MotoGP’s new tyre-pressure rules: ‘As soon as you reach 2.2 bar you crash’

MotoGP

Next week’s opening pre-season tests at Sepang will be the first time MotoGP uses its spec tyre pressure sensors in preparation for the introduction of new minimum-pressure rules. So how will these new regulations affect the riders, the manufacturers and the spectacle?

2022 MotoGP Australian GP

Last year’s Australian GP was a thriller but at some tracks high front tyre pressures can reduce overtaking and hurt the MotoGP show

Michelin

Mat Oxley

What will be the biggest challenge faced by MotoGP riders and teams in 2023?

Winning races, of course.

But to win races riders will have to deal with something they’ve never had to deal with before: minimum tyre-pressure rules.

This will be a hugely tricky balancing act with the all-important front tyre, because the window between running below the minimum limit, which will get you disqualified, and going too high, which will probably cause you to crash, is very narrow – around 0.3 bar/4.3psi.

This is one reason why front-tyre pressure is one of the most important performance factors in MotoGP.

Last season (according to one engineer with whom I recently spoke) every race winner was under the 1.9-bar minimum, which wasn’t enforced at that time, and at some races the first ten finishers were under, so there’s an obvious advantage in running slightly below the limit, to expand the contact patch for more grip.

tyre engineer motogp

All MotoGP wheel rims will be fitted with spec LDL tyre pressure monitoring units for the first time this season

Michelin

And to avoid crashes… You know when you see a rider unexpectedly lose the front while braking into a corner, with hardly any lean angle? That’s because the front tyre has gone over pressure, shrinking the contact patch and thereby reducing grip.

“It’s a rider’s nightmare, because as soon as you reach something like 2.2 bar then you crash,” another engineer told me.

This is KTM’s MotoGP project leader Sebastian Risse… “We made some statistics about our riders – how often they crashed and at what pressure – and it couldn’t be clearer that there’s a certain threshold of high pressure, which if you go over it, you will barely survive race distance.”

MotoGP’s original plan was to enforce the rule last year but this wasn’t possible, for two reasons. First, because different teams were using different brands of TPMS (tyre-pressure monitoring systems). Second, because the TPMS signal travelled via the motorcycle’s datalogging system, so any engineer who wanted to cheat could easily alter the pressure values by a few tenths of a bar to stay within the rules. This year the signal will be sent directly via telemetry from each TPMS to race direction.

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To stay legal riders need to keep above the minimum limit for at least 50% of a grand prix. The rule will also apply in qualifying, when riders will lose any lap when they’re under pressure. Qualifying infractions will be immediately communicated to teams, so they can tell their rider to go again. In Saturday’s new sprint races the minimum pressure will need to be reached for between 30 and 50% of race distance, depending on the number of laps.

By the way, the limit for the rear tyre is 1.7 bar, but rear pressure is rarely, if ever, a concern.

Michelin may slightly lower the front minimum from 1.9 to 1.88 bar for 2023, with the limit possibly changing fractionally from one circuit to another, according to track and weather conditions. The company doesn’t want to go much lower than 1.88 due to concerns over damage to tyre casings, even though riders have run a few tenths lower without problems.

What effect will the enforcement of the pressure rules have on the racing?

“I think with this kind of limitation we will see less show, less overtaking,” says Diego Gubellini, crew chief to 2021 MotoGP champ Fabio Quartararo. “Because if you cannot go under a certain limit then you will suffer more when you are following another rider, then you cannot overtake him, even if you are faster, so I think this isn’t the best solution for the show.”

tyre engineer motogp 2

Michelin’s rear slick – rear tyre pressure is rarely, if ever, an issue in MotoGP

Michelin

There’s already less overtaking in MotoGP than there used to be, so if Gubellini’s prediction is correct, this is another concern for the championship, which is fighting to rekindle interest.

Michelin’s front slick has caused high-pressure problems for riders for at least five years, but increased machine performance – thanks to more straight-line speed, stronger brakes and, most of all, downforce aero – has made the situation much worse.

The problem is at its worst when a rider is chasing a rival, because once the following rider gets close, the heat from the leading rider’s machine overheats the chasing rider’s front tyre, raising tyre pressure and reducing grip. There is really only one thing the second rider can do in this instance: slow down, wait for the pressure to drop (all MotoGP bikes have pressure gauges on the dash), then try again.

“Even before all this we had front-tyre pressure problems, but you could come out of the slipstream and survive,” adds another engineer. “Now, with the extra speed of the bikes and all the downforce, it’s become much more critical because of the extra load on the tyre.”

