KTM's Sebastian Risse: On 3D Printing, New Chassis, Dealing With Tires, And The Frustration Of Ride Height Devices

KTM has seen not one, but two remarkable turnarounds in recent years. First, there was the huge step in performance between 2019 and 2020, after the Austrian factory introduced a radically different chassis, switching from circular section tubes to oval section for their steel chassis. That saw KTM go from fighting for the spots just outside the top five to winning three races and consistently battling for the podium.

So it came as a surprise at the opening races of the 2021 season that the KTM riders were suddenly struggling again, Miguel Oliveira finishing tenth in the first race at Qatar, teammate Brad Binder ending up eighth at the second race at Losail. KTM found themselves heavily penalized by a change in the front tire allocation, with a switch to more asymmetric tires.

That required a review of their current development direction, and after another revision to the chassis, and a change of fuel supplier, Miguel Oliveira was back on the podium at Mugello. The improvements were confirmed when the Portuguese rider won the next race at Barcelona.

Before the race at Assen, I spoke to Sebastian Risse, as Technical Coordinator, the man in charge of KTM's MotoGP project. In the interview, Risse explained how they had changed the KTM RC16 to achieve these remarkable turnarounds. In our extended conversation, we covered 3D printing, chassis stiffness, building a more versatile MotoGP bike, and dealing with changing tire allocations. Risse also explained his dislike of the current round of holeshot and ride-height devices, and gave his views on aerodynamics. A fascinating insight into the process of developing a MotoGP machine.

Q: Obviously, you made a big step from 2019 to 2020. Can you talk about that change? What do you think was the big change from 2019 to 2020?

SR: It was a different bike. It was really quite radically different and the intention to 2020 was to make it more rideable, easier to ride and more versatile to be ridden with different riding styles. Because at that time we had Pol [Espargaro], who was very fast and very special in the way he’s riding, very aggressive. Other riders struggled to do it like him, or generally to be fast on our bike. So, there was a lot of effort on that. I think it really paid off because finally then in 2020 we had different riders with quite different riding styles that still came to a very similar result in the end, in terms of lap time and success.

Q: Could you tell me anything about how you changed the bike? Did you change the weight distribution, make it a little bit softer, a little bit more flexible, or a little bit less aggressive in terms of geometry?

SR: I would say the main things were making it lighter, which anyway helps no matter which riding style, and it’s mechanically more efficient in all terms. I think where the performance and the rideability came from was mainly the stiffness, yes, in different areas of the bike.

Q: Part of that was also the change in the chassis that was really obvious that it was no longer tubes. It was a sort of an oval section. Have you always been building that section with 3D printing? Do you also produce them manually?

SR: To be honest, this concept of not circular tube cross sections is not new. KTM has used it in off-road for many years in different contexts. We also had a Moto3 prototype one which was following this. The idea behind it is obvious. It’s a different combination of the different stiffnesses that you can create, and in the end then a different flexing mode of the bike. You can achieve that with tubes, classic tubes, but also with [3D] printed parts.

The nice thing about 3D printing is mainly that you’re even more flexible, changing the wall thickness, the shape really to your requirements, especially when it’s quite a complex area of the bike where you have different mounting points, different tubes coming from different directions have to join, things like this. That’s where it’s really powerful.

Q: Is this purely a technology which is going to be used for prototypes, or could it be used for production bikes or not at all?

SR: I think it is the future, more and more. Already for example in airplanes it’s used as a production process really for the final series. I think that will come in many industries, also in bikes.

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Comments

... comments about the shape-shifter/lowering/start devices. I wish they'd go back to the hell they came from, but with some street bikes already having similar versions of electronic automatic devices, if Moto GP has to have them I don't see the point in banning the electronics from taking care of it on the race bikes.

When the bikes all hunker down on the start like vipers coiling to strike it looks like the future! I love it!

Insane 0-100mph times are great for the technological prestige of the series too.

I wonder where we would be if Dorna hadn't stagnated the electronics regs in 2016, I remember HRC casting shade on the unified software to the effect of "what is this preschool shit?!"

Dorna were abolutely right to break the hegemony of HRC and YRT, the racing has been vastly improved I think and we're closer to parity through many different engineering approaches but we learned so much about vehicle dynamics from '08 to '15. Imagine how insanely clever the logic and control routines could be now with the rise of advanced machine learning and AI in the intervening period.

I had to go on a long trawl to find this but it's from a deep dive on the last generation RC212V 800:

https://web.archive.org/web/20150107034653/http://world.honda.com/RC-V/R...

Honda were bringing their full weight to bear on a brilliantly complex problem 10 years ago and look at how good road bike electronic control systems are now. I really feel that race spec coding is just as trick as hand welded titanium headers and beautifully optimised milled aluminium trinkets, it's such a shame it's super secret squirrel proprietary IP, I would love to know the ins and outs of the development philosophies and techniques used at the very tip of the motorsport spear.
I feel like the BSB thinking: "derp, elecktrickery is ruining racing, it's just playstation now" has been a major setback to performance for all of us.

As someone who has done my share of embedded programming, and someone who paid attention when Toyota were being sued for runaway throttles. I'd bet that this trick software package was nothing of the sort. It is probably a mass of spaghetti code, with layer upon layer of fixes and patches to the point where no one (maybe one nerd) fully understands it. Is so critical, it can't be substantially modded for fear of breaking it, and has no requirements or test plan and can't be re-written. Under the hood, these systems are the digital equivalent of the sausage factory.