‘MotoGP would be a completely different game without downforce aero’


Downforce aerodynamics has transformed MotoGP, demanding more extreme engines, different chassis geometry, even different chassis stiffness. KTM RC16 project leader Sebastian Risse explains all…

Side view of Jack Miller at 2023 Le Mans MotoGP round

Jack Miller exits the final turn at Le Mans. The RC16 has all the latest aero gear: looped upper front wings, lower front wings, slab-sided ground-effect fairing, diffusers, swingarm wing and seat wing

KTM/Polarity Photo

KTM is MotoGP’s big improver of 2023, going from mostly struggling to get inside the top five to leading races and battling for victories with its latest RC16.

Improvements always come from a combination of factors, but KTM has particularly increased its work on aerodynamics. KTM’s MotoGP aerodynamicists now work with those from Red Bull Advanced Technologies, the engineering branch of the Red Bull Formula 1 team – the reigning world champions – because F1 has a much longer history of working on aero than MotoGP.

For example, last year at Jerez, Brad Binder told me he was losing the front every lap through the scary-fast right-hander before the final hairpin, because at that speed there was so much downforce it was taking the forks to the bottom of their stroke, which transferred too much load to the front tyre.

KTM has also profited from hiring more Ducati engineers, most notably Alby Giribuola, former crew chief to Andrea Dovizioso and Enea Bastianini, who is now the factory’s chief performance engineer.

Although this year’s RC16 doesn’t look dramatically different from last year’s, it is, with upgraded chassis, engine with revised firing configuration, rewritten electronics, cable clutch (for better starts), ground-effect fairing and so on.

At COTA, where the back straight is a real-life dyno, because bikes accelerate all the way from first gear to sixth, the RC16 was the fastest of them at 218.7mph (352.2km/h), which means its engine, electronics, ride-height device and aerodynamics complement each other very well.

KTM rear wing

The second iteration of the seat wing, first raced at Le Mans, features a Gurney flap on its trailing edge to increase downforce for more corner-exit grip, without increasing drag too much. Note the amount of Dorna comms gear on the seat. The rear-facing camera really interferes with the aero, but riders don’t have to use them at every race


The 2023 RC16 fairing blends aero technology introduced by Ducati and Aprilia in the last couple of seasons. Its Aprilia-style fairing lower has bulging, slab sides, which create a large area parallel to the ground at high lean angles. This, combined with Ducati-style diffusers, accelerates airflow beneath the bike, creating an area of low pressure, which pushes the bike into the ground, improving grip and therefore turning.

The strange thing about all of this is that KTM doesn’t actually like downforce aerodynamics – because its engineers believe the ‘dirty air’ created by aero makes overtaking more difficult, which spoils the racing show – but has no option but to invest heavily in this area of development.


Mat Oxley: You started working with Red Bull Advanced Technologies last year, so was aerodynamics top of your list for 2023?

Sebastian Risse: One thing is how big aerodynamics is on your list of things to do, the other thing is what resources you have. One key point for us has been to increase those resources. You need the people to design parts, to make them, to test them in CFD [computational fluid dynamics, which analyse and solves airflow issues], in the wind tunnel and on the track, then analyse all of that.

What proportion of CFD and wind-tunnel work do you do before trying new aero parts on the track?

Normally the first iteration is CFD, then you use the wind tunnel to validate that. And if something doesn’t match, you put it back into the loop and this is what makes a new part better in the end, because when you learn that something isn’t matching between CFD and reality, you either go back into the CFD or you take it the next step to the track.

KTM front comparison 2022 vs 2023

2022 and 2023 RC16 aero – lots of subtle changes that make not-so-subtle differences. Note that last year’s Gurney flaps on the trailing edges of the lower big wings have gone, possibly because they gave too much downforce


Is it all a bit of a black art, because it’s such a new world in bikes?

It’s not a completely new area of working, but now [with downforce aero] the targets are quite complex, so you need to know exactly what you’re looking for and this is where we are constantly growing our knowledge, because we now have the resources to learn quicker, react quicker and learn every day.

Do you work with actual bikes or scale models in the wind tunnel?

We work with full-size motorcycles.

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And in which attitudes do you test the bike? Presumably, you need to go from upright to maximum lean and pitching forward and back…

You can do many things with the bike in the wind tunnel, but it’s quite difficult to have accurate measurements for these complex load cases [the distribution of forces] and also quite difficult to analyse.

So it’s much easier to simulate all these different load cases in CFD. Then the wind tunnel is more about validating the CFD. It all depends which areas you’re interested in, or where you’ve found some mismatches; then you try to replicate that in the wind tunnel and validate things.

Do you use your MotoGP riders in the wind tunnel or mannequins of your riders?

We work with riders.

Presumably you can’t use Brad Binder, Jack Miller and your GASGAS riders all the time, so do you have doppelgängers?

Yes, we do, but when we bring our riders to the wind tunnel it’s more about individual set-up, with their leathers and other riding equipment, plus things like stability, which can be quite difficult to measure but are very easy for the riders to understand.

KTM lower fairing

KTM’s latest slab-sided lower fairing and diffusers must be low to the ground to create so-called ground effect, which creates more grip. Look carefully and you’ll see that at Jerez the diffusers got too low!


This year’s RC16 fairing is fitted with diffusers, which are smaller than Ducati’s, so much effect do they have?