Teams and manufacturers have been working hard on this problem for a while, especially in the build up to the new season, and some will have done a better job than others.

But even if some engineers have worked out how to keep the pressure above the limit their efforts may be for nothing if the race doesn’t go the way they predicted.

“You can go wrong with the pressures if what you assume will happen in the race doesn’t happen,” an engineer explains. “For example, if your rider starts from the second row and you think, ‘Right we’ll have three or four riders in front of us, so I’ll leave a 0.1 or 0.15 bar margin above the limit’, but then you holeshot and you’re leading, it’s like, ‘Oh shit!’. Because you’ll end up getting disqualified because your pressure won’t get up to the pressure you predicted.” And there’s nothing a rider can do about that when leading a race, except drop back into the pack.

Therefore the real target is to redesign your motorcycle to suit higher pressures, if that’s possible.

MotoGP technical director Danny Aldridge

MotoGP technical director Danny Aldridge, who’s been working on the tyre issue since teams asked him to police pressures

Dorna

“The challenge is to make the bike rideable, even with quite high front-tyre pressure,” says HRC engineer Takeo Yokoyama. “And if you are successful you will have a huge advantage, because imagine that only your bike can manage 2.3 bar, while the other manufacturers can’t go to 2.3.

“It’s about weight distribution and how you dynamically transfer weight from one tyre to the other. Airflow also makes a difference. The tyres are the same for everybody but it’s not easy – in fact it’s a huge task, a huge challenge.”

Yokoyama also agrees that the rule will change the racing. “A lot, a lot, a lot,” he adds.

The situation is so complex that the rule won’t be enforced until round four, April’s Spanish GP, so that riders, teams, manufacturers and MotoGP technical staff will have the first three races to get used to running with the spec TPMS, provided by French company LDL. And even then, if too many riders and teams are struggling to stay above the minimum pressure, or there’s issues with the TPMS and its telemetry system, then the teams will be allowed to vote for a further delay.

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“This isn’t an easy thing for everybody to get right, which is why we’ve taken a long, long time to get here,” says MotoGP technical director Danny Aldridge. “If everyone is happy after the first three races then we will strictly enforce the regulation from the fourth race. But if not, we can extend the period before we introduce it.

“The whole reason this came about is because a few years ago some teams came to me and said, ‘We’re following the rules but we’re not sure the guys in the next-door garage are’, so it was teams that have brought this upon themselves.

“I hope there’ll only be a bit of a panic at the first few races, then once everyone understands the situation they’ll manage it and if they make a mistake they’ll have to take the consequences.

“MotoE has spec TPMS units and minimum pressure rules, and we’ve had a few riders disqualified for going under, but teams have mostly got used to it, so they’re managing it better. In MotoGP maybe there’ll be three or four disqualifications in the first season and then maybe the following year there’ll only be one or two.”

Obviously it would be a disaster for the MotoGP show if a race winner is stripped of victory for being one- or two-tenths of a bar under the limit, but Aldridge says that once the rule goes live it will be enforced like any other.

“What’s everyone going to do, cheat like mad in first three races?”

“The pressure data will go to race direction, so if they inform me that a certain bike hasn’t kept the required pressure for 50% of the race that bike will be summoned to technical control, where we will check the data and make sure there’s nothing wrong with the sensors.

“It’s no different to weighing a bike to make sure it’s above the minimum weight, taking a fuel sample or checking the software download to make sure the team is using the right software. Obviously we don’t want a rider disqualified every weekend, but rules have to be abided by.”

If there is a rule, of course. If the teams do decide to delay the rule, possibly until 2024, MotoGP will be where it was last year, with teams cheating with impunity. But maybe you can argue that if they’re all cheating then it doesn’t matter…

And even if the rule is implemented at Jerez, there will be questions. “What’s everyone going to do, cheat like mad in first three races?” wonders one engineer.

Pol Espargaro leads Jorge Martin in 2022 Argentina MotoGP round

Rules will not apply for first three 2023 races

Dorna

Of course, this entire problem could probably be solved by a new front slick, designed to cope with the extra stresses caused by downforce aero and other tech improvements. Michelin has promised a new front in recent years but it’s been delayed and delayed, with a new tyre now unlikely before next year at the earliest.

On the other hand, Michelin motor sport manager Piero Taramasso, argues that the problem isn’t of his making.

“When you have a control-tyre championship, then the manufacturers have to design their motorcycles around the tyres,” he says. “By adding all the aero and the ride-height devices, then they aren’t designing their motorcycles around the tyres.”

It’s a complicated state of affairs, some might even say it’s a mess, but we won’t really know what’s going to happen until the Spanish GP at the earliest.