Aprilia may race carbon-fibre RS-GP next week at Red Bull Ring!

KTM was the biggest improver going into this season. A major overhaul of the RC16 – its aero, engine, chassis and perhaps most dramatically its holeshot/rode-height device – transformed the RC16 into a bike that can take the fight to Ducati when things fall into place.

Meanwhile Aprilia’s RS-GP, which was Ducati’s biggest 2022 rival, stumbled into 2023. Maverick Viñales chased Pecco Bagnaia at the season-opening GP but then not a single podium – from four riders – for three months, until Aleix Espargaró’s third place at Assen and finally, his victory at Silverstone.

KTM has improved for two main reasons: the Austrian factory and its Red Bull sponsor throw huge resources at the project, and have aggressively hired a bunch of Ducati brains.

There’s no love lost between Aprilia and Ducati, so it seems like the Noale factory prefers to go its own way. And of course the biggest engineering signing of them all – Gigi Dall’Igna – went in the opposite direction, from Aprilia to Ducati.

So what was up with Aprilia at those six rounds, between Portimao and Assen?

Front tyre temperature and pressure became a real issue with the RS-GP and anyone with half an interest in MotoGP knows that those two factors currently have a bigger effect on performance than just about anything else.

At Jerez the RS-GP’s front tyre ran 11 degrees hotter than any of the rival bikes, which prevented Espargaró from joining the Ducati/KTM battle at the front. This was most likely a bike balance and/or downforce aero issue, overloading the front tyre. Aprilia seems to have this sorted now, but we’ll have to wait for another hot race at a track that gives the front tyre a difficult time – like the Red Bull Ring – to be sure.

Aprilia’s other issue was poor starts, which exacerbates the front-tyre problem because riders get stuck in the pack, surrounded by a few boiling-hot 300-horsepower MotoGP bikes.

“Our main weak point is the start,” said chief engineer Romano Albesiano a couple of months ago. “We’re not worse than last year but clearly our competitors have improved, especially KTM, who have done some special stuff in this area, which is working incredibly well.”

Silverstone suggested that Aprilia has definitely improved its starts, with a new clutch and revised launch control.

Aero upgrades at Silverstone – a modified fairing to increase rear downforce in the corners and revised front-wheel fairings to cut through the air better – also made a difference.

Of course, Silverstone’s flowing curves suit the fine-handling RS-GP. The next challenge is stop-and-go circuits, like the Red Bull Ring.

Ducati has a major advantage at this kind of track, because the Desmosedici puts much more torque to the ground than other bikes when exiting slow corners, and doesn’t pitch forward so much during braking, which allow riders to use lots of rear brake to stop the bike quicker.

So these are the areas where Aprilia needs to work. And perhaps its brand-new carbon-fibre chassis could help.

Test rider Lorenzo Savador’s initial feedback during last week’s Misano tests was positive, so the factory is now running ongoing evaluations before making its decision about the Red Bull Ring.

Racing the new chassis as soon as possible makes all kinds of sense, because there’s nowhere better to evaluate new solutions than in the white heat of a racing weekend.

But why a carbon-fibre chassis? MotoGP’s minimum weight limit is set very high – at 158 kilos – to discourage expensive weight-saving developments. World Superbike’s minimum weight is 168 kilos; thus a cutting-edge prototype gets to weigh just ten kilos less than a road bike. In 1990, the 500cc/MotoGP minimum weight was 115 kilos, against around 160 kilos in WSB!

So, what’s the point of running a lighter chassis in MotoGP if the minimum weight is so high? Because if you save weight in one area you can spend it elsewhere, where it may improve performance.

Aprilia knows that one of its biggest disadvantages against the Ducati is the Desmosedici’s lack of pitching on the brakes, which allows riders to use the huge grip of Michelin’s rear slick to stop super-quick, which also takes load (and therefore risk) away from the not-so-good front slick.

Perhaps rebalancing the RS-GP with the weight saved by the carbon-fibre chassis will help engineers improve the bike’s braking balance? And there are many other potential benefits.

Carbon-fibre allows you to adjust the flex and strength character of the chassis in every area, by using different carbon weaves, different layups and so on, so engineers can decide that they need the frame to twist in a certain way at a certain stage of the corner and make it do exactly that. This is much more difficult to achieve with metal. And if Aprilia can gain a tenth or two per lap through carbon-fibre it will win more races.

Albesiano is also very keen on introducing the Meredith effect to MotoGP. This phenomenon can create forward thrust using the hot air passing through a cooling duct behind the radiator, via the expansion of the hot air in the duct. The concept was first used effectively during the Second World War in the P-51 Mustang fighter. It’s still used in some car-racing series. Certainly, a carbon-fibre chassis should make it easier to create a Meredith duct on a MotoGP bike.

Carbon-fibre chassis are nothing new, of course. Multiple British champion Niall Mackenzie raced a carbon-fibre Armstrong 250 GP bike in the early 1980s, I rode a carbon-framed bike at the Suzuka 8 Hours in 1985, designed by Japanese car constructor Dome Racing, and Cagiva’s 500 GP bike briefly ran a carbon-fibre chassis in the early 1990s, created by Piero Ferrari, Enzo’s son.

