MotoGP’s wheels that flex for more grip

MotoGP

Mugello tech roundup: what MotoGP’s wheel makers are doing to increase grip and reduce tyre-pressure problems, why KTM wants MotoGP aero banned, plus Honda’s new RC213V chassis

2022 Yahama MotoGP wheel rim

Latest OZ eight-spoke rims on Fabio Quartararo’s Yamaha. Silver treatment disperses heat and reflects heat from the brake discs

Yamaha

Author

Mat Oxley

When nine-times world champion Mike Hailwood was asked how his tyres had been during one of his 76 Grand Prix-winning rides he famously replied, “round and black”.

Even in those simpler times Hailwood was renowned for his technophobia, so God only knows how he would’ve managed with multiple rim sizes, numerous choices of compound, minimum tyre pressures and so on.

Front-tyre temperature and pressure are the big deal in MotoGP right now, because working out the right pressure will help you win the race, while a slightly incorrect tyre pressure will have you struggling in the pack. Even 0.05 bar can make a difference.

Which is why the two manufacturers – Marchesini and OZ – that supply wheels to the entire MotoGP grid are working harder than ever to keep front-tyre temperature and pressure under control.

Recently both companies have redesigned their front wheels to increase internal volume in an effort to reduce the pressure problem and have developed their own heat-dispersant and heat-reflective treatments.

Most striking are the latest eight-spoke OZ wheels used by the factory Yamaha team that use an almost chrome-like treatment. Obviously one aim is to disperse the heat from the rim and the tyre, but arguably even more important is reflecting heat away from the front discs, which is one of the main issues causing tyre temperature and pressure problems.

2022 MotoGP Mugello Ducati wheel

Marchesini wheels with heat-dispersant treatment on a factory Duke

Oxley

I spoke to both companies at Mugello and neither would allow me to photograph their wheels, except when fitted to a motorcycle, because they guard their secrets closely.

So what else could they do to further reduce the current problems? Formula 1 wheel rims are now finned, to increase surface area to cool the tyres but although Marchesini and OZ have considered these solutions they believe they will increase weight and affect aerodynamics too much. Whatever they are working on, again they kept their secrets close.

Of course, there are many other performances areas in which they are working.

Everyone knows about chassis flex and how creating the right amount of lateral flex in the frame and swingarm will make the motorcycle follow the track surface, thereby increasing grip, which improves turning and so on.

OZ and Marchesini make their rims flex for the same reason – to suit different chassis stiffnesses and different riding styles – but obviously they have much less room in which to work and getting it wrong would obviously have a catastrophic effect.

Rim stiffness is measured in four main areas – axial, radial, lateral and the general stiffness of the wheel hub.

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“We want to give riders a bigger contact patch in the corners, which we can do with different stiffness solutions in our rim designs,” said Andrea Pellegrini of Marchesini, who equip Aprilia, Ducati, KTM and Suzuki.

“We have various different wheel specs – seven spoke and five spoke, with different weight and stiffness. We offer all our wheels to all our teams and each rider can choose which he wants, depending on his riding style and also the stiffness of his motorcycle’s chassis. For example, one rider may prefer a certain spec because he feels more grip in the corners. Also, rim stiffness can affect braking performance.”

OZ wheels recently introduced eight spoke wheels, which they say gives them better control of rim stiffness and heat transfer.

“It’s always a compromise between stiffness, weight and inertia, because if you have too much inertia, for example, the motorcycle will not turn so well,” said Giulio Argenziano of OZ, who supply all the Hondas and Yamahas on the MotoGP grid.

“All the riders have different ways to ride and different motorcycles, so all these parameters are very important. And you need to take a lot of care because things like heat transfer can affect rim stiffness.

“We have a long experience in this field from working in Formula 1. We even work in the wind tunnel to see how we can help riders reduce front tyre temperature and so on.”

OZ wheels feature tiny dimples in the rims which are one of the few tiny features actually visible without seeing the inside of the wheel.

“The dimples give a bit more surface area and better stiffness at the side of the rim, without increasing mass and therefore inertia,” added Argenziano. “It’s a small thing but if you put many small things together maybe you make a 10 per cent improvement in performance.”

MotoGP riders and engineers will face an even bigger front temperature challenge at August’s Austrian GP at Red Bull Ring, MotoGP’s most demanding circuit for braking systems. For the first time all riders must run Brembo’s 355mm carbon discs, instead of the 340mm discs used at most circuits.

These big discs are necessary because the motorcycles keep getting faster, but the larger rotors come very close to the rim, which will only exacerbate issues with rim and tyre temperatures.

 

KTM uses new aero, wants aero banned

2022 KTM MototGP bike comparison

Spot the difference: Binder with old wings and sidepods at Jerez, then new wings at Mugello

Red Bull

KTM has a had a rough start to the 2022 MotoGP championship – just one dry-race podium, Brad Binder’s second place in the season-opening Qatar GP, and Miguel Oliveira’s victory in the rain-lashed Indonesian GP.

The RC16’s biggest change for 2022 was a radically different aero package – revised upper double wings and new, Ducati-style sidepods. The Austrian factory’s idea was that downforce aero had become so important in MotoGP that they must design the motorcycle around the aero, rather than treat the aero as an add-on.

But KTM’s aerodynamicists probably went too far in that direction, so at Mugello they introduced their second (and last, according to the rules) 2022 aero package.

“Before this year we tried to develop the aero package for a given bike setting,” said KTM MotoGP project leader Sebastian Risse at Mugello.

“This year we turned it around and basically set up the bike around the aero package – for sure it’s a more radical approach than previous years.

“Your performance depends on the front tyre allocation and how you stress the front tyre and what kind of drop [in tyre performance] you get, so now we’ve homologated our second aero package, which is a bit less radical, so when we encounter these kinds of problems we can better adjust to them.”

