MotoGP 2023: the real aero war starts now


MotoGP’s first pre-season tests at Sepang had every factory using ground-effect aerodynamics for the first time. But Ducati’s aero is still the best – good enough to put Luca Marini on top aboard a GP22

Luca Marini on Ducati in 2023 MotoGP test

Luca Marini, equipped with Ducati’s standard ground-effect fairing, was fastest at Sepang. Note the F1-inspired diffusers close to the track


Serious MotoGP downforce aerodynamics first appeared in 2016, to reduce wheelies and thereby increase acceleration, by increasing load on the front end.

“If you look at the data you can easily understand that wheelies are one of the main problems in MotoGP, so if you want to improve your lap times you have to do something in order to reduce wheelies,” Ducati engineer Gigi Dall’Igna told me last year. “At some tracks like Jerez the horsepower of the engine means nothing, but with wings you can start to use the power.”

Honda & Yamaha didn’t want an aero war but have accepted this is the way MotoGP is going

Over the next few years many people talked about MotoGP’s new aero war, but, looking back now, that was the phoney war, because the real aero war starts now, because all five factories used Formula 1-inspired ground-effect aerodynamics for the first time at Sepang.

Ducati, of course, led the way two years ago, with a new ground-effect diffuser fairing that increased grip for better turning. Aprilia followed midway through last season with a non-diffuser ground-effect fairing, then Honda added diffusers to its RC213V for the last few races.

Now KTM and Yamaha have joined in, unveiling their first ground-effect diffuser fairings at Sepang.

How does this technology, pioneered 50 years ago in F1, work? It’s simple: you design your bodywork to accelerate the airflow between the fairing and the ground at full lean. This creates a low-pressure area, so the atmospheric pressure pushes the motorcycle into the asphalt, increasing grip. This is called aerodynamic grip, as opposed to mechanical grip, but it’s grip all the same.

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That’s why everyone’s at it, because ultimately racing is about grip: the more grip you have the faster you can turn the bike in the corner, and the faster you do that the sooner you can lift the bike onto the fatter part of the rear tyre and use a big handful of throttle to rocket down the next straight.

Ducati and Aprilia currently lead the aero race, because they’ve hired F1 aerodynamicists, mostly from Ferrari, which knows much more about aero than anyone in MotoGP, even though it needs to apply its knowhow very differently to the dynamics of motorcycles.

Red Bull-backed KTM, which has always wanted downforce aerodynamics banned from MotoGP, has now accepted it’s got to get involved, so it’s using aerodynamicists from Red Bull F1’s team to catch up.

Honda and Yamaha didn’t want the aero war to get serious, either but they too have accepted that this is the way MotoGP is going, so they must also react accordingly.

Honda has car aero experience, from Formula 1 and GT car racing, so it’s using its own aerodynamicists to work on the RC213V.

Which leaves Yamaha, the only MotoGP brand without deep racing aero knowhow. Some factory team staff tell me they’re trying to convince Yamaha to hire F1 aero people, but so far, no luck.

Sepang’s year-opening three-day test had all five factories experimenting with new downforce aero and much more besides…


Aprilia RS-GP

Aleix Espargaro Aprilia in black carbon at 2022 MotoGP test

Espargaró’s 2023 RS-GP: exit ducts either side of the screen fire air from the main intake over the rider’s shoulders to smooth airflow and reduce drag


Last year Aprilia came closest to matching Ducati with its similar 90-degree V4 RS-GP and at Sepang had more updates aimed at closing the gap.

Aerodynamically, the 2023 RS-GP features a revised downforce fairing to improve ground effect and therefore grip. Aprilia also tested front-wheel ground-effect fitments, which are small but very close to the tyre contact patch, so they may offer a useful improvement.

Also new are exit ducts either side of the screen, which take flow from the air intake and fire it over the rider’s shoulders to smooth airflow, thereby reducing turbulence and drag.

Front wheel attachments on Aprilia MotoGP bike at 2023 Sepang testing

Aprilia’s front wheel attachments increase surface area at full lean to create a small amount of extra ground effect


Aleix Espargaró says the 2023 RS-GP is more stable, turns better and has a bit more power, but Aprilia has a more powerful engine on the bench in Noale, which will most likely be homologated for the season. This could be significant because both Espargaró’s and team-mate Maverick Viñales’ bikes were equal-fastest with Pecco Bagnaia’s Ducati at Sepang, at 209.7mph.

