and on exit.

Is that down to more torsional stiffness?

You cannot put it down to one number like that. Of course you have the static numbers, but also you have the dynamic behaviour, the difference in weight and the changes in weight distribution because of this.

I heard the carbon frame is two kilos lighter.

It’s quite a step lighter.

I can see how the frame helps out of corners, because it allows the suspension to do a better job once the rider picks up the bike, so is it the same on the way into corners?

Yes, exactly. It’s rear contact [tyre-to-track] and when you improve rear grip on entry the rider gets more help from the rear tyre, so he can rely more on it. He can use the rear brake more if he needs to, to rebalance the bike and so on.

To keep better contact with the road…

In the end it’s the tyre that has to work better. How you achieve that isn’t so straightforward with these tyres, but yes, we are now working the tyre in a way that we can use it better in corner entry.

Are you also trying to get more lateral flex for more mid-corner grip?

It’s not so easy to separate those phases. If you change something in corner entry it gives the rider the tools to use a different line and also to use the bike in a different way, also in mid-corner. So if you change something in corner entry, for sure you will have an effect mid-corner, even if the bike, in theory, should behave the same there.

What about crash damage – presumably this isn’t so easy to check with a carbon-fibre chassis?

Of course, it’s a big challenge.

Do you have some kind of apparatus to check crashed frames at the track?

This technology is a big challenge and to jump into this was a brave but very conscious decision. We are convinced that sooner or later everyone will end up with this technology. We have the technology and we have the partners, so we decided we wanted to lead this evolution.

This means we also have to address the crash-damage issue, so to have the possibility to check frames and to get the experience – how to check the frames and what to check – the sooner you start, the sooner you will have an advantage. This is why we took this decision.

[I’ve since learned that some motor sport companies use stress indicators in their carbon-fibre components, which change colour according to the severity of impact, so engineers can see if the component is too damaged or not.]

In the earlier part of last season your riders complained about corner-exit wheelspin – that’s mostly gone now, because you’re getting better grip from the carbon frame?

First of all you have to separate how the bike feels on a certain track with certain tyres over race distance and the other thing is how this compares to your competitors.

Last season we faced many races where our riders had to manage the rear tyre during the race and they didn’t have the grip they wished for, so maybe it felt horrible to them. But when our guys got a good result they didn’t even mention grip, because they saw the top guys having the same grip problems they had.

When riders are struggling, for whatever reason, this negative impression that they don’t have the grip they need is the dominant thing they feel and they suffer from it.

I wouldn’t say that the spin isn’t there anymore, but now it’s more in the hand of the riders to manage. It’s clear that when you spin too much you don’t gain performance, so the riders must understand how to manage that and they have understood that.

Your riders Jack and Brad tell us that they now take longer lines through the corners, whereas the RC16 used to be a v-line bike. Once again, this sounds like you’ve followed Ducati, by going longer to get better performance from the tyres.

Yes, it always depends on the competition. Some years ago the reference was Marc Márquez with the Honda and the whole championship went that way. Now the reference is Pecco Bagnaia with the Ducati and everyone is looking at that combination and knows this is the one to beat, so of course you have to adapt your style to do that and it’s something we had clearly observed: previously they were quite opposite [to us] in terms of their approach.

Jack and Brad get sideways on the brakes to use the rear tyre to stop the bike and unload the front tyre. Is that something for which you set the bike up for, or is it just something they do?

Of course you need something different from the bike, depending on how you enter the corner. I think this sideways thing that our bike needs to unload the front is something that’s been in our DNA for a long time, already when Pol Espargaró joined the project in 2017 and when Brad joined in 2020.

If you remember Brad’s first races [Binder won third time out in MotoGP, at the 2020 Czech GP], then we went a little away from there because the 2021 front tyre allocation didn’t need the sideways thing to give us performance.

Now it looks like we have come a bit back to that – we have found ways to give the riders this control they need for the rear tyre. Sideways doesn’t always make you faster, but when you have a rider that has the skill and the riding style to do this and you hit the right setting for the tyres you have, the conditions and so on, then, yes, it can make you faster in some areas.

At Mugello last year your aero upgrade featured diffusers at the bottom of the fairing [like Ducati’s], then you switched back and forth between that fairing and the older fairing, why?

I understand that the diffusers are what people really notice when they look at that fairing, but it’s really just one feature of a whole concept. Basically the second generation we introduced at Mugello has a better compromise of drag and downforce, but in terms of stopping and rideability the old fairing has some advantages. So we have to decide from track to track and consciously go for one concept or another.