Risse refused to go into details about KTM’s new aero. The obvious difference is the removal of the sidepods. The new upper wings look very similar to the previous wings, so it’s likely KTM has made minor adjustments to angles and so on.

“A small difference makes a big difference – you can affect the total outcome without changing much,” added Risse.

“You have to see everything in the context of tyre allocation and set-up. We used the whole weekend at Mugello to explore the set-up for this. I don’t think we’ve finally arrived at the point where you can say this is the perfect set-up.

“We really believed that this latest aero philosophy would work better and finally we found a set-up that worked well but you saw that we struggled during the weekend. You have to invest a lot of time, and you will not see the results straight away so it’s work in process. The good thing is that we now have an alternative for certain tyres and tyre allocations.”

“What do wings really bring to the show?” Miguel Oliveira

KTM rider Brad Binder had an astonishing race at Mugello, from his usual lowly grid position. The 26-year-old South African has always been more of a racer than a qualifier, so after starting from 18th he somehow fought his way through to seventh at the end of the first lap, completing the race in the same position, only four seconds behind winner Pecco Bagnaia.

Team-mate Oliveira, who finished second at Mugello last year, came home ninth ninth, a further seven seconds back.

“We took off the side pods to make the bike more agile and less critical on the brakes and the bike seems to work a bit better,” said Oliveira.

“But now we find that the setting is so different, so we need to adjust it a bit more. We will keep both aero options, so we will see which works better at every track.”

Oliveira had a huge scare on Friday morning in FP1, when he ran onto the grass at 200mph before Turn One after Aleix Espargaro had drafted past him. The 27-year-old attributed the incident to the turbulence and dirty air created by MotoGP’s current downforce aerodynamics.

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“Aleix got stuck in my slipstream and that pushed me out,” said Oliveira. “It’s the aero thing, the turbulence created by the dirty air. There’s a place where you are near the bike, when you go into the slipstream you catch the slipstream and then you want to get out of there as quick as possible. So you’re in the dirty air and then immediately you go into the clean air.

“He got sucked in and that’s what really pushed me out. It was a combination of bad things.

“That’s a quite a particular place [Mugello’s left kink before Turn 1] because we come over a crest, there’s the wall to the left, then when you sit up there’s a lot of wind coming all of a sudden, plus we are using a bit of lean angle, so it’s borderline.”

Both Oliveira and KTM engineers are some of the people in MotoGP pit lane who think it’s time to ban downforce aero.

“I’m all for innovation and performance but when this kind of thing happens it makes you reflect,” added Oliveira after his FP1 moment.

“Should we really be with the wings? What do they really bring to the show? And maybe it’s a bit dangerous, so we need to address it quite seriously. But it needs to come from all the riders, not just from one guy or from one constructor, pushing to have aero or to not have it.”

Oliveira believes that limiting downforce aero designs wouldn’t fix the problem.

“I think if you limit it you’ll end up with the same situations because some factories have more knowledge than others, so if you limit the aero the guys with more experience will still have more. I think we either go with full aero or without, to zero.”

But would it be possible to race 226mph motorcycles with no front downforce, because the bikes are just about trying to take off at that speed?

“Yes, we raced for many years without wings,” Oliveira answered. “You’d use less power, you’d have to manage the situation more and you’d have to be more of a rider, so I think it’s a good solution.”

Risse agrees that banning all downforce aero is the right way to go.

“We would absolutely rather race without the wings,” he said. “But when this aero door is open and when it’s legal to do these things then you have to do them.

“I think aero has affected MotoGP development quite a lot, aside from the pure aerodynamics, because you have very different problems with it. For example you can use very different engine performance, so the whole path that MotoGP has taken has been dictated by it. At KTM we don’t think it’s good for the sport and we still don’t think it’s particularly safe to go this way. We would be happy if downforce aero was stopped but we are not the only ones to make the decision.”

 

Honda’s new RC213V chassis

22 Honda frame

Spot the difference: standard RC213V frame (left) and revised frame

Oxley

Honda had its first major chassis upgrade at Mugello, with Marc Márquez racing the latest chassis before flying to the USA for a fourth operation on his two-year-old right-arm injury.

The only easily visible difference between the old and new frame and swingarm is the swingarm pivot point. It would seem that Honda is playing with chassis stiffness to make the TC213V turn better. The new design may also allow mechanics to change pivot height more quickly, so they can make adjustments during practice sessions, because the all-new 2022 RC213V is still in the early stages of its development.

Turning is always important in MotoGP, because the quicker the rider can turn the motorcycle in the middle of the corner the sooner he can pick up the bike and open the throttle.

“As soon as you improve in one area you lose in another” Marc Márquez

“We are trying to understand the way to turn better, but it’s always true that as soon as you improve in one area you lose in another,” said Marquez at Mugello.

“We are trying to understand the way to turn better, the way to understand the front tyre better and the way to turn in a shorter time. In MotoGP if you take a long time to turn the bike you cannot use the power, so you lose tenths.”

The new chassis was one reason why Marquez decided to continue riding over the weekend, after taking the decision on Friday to undergo surgery.

“I worked a lot during the weekend for Honda, giving my input for the future,” he added.

Honda’s 2022 RC213V is the company’s first full MotoGP redesign in a decade or so and the company’s difficulties with the machine highlight the problems of trying radical technical changes at a time when MotoGP’s current trend is to add more races and reduce testing.

This year’s pre-season testing programme was the shortest in many, many decades: two days at Sepang (the second afternoon in the rain) and three days at Mandalika, where the track was in such poor condition that the data and info gathered wasn’t of much of use. This doesn’t encourage manufacturers to make anything but minor changes to their motorcycles, year by year.

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