Miguel Oliveira’s arrival in the independent RNF Aprilia team could be great for Aprilia. He is a fast and cerebral rider who may prove to be very useful, because Viñales, who was as fast as ever at Sepang, tends to perform differently depending which side of the bed he gets out of in the morning.


Ducati Desmosedici

Ducati with black carbon fairing in 2023 MotoGP Sepang testing

Ducati’s revised 2023 diffuser fairing is slightly slimmer and was preferred by both factory riders: Bastianini and Bagnaia


Ducati appears to have maintained its advantage in pretty much every area – there were no less than seven Desmosedici riders in the top nine at Sepang.

The factory tried two aero directions: a revised version of its diffuser fairing and another version of the Aprilia-inspired ground-effect fairing it used at November’s Valencia tests. This is significant, for no other reason that this is the first time Ducati has copied a rival on aero design.

At Sepang the Aprilia-style fairing made the Desmosedici more stable on the brakes but the revised diffuser fairing was better in the corners, so both factory riders Pecco Bagnaia and Enea Bastianini will most likely continue in this direction.

Ground effect fairing on Ducati MotoGP bike at 2023 Sepang test

Ducati also tried a revised version of its bulging Aprilia-style ground-effect fairing but riders seemed to prefer the diffuser fairing


Bagnaia reported a slight increase in top speed but Ducati is working a lot on initial throttle response because the 2023 engine is a bit aggressive at the first touch of the throttle, which is hugely important to corner-exit speed. He also described a big step in electronics, although the bike’s handling is a bit more nervous.

Overall Bagnaia said the Desmosedici is in much better shape than this time last year, which didn’t stop him winning the 2022 title…

Luca Marini, who ended the test on top, riding a 2022 bike, said his machine has no negative points and the test went so well that he was able to do a sprint race simulation, during which he was “overtaking ghost riders”. That’s a rider in good shape…


Honda RC213V

Marc Marquez on carbon Honda MotoGP bike at Sepang 2023 test

Márquez started with four bikes – one old, three new – and gradually whittled that down to one 2023 RC213V but Honda still has a lot of catching up to do


Honda has a lot of work to do following three grim seasons, characterised mostly by Marc Márquez’s absence through injury and operations.

Márquez’s feelings were mixed at the end of the three days. He was delighted with his physical fitness – better than at any time since his career-changing accident in 2020 – but not so much with his machinery. He ended the three days tenths fastest, 0.777 second behind Marini and just behind younger brother Alex (Gresini Ducati), which must’ve made the journey home interesting…

After a total redesign of the RC213V for 2022 and so little testing time to get the bike right, Honda decided evolution not revolution is the way to go now for 2023. Márquez started the Sepang test with four bikes – one 2022 machine for comparison and three different 2023 prototypes, with different frames and aero. By Sunday he had whittled that down to one bike, suggesting that at least he’s found a direction.

Black carbon Honda frame for Marc MArquez at 2023 MotoGP Sepang test

Márquez tried this protype ground-effect fairing, without diffusers, but not for long


An Aprilia-style aero fairing appeared and then disappeared, Márquez preferring the diffuser fairing he had used since the final races of 2022.

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Honda’s new engine gives more torque but Márquez is struggling to put that to the ground due to traction issues. He thinks this may be trigged by a lack of turning – if you can’t turn the bike fast enough mid-corner you start accelerating on the edge of the tyre, which means no traction.

Joan Mir, who follows Pol Espargaró and Jorge Lorenzo as Márquez’s team-mate, seemed to get on better with the RC213V than expected. Going from an inline-four (Suzuki’s GSX-RR) to a V4 is never easy and yet the 2020 champ said he enjoyed his time on the bike and was making forward progress. However, like Márquez, he said Honda is still far from Ducati.

Mir’s former Suzuki team-mate Álex Rins ended up 19th, just over a tenth of a second slower than Mir. The top was covered by 1.097 seconds, around a two-minute lap!



