Poor old Valentino Rossi. Another year and he still sounds like a broken record. At Jerez his problem was the same as it’s been for the last few seasons: too much rear-tyre temperature and therefore not enough grip or tyre life.
Michelin has heard the story so often that its MotoGP chief Piero Taramasso was moved to suggest that the problem was Rossi’s own. “Rossi has a particular style – he leans off the bike less than the others, which stresses the edge of the tyre more, so the temperature rises,” said Taramasso on Friday.
The seven-times premier-class champion didn’t appreciate the lesson in riding technique and responded robustly on Saturday.
“I don’t agree with Taramasso,” he said. “If you look at photos it’s clear I’m a long way out of the bike, because we work a lot on this. With the Bridgestones I was more out of the bike than I am now. With the Michelins you can be too far out.
“My position on the bike isn’t the problem. For example, [Andrea] Dovizioso is another rider whose style isn’t so far out of the bike. So for me this isn’t the problem. Usually in my career I always prefer hard tyres, both front and rear. In the past I’ve ridden the best races of my careers with hard tyres. Now the Michelins are very soft – very soft casing and very soft rubber – so for me it’s not easy.
“Also, I’m taller than average and although I’m very skinny my weight is quite high, because I’m quite tall. But on the other hand I agree with Taramasso that the problem is mine, not Michelin’s, because the other guys are fast, so I agree with him that we need to find a way, but I don’t agree that I’m not far enough out of the bike.”
In Bridgestone’s final season as tyre supplier, he challenged for the title. In the four seasons since then, he has won just three races
Motorcycle racers have been hanging off their motorcycles to go fast since the early 1960s. Australian Tom Phillis was probably the first to use the technique successfully when he won the 1961 125cc world championship. Phillis began shifting his weight to the inside of the bike to improve handling. Leaning off achieves this by reducing lean angle and reducing the forces on the tyres.
Anyone who leans off their motorcycle does so for these reasons and to reduce centrifugal force while cornering, which helps the bike turn. During the last ten years, MotoGP riders have leaned even further off their bikes in search of faster lap times.
When Rossi arrived in 500s his upper body stayed pretty much in line with the rear tyre. More recently the rear tyre and upper body make a V shape, with the upper body at an even more extreme angle. Comparing photos of Rossi and Yamaha team-mate Maverick Viñales suggest that the Spaniard does hang off slightly more, but he’s lighter, so the physics are different.
Rossi is certainly correct when he says has always preferred harder tyres, both in construction and compound.
He grew up on Aprilia 125 and 250cc GP bikes – very taut chassis and very stiff tyres – which gave him the feel for tyres that don’t deflect (squish) too much as he puts load into them entering and exiting corners.
After several years with Aprilia he graduated to the 500 class in 2000. The five premier-class titles he won with Michelin were all during the era of open tyre competition, when top riders could request pretty much whatever constructions and compounds they desired.
In 2008 he switched to Bridgestone, which produces the stiffest tyres in bike racing. And he won two of his greatest titles with the Japanese manufacturer – with open-competition Bridgestones in 2008 and with spec Bridgestones in 2009 – against the toughest opposition.
In 2015, Bridgestone’s final season as MotoGP tyre supplier, he won four races and challenged for the title. In the four seasons since then, he has won just three races.
Rossi during Jerez practice
His rear-tyre problems are obviously complex, because they’ve been there throughout much of the last four and a bit seasons. Does he load the tyre too much or too little? Does his bike set-up load the tyre too much or too little? Because dropping out of the sweet spot in either direction can have a similar effect.
The big question now is can Rossi unlock the secrets of Michelin’s current rear to get closer to the front and challenge for podiums?
When he tested Michelin’s 2020 rear slick last year he seemed optimistic. “It looks like Michelin has made a very good job because you have more grip on the edge,” he said last September.
In theory the tyre’s bigger footprint should deliver lower temperatures, because a larger contact patch spreads the load and the heat, which should help him.
However, if the tyre gives Rossi more edge grip and longevity it gives everyone more edge grip and longevity, so he’s back where he started. On Sunday at Jerez he was running just inside the top ten until he parked his YZR-M1, most likely due to an electronics failure. Last year four of his last five results were eighth-places finishes, so he’s certainly made no improvement going into 2020.
However, his garage is confident that his results will improve. Rossi has only just started a new rider/crew chief relationship with former VR46 Moto2 engineer David Munoz, who hadn’t worked in MotoGP until last November’s Valencia GP, so Munoz is very much still building his MotoGP know-how. He is young, keen to learn and working well with Rossi’s crew.
During the first dozen laps on Sunday Rossi lost around four-tenths per lap to winner Fabio Quartararo and two or three tenths to the group that ended up battling for the podium. This isn’t an insurmountable disadvantage, especially since he may know what he needs to do.
