MotoGP Court Of Appeal Rules Ducati's Swing Arm Aero Spoiler Legal, Confirms Dovizioso As Qatar Race Winner

The MotoGP Court of Appeal has ruled that Ducati's aero spoiler, attached to the bottom of the swing arm of the three Desmosedici GP19s and used in the opening MotoGP race at Qatar, is legal. The decision of the court means that the race result stands, and that Ducati can continue to use the spoiler going forward.

Ducati's aerodynamic spoiler, ruled legal by the FIM

The decision comes after the Court of Appeal heard a protest, submitted by Aprilia, Honda, KTM, and Suzuki against the ruling by MotoGP Technical Director that Ducati's device was legal. After the race, the four factories protested first to the FIM Stewards, who rejected the protest, and then to the FIM Appeal Stewards, who ruled that they needed technical information to judge the merits of the case, and so referred the protest to the MotoGP Court of Appeal.

Last Friday, the Court of Appeal sat in Mies, Switzerland, the offices of the FIM, and heard submissions from Ducati, and from the other four factories who submitted the appeal. Ducati had Fabiano Sterlacchini present alongside Gigi Dall'Igna, while Suzuki and Aprilia had brought Filippo Petrucci, a Ferrari engineer who had worked with Michael Schumacher in F1 previously, to help present their objections. 

The case revolved around the function of the spoiler fitted to the bottom of the Ducati's swing arm. Ducati claim that it helps to cool the rear tire. The other four factories, Aprilia foremost among them, point to the fact that the spoiler has three horizontal vanes, which must, they claim, create some kind of downforce. 

New guidelines

The case was only made possible because Ducati and Aprilia presented swing arm-mounted spoilers to MotoGP Technical Director Danny Aldridge to ask whether they would be legal. As part of the additional technical guidelines, Aldridge ruled that devices could be attached to the bottom of the swing arm, if they were solely to be used for deflecting water or debris from the rear tire, for the purpose of cooling the rear tire, and "their purpose is not to generate aerodynamic forces with respect to the ground".

Ducati managed to convince Aldridge that their spoiler was used for cooling the rear tire. No doubt the fact that the spoiler is only fitted together with the front wheel covers helped persuade him of their case. Aprilia, who had asked to use a device which they were using to generate downforce, and which Aldridge had rejected, decided to protest Ducati's use of the spoiler.

The MotoGP Court of Appeal has now found in favor of Ducati, ruling that the use of the spoiler was legal, and that they can use the spoiler in future races. This also means that the result of the MotoGP season opener at Qatar stands, and Andrea Dovizioso keeps his race win, and his lead in the MotoGP championship. 

This is not the final step in the process, however. Aprilia, Honda, KTM, and Suzuki now have five days to protest against this decision, and appeal it to the Court of Arbitration for Sport, the CAS. I understand that as yet, no decision on an appeal has been taken, in large part because the FIM only released the decision, and not the reasoning behind the decision. Without knowing what persuaded the three judges who heard the case, it is hard for the four factories to decide whether an appeal to the CAS would stand a chance.

Lessons for the future

Two things seem clear from this decision of the MotoGP Court of Appeal. The first is that the MotoGP regulations on aerodynamics are badly in need of clarification. As an example, the technical guidelines issued by Danny Aldridge speak of "attachments to the rear swing arm". As some people have pointed out, this is easily circumvented by integrating the spoiler into the shape of the swing arm. These issues will not be solved by issuing further guidelines; it needs a full overhaul of the rules.

Which raises a larger problem. The MSMA, the manufacturers association, are responsible for the technical rules in MotoGP in the first instance. Any proposal for a change to the technical regulations must come from them, with Dorna and the FIM only able to put forward proposals related to safety. But as I wrote last week, keeping the MSMA together is no longer easy with six factories involved. There are growing signs of splits inside the MSMA, and open recrimination between some of the principals. Ducati Corse boss Gigi Dall'Igna reportedly said in Qatar that he had been faced with "laypeople" on the other side of the table. KTM's Mike Leitner retorted that "nobody could believe that the race departments of Aprilia, Suzuki, Honda, and KTM only employ laypeople".