I don’t see them as separate components or add-ons. They are part of the concept of how we’ve shaped the fairing and they are big enough to control the airflow according to the fairing shape.

To give you an example, we also had some fairing options which created the same effect without the diffusers. The thing is to get the flow you want and how you do that is up to the creativity of the engineers.

Do your diffusers create a low-pressure area?

Not directly, no.

But the slab-side fairing does create some ground effect?

When you want to use ground effect you need your aerodynamic body close to the ground and you need to control the airflow around it. That’s what the diffusers do – they clean up the flow, make sure it goes where we want it and they make the flow stable.

Last year you struggled with turning, forcing riders to use longer, more rounded lines, so has this new aero helped in this area?

In the end it’s the package of the whole fairing, but, yes, I do think we’ve made a step with the fairing.

KTM team celebrate Brad Binder sprint race win in Argentina 2023

Risse (wearing glasses, immediately in front of Binder) and the rest of the KTM crew celebrate Binder’s sprint race victory in Argentina


You work in Toyota’s wind tunnel in Cologne, right?

This I cannot say.

All this aero – downforce and ground effect – must increase mid-corner forces, so does it affect how stiff you make the RC16’s chassis?

During the last few years aero development has changed a lot how the rider uses the bike, how we set up the bike and what kind of forces we have at what moment. So globally, I’d say, yes, but talking particularly about mid-corner, I don’t think so.

From the archive

What effect does downforce aero have on tyre life?

It depends how you work the tyres generally with the bike. Looking back at last year we had big problems overloading the front tyre. I wouldn’t say we had too much downforce and I also wouldn’t say we have less now, but we’ve found a way to make it more useable. And it’s clear that you can affect tyre life with the aero, in a positive or negative way.

What about geometry changes? For example, Yamaha engineers say they’ve used the effect of downforce aero to change the M1’s geometry for better drive out of corners.

Yes, exactly. In the end, bike balance is the cumulation of the way the rider rides, the set-up balance and the aero balance. Unfortunately the aero balance depends on the speed, so to find a compromise that fits every corner is very difficult. But for sure if you took off the wings or fitted a fairing from six years ago, the balance of our current bike would be completely out of the window.

So downforce aero has changed everything – braking, turning, accelerating – so MotoGP is a new game…

Absolutely, yes. I’d even take it one step further. It’s not just on the set-up side, it’s even how we are developing the engine. I think MotoGP would be a completely different game without this downforce aero.

Side view of Brad Binder in 2023 Argentine MotoGP round

Binder tucked in down the back straight in Argentina. Note that he was down to use the seat camera in this race and it’s easy to see how it plays havoc with the efficiency of the seat wing

KTN/Polarity Photo

Does it change engine development because you can find more corner-exit drive with the downforce and ride-height devices?

Exactly. Nobody could use all this power if all of that wasn’t there. Without all the aero a more rideable engine would work much better than a high-performance engine.

So you’re going more and more extreme with the power?

You have to, because now you need power to waste! [Because downforce equals drag.]

In the early years of modern MotoGP aero development it was all about front downforce, but now most of the bikes have rear aero too, so it must be tricky to find the right balance?

The danger when you do all of this is that the bike can feel like it’s on rails, so it’s a very difficult compromise you have to make. But for sure the target is to keep the balance more neutral and still have the bike in your hands.

Will we see more and bigger rear wings?

Of course we have to make a compromise with the Dorna devices, like the rear camera, so it’s quite a difficult area to work in, also because it’s affected so much by the airflow around the rider, which is very uncontrolled and not a reproducible thing, because the rider is always moving around.

It’s better than nothing to work in this area. Already three years ago we had some wing shapes integrated into the rear, but to get it really under control, so the rider can really use the benefit, was not so easy, so I’m not sure how radical you can go in this area.

Jack Miller leads Brad Binder and Pecco Bagnaia in 2023 MotoGP Spanish GP

Miller and Binder fight with Ducati’s Pecco Bagnaia at Jerez. Bagnaia won the battle but the RC16s looked more manoeuvrable than the Desmosedici

KTM/Polarity Photo

The rider must make a huge difference to the aero when he hangs off and puts his knees and elbows on the ground?

For sure. When the rider hangs off the airflow is a completely different story. You block one side, so there’s no flow

What does that do?

It creates some asymmetrical aerodynamic forces, so the target is to use that in your favour.

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Will all of this have any benefit for everyday motorcyclists?

Normal, legal speeds on the roads are too low, so if you’re talking about aero for road bikes it’s mainly about comfort and stability.

We have been working on aero with our production bikes for long time, and now we have more and more resources in this area, so we can feed more information back.

KTM has never liked MotoGP’s push towards downforce aero, so it must be a bit weird working on something you don’t want.

Here, you have to think in two different directions. One, do we believe it’s good for the sport? No, clearly not. The other is, if there’s any area in the rule book which you can exploit and gain an advantage from, then you have to use it. This is racing. So we aren’t hesitant to do it and we put in our full effort and we are also excited about what we are doing. But this is because it’s something that’s allowed, even though we believe it’s not right for the sport.

Will things change? Most manufacturers want a reduction in aero and many people believe it’s spoiling the racing…

Yes, absolutely, and safety also plays into this a lot. The performance of the bikes is getting more and more – for example how much more engine power is coming from working with downforce aero.