“When we look at the data of Maverick [Viñales] and Fabio [Quartararo] we are very, very similar,” he said. “Maverick is very strong on braking – it looks like he’s able to stop the bike a bit better than me.”
Rossi isn’t stupid. He knows he won’t challenge for the title like he did all those years ago
This, therefore, is where Rossi needs to work. If a rider cannot get the bike stopped as he wants it sets in motion a chain of events that ruins not only his lap times but also his tyres.
If he gets into the corner too hot, he will have to work the bike and the tyres harder to make the corner. And most likely he will be slow through the corner, so he will instinctively compensate by using more throttle on the exit, which burns the tyre. One small problem can lead to many more problems.
Braking at MotoGP levels isn’t a simple process. Michelin’s front slick isn’t good enough to do all the work alone, so riders use the rear tyre during braking more than they did with the Bridgestones. Getting the bike balance just right so the rider can play with the front and rear brakes into corners is a tricky balancing act.
Then there is the issue of Rossi’s size. The 41-year-old is the second biggest rider in MotoGP, standing at 181cm and 69 kilos. By comparison, the average height and weight of the top-five finishers at Jerez was 172cm and 65 kilos. In combined bike/rider weight terms this is a difference of around two per cent. Surely, that’s nothing. Maybe, maybe not, but in these days of ultra-tight competition, a little can be a lot. For example, a two per cent difference in lap times at Jerez is around 2.5 seconds! His height doesn’t help either, because exiting corners he can’t move his backside as far forward as others can, so he struggles to reduce load on the rear tyre.
Rossi in 2001, when lean angles and rider position were less extreme
Rossi isn’t stupid. He knows he won’t challenge for the title like he did all those years ago, but he believes he can still fight for podiums, if he can get the bike to do what he wants it to do. And that’s enough to keep him motivated, with the dream that one day circumstances may conspire to put him on the top step of the podium again.
Michelin’s 2020 tyre doesn’t seem to have changed much for Rossi, or for other riders of inline-four MotoGP bikes, the Suzuki and Yamaha, but it has changed things for some V4 riders.
While GSX-RR and M1 riders use classic, arcing lines through corners to exploit the easy-riding nature of an inline-four MotoGP bike, riders of Ducati’s Desmosedici and Honda’s RC213V V4s have to use more acute cornering lines to get the best out of their bikes, so they play more with rear grip. The problem is that the new rear’s improved grip can overpower the front tyre
“The new Michelin has better grip, so its exit grip is good, but in corner entry it pushes the front more,” said Honda’s Marc Márquez. “Normally more grip at the rear is better for Yamaha and Suzuki because they ride more with the rear tyre.”
“The tyre is really different,” said Dovizioso. “It doesn’t seem to affect some bikes that much – it looks like Suzuki and Yamaha aren’t struggling, but we are struggling. The tyre works in a different way, so the way you brake, how you enter, the way you release the brake, how you open the throttle and how you slide, everything is a bit different. We have to adapt and it’s not easy.”
Petrucci went into more detail. “The Ducati riding style is to slide a bit in corner entry to turn the bike, but with this tyre it’s really, really difficult, especially braking into tight corners. We need to work with the engine-braking to slide the tyre, but we are still missing something. Also, we need to slide the bike in entry to unload the front tyre, but with the new rear’s extra grip I can feel the tyre pushing the front tyre.”
More grip at either end of the motorcycle changes front/rear traction balance, so engineers must work to restore that balance, distributing load and grip between the front and rear tyres to maximise entry, mid-corner and exit performance.
When Michelin returned to MotoGP in 2016 its tyres transformed the balance of MotoGP bikes. Bridgestone’s front slick was better than its rear slick, while Michelin’s rear is better than its front; so the bikes had to change and the riders had to change to make the lap time in a different way.
At first riders kept crashing, because when they got on the throttle they shifted load to Michelin’s grippy rear tyre and unloaded the not-so-grippy front tyre. This started happening again at Jerez – during the early laps of the race both Viñales and Márquez lost the front in a big way.
“On Wednesday and Friday I was already having some moments at the point where I release the brake and start to tap back on the gas,” said Miller. “I saw the same in the race, when Maverick had that big moment soon after the start and when Marc made that spectacular save. Both of those happened quite late in the corner, when they were getting back on the gas. With the way the track was you had to be quite patient, that was the key.”
Who knows, maybe Márquez lost the front and then the rear when he crashed in the final stages of the race? Only the world champion and/or his data will be able to tell us exactly what happened.
The important thing to remember is that Sunday was the first race with a new rear that is having a major effect on the behaviour of some bikes. This Sunday at Jerez and over the coming weeks and months the riders, teams and factories will further unlock the secrets of the tyre. This story is only just beginning.