Ducati, and especially Gigi Dall'Igna, have made no secret of their desire to continue to explore the possibilities offered by aerodynamics. The other factories are much less keen, fearing the cost an aerodynamics war might unleash. The chances of  the six factories involved in MotoGP being able to produce a unanimous proposal on aerodynamics seem to be close to zero.

The FIM could still adopt a proposal not presented unanimously, of course. The rule book only obliges the Grand Prix Commission to accept technical proposals put forward by the MSMA if all MSMA members agree unanimously. The other five MSMA members could put forward a proposal which Ducati disagrees with, and Dorna, IRTA, and the FIM could consider it on its merits. Given the aversion inside Dorna and IRTA against aerodynamics, such a proposal should pass the GPC with relatively little resistance. 

But that is in the future. First, we must wait and see if any of the four manufacturers decide to appeal the decision of the MotoGP Court of Appeal to the CAS.

The FIM press release from the Court of Appeal appears below:

MotoGP Court of Appeal hands down decision
Case against Ducati aerodynamic devices

VisitQatar Grand Prix – Doha (QAT), 10 March

During the MotoGP race at the season opener in Qatar on 10 March 2019, technical protests concerning the use of a device on the Ducati machine were lodged with the FIM MotoGP Stewards by Team Suzuki Ecstar against #43 Jack Miller (Ducati), by Repsol Honda Team against #4 Andrea Dovizioso (Ducati), and by Red Bull KTM Factory Team and Aprilia Racing Team Gresini against #9 Danilo Petrucci (Ducati).

The protesting teams considered that the device was primarily an aerodynamic device and therefore not compliant with the MotoGP technical regulations. After a hearing, the four protests were rejected.

The same four teams then lodged appeals against the MotoGP Stewards’ decision to the MotoGP Appeal Stewards and a further hearing was conducted. The MotoGP Appeal Stewards determined that further technical evaluation was required and that this was not possible under the circumstances. They therefore decided to refer the matter to the MotoGP Court of Appeal in accordance with Art. of the applicable Regulations.

Following a hearing in Mies on Friday 22 March, the MotoGP Court of Appeal handed down its decision today 26 March and the parties (the four appellants, Ducati and the FIM) have been duly notified.

On these grounds, the MotoGP Court of Appeal rules that:

  • The appeals filed by Team Aprilia, Team Suzuki, Team Honda and Team KTM are admissible.
  • The provisional race results are confirmed and are declared as final.
  • The request to declare the Device illegal and ban its use in future races is rejected.

An appeal against this decision may be lodged before the Court of Arbitration of Sport (CAS) in Lausanne Switzerland within 5 days pursuant to Article 3.9 of the 2019 FIM World Championship Grand Prix Regulations.


Back to top


I say this from a neutral perspective but I am really surprised by this ruling. Thought this would have been a slam dunk for the protesting factories. Anybody else see the leering genie madly cackling at its new freedom?

... it seems the rules were so badly written that they were unenforcable.  Probably revolving around the "intention" or "function" or whatever of the spoiler being for cooling, and any downforce generated was an unintended side effect.  Easy to side step.  I have no legal idea whatsoever but from what I've read from David previously & my understanding of the letter of the rules, I figured it was a slam dunk for Ducati.  Gigi said so and he was spot on. 

I was actually surprised the other factories were taking it this far but as pointed out, this was likely so that the whole aero section of the rule book can be revisited.  In reality, the position we are at now with wings is pretty ridiculous in the light of the wings getting "banned" a couple of years back.  The appendages on the bikes now are just as prominent - if not more so - than before the 'ban'.  I liked the sound of the original rules... anything the technical director didn't like the look of could be banned.  If it had of been enforced it might have worked, but increasingly aero fairings were continually proposed and approved.  The only one who had a crack at making a downforce fairing to my interpretation of the original rules was Aprilia with their 'duct' fairing.  It clearly didn't work very well as it continued to adorn Lowes bike all year!

Obviously this year is going to see some wild solutions, but the FIM and Dorna need to stick a fork in this one at the end of the season. A very open ended ban on any devices that 'could' be used to generate downforce and hacksaw rules to enforce them.