Carbon KTM bike is wheeled in pitlane during 2023 MotoGP Sepang test

KTM’s first diffuser fairing (the ducts are front and low) was used by Brad Binder during the last two days of the test


Much was expected of KTM after an off-season spent working with Red Bull F1 aero experts. But the Austrian-based giant didn’t have a single bike – KTM or GasGas – inside the top ten at Sepang.

Pol Espargaró, back on an RC16 after two years at Honda, was the fastest RC16 rider in 13th, a fraction ahead of KTM’s Brad Binder.

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Binder spent the final day and a half using a new ground-effect diffuser fairing, with diffuser ducts similar to Ducati’s, but he was trying so many different set-up combinations that he wasn’t really sure what was better or worse. This will be confirmed by data analysis before the second and final pre-season tests at Portimao, on 11th and 12th March.

New team-mate Jack Miller, fresh from five years at Ducati, found the RC16 a tougher proposition, ending the tests in 18th, a second down on Marini. In effect he has travelled the opposite journey to Alex Márquez.

The Australian dedicated the tests to adapting his riding technique and making geometry and balance adjustments to the RC16, trying to make the bike turn better mid-corner, so he could fire it out onto the next straight. “I see positives in there,” he said. “I just need to ride in a way to exploit them.”

Jack Miller on carbon KTM in 2023 MotoGP test

Miller spent all his time on the non-diffuser fairing, first tried during the Valencia tests

Red Bull

KTM’s 2023 engine was designed for better throttle response and has more top end, but nevertheless Binder said it’s not easy to get the power to the ground, especially out of slower corners, a bit like Honda.

KTM is trying incredibly hard to close the gap on Ducati, partly by hiring numerous Ducati engineers, which is probably one reason why the latest RC16 engine sounds very much like a Ducati, especially on the all-important over-run, when riders need rear grip to help stop the bike.

I asked one of KTM’s Italian engineers whether he will need to learn to speak Austrian. “No,” he grinned. “They will speak Italian…”


Yamaha YZR-M1

Fabio Quartararo cornering in 2023 MotoGP Sepang test

Quartararo was fast on race pace but mysteriously slow with new tyres in all-important qualifying mode


Yamaha has had a grim time in MotoGP recently, with one world title (Fabio Quartararo’s 2021 victory) in seven years. That lack of success triggered the company’s biggest fightback since 2004, when it had considered quitting the premier class after two grim seasons.

Quartararo said on Friday that he had tested more new parts in that one day than he’d ever done in a three-day test with Yamaha.

The factory needs two major advances for 2023: more straight-line speed, so the M1 can at least race with the Ducatis and Aprilias, and more downforce aero. In the last few seasons the M1 has run minimal downforce aero because its inline-four engine didn’t make enough power to cope with the drag created by aero.

Thus horsepower is more important than ever because it now makes you faster down the straights and through the corners.

The 2023 M1 engine certainly makes more power. On day two at Sepang the M1 was only 0.5mph slower than then best Ducati, but on day three, when Quartararo focused on a bike fitted with Yamaha’s first ground-effect diffuser fairing he was 2mph down, a slight improvement on his 2.5mph deficit at last year’s Malaysian GP.

Yamaha diffuser fairing at 2023 MotoGP test

Yamaha was the last MotoGP factory to join the ground-effect race, with this diffuser fairing, first tried at Sepang


Quartararo likes the diffuser fairing, which he noted increases grip in slower turns (although, like all downforce aero, you’d expect it to work better at higher speeds). And he was “super-happy” with his speed on used tyres, in other words, his race-pace performance.

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However, he had one major an unexpected problem. He was unable to extract more speed from new tyres and was around a second slower than he expected. This would put him at least halfway down the grid. “And fighting for victory now comes 80% from your qualifying position,” he said. “I therefore end this test with mixed feelings.”

Team-mate Franco Morbidelli has changed his style in recent months, trying to ride more aggressively like Quartararo. He was up with the fastest riders on day one but also struggled to make a hot lap on new tyres.

Testing resumes next month at Portimao, when the lessons learned at Sepang, will be put into action at the track where the 2023 championship commences two weeks later, on 26th March. The track is very different to Sepang and so will be the weather, so the results could be very different.