But these were early days, when the wonder material – which can be up to five times stronger than aluminium, weight for weight – was less well understood.

Cagiva rider Randy Mamola declared Ferrari’s chassis too stiff. This was around the time when engineers began to understand lateral flex – which has the chassis flexing minimally at full lean, so the tyres better track the asphalt to improve grip and therefore turning – for the first time.

All these bike people were most likely inspired by John Barnard, who in 1981 designed the first full carbon-fibre monocoque Formula 1 car, the McLaren MP4.

Two decades later Barnard was employed by ‘King’ Kenny Roberts to work for his MotoGP team. Barnard’s work at Team Roberts was limited by lack of budget but he had no doubt that carbon-fibre was the way to go.

I spoke to Barnard in 2011 when Ducati abandoned its carbon-fibre chassis, following pressure from Valentino Rossi, who was having a nightmare on the Desmosedici. At the time the story went that the chassis was too stiff, just like the Cagiva’s.

“I don’t buy any of that,” said Barnard, who discovered the joys of carbon-fibre during a visit to British Aerospace. “If Valentino needs the chassis to flex in some way, then Ducati need to determine what bit needs to flex and then make it flex.

“The problem is that at some point Valentino probably turned round and said, ‘Why don’t we make a frame like the others, because I know that works and I know I can win’, and with a rider of his calibre that’s very difficult to counteract. That tends to be a biker problem – they are very anti-different and very anti-new. And if something doesn’t work out of the box then it’s no good, it won’t work is the attitude.”

Barnard encountered this issue when he worked for Roberts.

“Kenny would say things like, ‘a carbon swingarm won’t work, full stop’. I know he had one made some years before by Lotus, but ‘did anyone know how stiff it was supposed to be and what they were trying to build’?

“I started trying to get a handle on the numbers: chassis stiffness, centre of gravity, aerodynamics and so on. The problem is that you can’t just sit down and make a frame or swingarm without some numbers. Lateral flex, vertical flex and all these things may be necessary, but you need to know the numbers. It’s not some mystical science, there is a way to find out.

“With rider feel you’ve got to determine what the rider wants to feel, what gives him that feel and then you’ve got to turn that into hard facts. Once you know the numbers you know what you are trying to create and you can do it.

“Carbon gives you more options than you can shake a stick at – you can change the material, the layup and the direction of the fibres to give different properties, which you can’t do with a metal frame or swingarm.”

“So it’s very easy to tune things with carbon, but you’ve got to know what you’re trying to achieve and you’ve got to know the numbers you’re looking for, so the first thing you’ve got to do is try and find those numbers. That’s where I was coming from.

“I brought Nick Chapman [a former stress engineer in the Ferrari and Benetton F1 teams] into the team, who is an exceptionally clever calculations guy, to help decipher some of the numbers from the chassis test apparatus we bought.

“Once we got a pretty decent handle on where we were with stiffnesses and all the rest of it I wanted to have a go at making some chassis parts. But that needs resources, time and so on and that’s just not there in bikes, the budget just isn’t available.”

Many MotoGP engineers believed the Desmosedici’s real problem – both with its tubular steel and carbon-fibre chassis – was that the engine was a major stressed member in the centre of the chassis. And since the centre of the chassis needs to laterally flex during cornering, that’s not an ideal design concept.

“I don’t buy that either,” added Barnard. “My theory is that the engine should be part of the stressed member and if the chassis needs more flex, put it in somewhere. Just determine what area needs to flex and then make it flex – I’m sure that’s doable.”

Barnard is one of motor sport’s greatest original thinkers. During our conversation we also discussed aerodynamics.

“Aerodynamics at full lean is another aspect,” he said. “Because when you’re talking 60 degrees of lean you’ve got a lot of fairing close to the ground, so ‘what’s that doing and what could it do is another question’?”

In other words, Barnard invented Aprilia’s ground-effect fairing 21 years before it appeared last season!

More than a year after Aprilia introduced its ground-effect fairing at Assen in 2022, Yamaha finally raced its ground-effect fairing for the first time at Silverstone.

Fabio Quartararo used a new upper and lower fairing in Sunday’s race, with double upper wings – similar to those used by Ducati and KTM for the last few years – plus diffusers that accelerate airflow beneath the fairing at full lean to create an area of lower pressure which sucks the bike into the asphalt, improving grip.

The current YZR-M1 doesn’t really have enough power to carry that much aero, so what Yamaha is doing is laying the foundations for 2024, when the M1 will hopefully have a more powerful engine, partly designed by former Ferrari F1 engineer Luca Marmorini.

“We will keep this fairing,” said Quartararo, who qualified last in Saturday’s rain-lashed qualifying sessions and finished the race 15th after pitting to swap bikes because his fairing had been torn off during a collision with Luca Marini. “It’s really interesting because the handling wasn’t too bad and hopefully the downforce will be better.”