We know from F1 and Sportscars that aero is a bottomless money pit. The idea that F1 was close racing back in the day is a bit of a myth, even in the 60s and 70s winning margins were tens of seconds and laps, but in the modern era teams are spending well over $100million to come last by two laps and $500million plus to see the podium regularly. Moto GP can't sustain that, VW Group (through Ducati) and Honda might, but nobody else has that cash available, not even KTM and Red Bull. I expect aero to become a safety risk too, aero dependant racing cars have some monster crashes when that airflow is disturbed, a downforce reliant GP bike letting go would be very messy indeed.

As someone who's pulling for Petrucci to get on the top step of the podium and who feels this could be his best and only season to do it, I'm happy with the decision.

Surprising result and all of that, but pat on the back to team Ducati.   They came this season to win and the rule of winning is to understand the rulebook in and out and develop as far as you can within the written guidelines. Gigi and team crew lread the rulebook, looking for whitespace and they found it.  It's gonna pay off this season.  

Next season, swingarm aero will be banned and Dovi will have winglets on the shoulders of is Alpinestars leathers.  

So...who else shows up with something similar at the remote patch of tire-punishing hell that is Termas del rio Hondo?

Answer? The ones who have been paying attention (instead of launching pacifiers over the edge of their prams). Yamaha was conspicuously absent from the pitch fork and torches club party after the opening round, as they already have something similar with their rain guard. In any event, as Mr. Emmet informs us, this is a really tricky bit of turf.

Gigi had a very off-the-cuff interview with the Italian GP_One site where, with his blood up a bit, he finally revealed a few things.

The "vanes" between the endplates (which make it look like a "scoop", though it is decidedly not that) are there to maximize the velocity of the airstream directed at the rear tire. This is their primary function, and a critical one. To effectively cool the rear tire the cooling air velocity needs to be as high as possible, to essentially blast away the super-heated boundary layer of air that is rotating with Michelin's best effort. Of course, if you are going to accelerate airflow, you will also impart a pressure change as well. So do you want that pressure change, slight though it may be, to help you or hurt you? Easy answer. And for those of us that wanted to vote "neither, it should be neutral", sorry, that item is not on our menu. Even if the "neither" option could be found, it only exists at one speed and lean angle, which makes it about as common as unicorns that play the tuba...while roller skating. And every bit as useful.

Every surface in contact with the airflow has an aerodynamic effect. And as such it can be shaped directly (in the case of our inverted wings) or subtly (in the case of everything else) to aid or obstruct our quest for the optimum tire contact patch pressure. If we do not allow that, then we need to have everyone line up without front fenders, because on a dry track they have no other purpose than to function as a very important aerodynamic aid. And here is where we follow the rabbit down the hole for a bit; from the standpoint of the tire contact patch it does not matter if the aero device removes 15 Kg of lift (like a well shaped front fender) or adds 15 kg of downforce (like a pair of canards mounted on the front axle with no fender would do). In the end what the Michelin sees is +15 Kg, and could give a tinker's dam how it got there. As a designer, having the rules simply say "cannot create downforce" would make my evil and devious heart sing with joy as it contemplated all the places I could reduce lift with complete impunity. You may as well admonish a thief that he is not allowed to steal more than he can carry.

As David also pointed out, this can be a bit overwhelming for the MSMA and Technical Director unless they are given more help. Greater authority, in and of itself, has limited value without the technical staff to sort all this out. King Canute would not have succeeded if only he had been elevated to Emperor Canute. King or Emperor, they would both go home with damp trousers. If MotoGP wants to play with model rockets, as opposed to paper airplanes, they need to add some more brains to the payroll (I think the brains they have now are big enough, but there are not enough of them).

I hate to even suggest this, but perhaps Michelin could also provide some guidance as to maximum tire pressures under straight-line conditions in a certain speed range (say 200-300 Kph) that are not to be exceeded. Eliminate the slow gear acceleration and all braking from the analysis. Just a basic "run the bloody thing at 250 Kph along a straight during testing and show us your tire pressure data".

As long as you are under a certain pressure away. Or some clever lad needs to sort out how to get the toothpaste back in the tube. Honestly, that last one has always stumped me. Cheers.

I would love to see more photos that show what is inbetween the side plates.

Probably too simplistic but it looks like it deflects air upwards onto the tyre and starting with a sloped hand stuck out a car window any sloped blade that I have seen that deflects air upwards creates down force to some degree.

Don't worry, Danny will believe you.  Just don't commit the sin of being honest about the purpose, as Aprillia learned at their cost.


Assuming that air is flowing in a laminar way from the front to the back of the bike (big assumption I know), then the Ducati scoop is only collecting the air which is already going to hit the rear tyre.  Perhaps making it hit the tyre at a more perpendicular angle is allowing to to have more of a cooling effect, but, if it was truly and only for cooling, then wouldn't it make more sense to be collecting air with a wider scoop and directing it towards the tyre?

Thinking back to comments from Petrucci, I’m sure Gigi has a few choice words for him after he stated that the device is NOT for cooling the tire. 

This is from asphaltandrubber but I’m sure it was quoted elsewhere.  Danilo Petrucci, who told us on Friday, “We saw on television that it was for cooling down the rear tire but it is not like this. But I can’t tell you what it is for, because Gigi will get angry.”

Loose lips...

So, the important issue here is what Ducati say it does rather than what it may be demonstrated to do. OK, great, that's a sound basis for a set of rules.

Not sure why people are blaming Ducati for their ability to read the rulebook carefully, and find gaps to exploit to gain advantage wherever possible.  Seems like Gigi just embarrased his counterparts for failing to see the opportunity first.

Your point is valid if you assume that everybody else is equally dishonest.  Gigi did have to lie to get his "cooling device" through.

Unless you are the only person (that I have heard of) who really believes that they needed to cool tires at a race where the biggest problem was maintaining sufficient tyre temperature?

Aldridge's vacillations in enforcing aerodynamic rules has opened Pandora's box. The MotoGP Court of Appeal had the chance to close it but instead has begun the next era of aero-dominated MotoGP, following the example of F1, which will be so costly that most of the teams will leave MotoGP and we will once again have a super expensive manufacturers cage-fight between two or three riders. Well done FIM!

it is not the court’s job to determine the direction of the sport, it is their job to determine legality based on the rules as written.

As the rules currently stand the device attached to the swingarm is in the wake and therefore not part of the Aero Body, so it is open slather. Well read, Gigi.

Your title here reveals a bit eh? I think they declared the tire cooling device as not breaking the stated rule. I don't find this too big a deal frankly. Glad we aren't still in the unseen electronics war. Or the "overnight race day specials for one wealthy overdog" tire era. Rules will adjust. And aero tech like this is much easier to mimic that nearly ANY other, skipping some cost.

Supporting Ducati right now. Prefer less aero, but accepting what is generally. Enjoying the Red buggers socking it to Honda.

This MSMA at odds with each other may be a healthier one relative to the old "Honda declares rules supporting their superiority, unchallenged/enabled by Yamaha that may also benefit." That was mob boss shite.

Full gas, Dovi and Bologna

Is well known in moral philosophy, by which only that which is intended (the cooling of the tyre) may be culpable (Innocent, then) and any second effect (vide downforce) may not be subject of any moral judgement (so, innocent, as no trial). It's Kant rather than Bentham, who was into consequences (downforce as well) rather than intentions.

Kant, the wonderful trancendentalist, cast his awareness far, wide and deep. Bentham, Mill, et al, the simple cheese eating chumps, don't. Not just intention, but method. Bentham-->bedlam of "ME!" and Kant-->want for "WE."

Over time for me Honda seem the teleological buttholes, Duc the deontological innovators.

Bentham looked far and wide for consequences, Kant simply at intention? The double-effect business is deeply morally corrupt, imho, and should be no safe home for the devious: innovation is superb, but I'd rather a real-world consequentialism than mask my intentions.

I hear you Pops. We have some F1 games going on which sucks. Rulebook pushing is as old as rules. I don't want to cheat, but I DO want to do the thing that becomes legal. I had a technically illegal airbox mod for Supersport. Everyone did it, it was just a damn good setup. Then one single racer filed a complaint against a rider ahead of him in standings. Everyone was shocked. I think he was the a-hole.

Get a kick out of what Honda is doing right now w this...

Anyhoo, nice to see another ethics geek here. Kant goes DEEP. W me too, we go way back.

Cheers mate, enjoy Argentina!