In a race red-flagged and restarted after Maverick Viñales jumped off his brakeless Yamaha at 135 mph, the outcome looked like a straight duel between Jack Miller on Ducati and pole-sitter Pol Espargaró on the now-very-fast KTM. But that failed to consider the readiness of third-place rider Miguel Oliveira (on Tech3 KTM) to exploit any mistake by the lead pair. When they went wide on the final lap, he darted through to win—his first win in MotoGP.
Fortunately Viñales slid to a stop uninjured but his bike burned in the Airfence.
In the first start it had looked like success for Suzuki’s Joan Mir, who had fought clear and had the pace to win. But on lap 17, as Viñales approached turn 1, his brakes gave him the same non-choice that faced Eddie Lawson when one caliper’s brake pads fell out at the Laguna Seca USGP in 1990: Either instantly jump off, converting his leathers into a giant brake shoe, or go into the barrier with the bike. Viñales jumped. By rule, the race was stopped because a crash barrier had been damaged.
“I started to lose front brake pressure. I was trying, trying. I went wide one time.”
To rest the brakes, “I made three very slow laps, then I pushed again.
“I think the parts go away on the brakes. I understood very well that the brake was broken or something, so I decided to jump.”
Alex Márquez said, “Then suddenly when we arrived in the first corner I saw like some small black parts going out from his bike.”
This brake problem is not new. Valentino Rossi said, “In these last two weekends we were on the limit with the brakes, especially with the Yamaha.”
Fabio Quartararo, Rossi’s teammate, said, “The brakes? I felt the lever getting soft.
“In braking I went long twice, once because of me and once because of the brakes.”
After brake problems at Jerez, most of the Yamaha riders switched to the 2020 “evo” finned Monoblock aluminum caliper (it is said to operate cooler and contain less fluid than the previous design), but when Viñales didn’t get the feel he wanted from the new equipment, it was decided to stay with the previous calipers. Yamaha team manager Massimo Meregalli added, “Probably because he was behind other riders he couldn’t cool down the system, and after the fifth lap he felt something but tried to manage.”
“This track is very severe with the brakes,” Rossi also said. “Everybody suffers. If you see, everybody has big air ducts on the brakes (carbon fiber air scoops are visible in photos), also the other manufacturers.”
He further explained “…Yamaha suffers more also because we try to gain (back) in braking what we lose in the straight, because our bike is slow but it’s good in braking, so we try to brake very hard.”
Most riders are now using the 340mm-diameter Brembo carbon front discs, supplied in standard and heavy weights. Save for Ben Spies’ big Motegi brake problem in 2012 and some problems at Phillip Island, brakes have not been much in the news. That has clearly changed.
Despite claims that Yamaha’s early season engine warnings (red means stop) have been fully corrected, the riders seem to have a different opinion, and there are rumors of problems with the valve operating finger followers or with a need to more frequently recharge the on-board bottle supplying the pneumatic spring valve train. Mum’s the word, but now we see the riders working the brakes very hard to compensate for lack of straightaway performance.
Where was Mir in the second race, after leading the first? “I felt great all weekend and in the first race I felt I could win for sure. But in the restart I had to go out on the used tire.”
He didn’t have another left, so it was very hard to hold off the other riders. Miller, on the other hand, had new softs to mount front and rear. It all comes down to what is left in each rider’s tire allocation after practice and qualifying.
Andrea Dovizioso won last Sunday’s race on this track where Ducati has had so many successes, so where was he today? Finishing fifth and only three points behind series leader Quartararo, he said, “…Today I started the race thinking I was very fast and I found myself running slower than most of the riders.”
Trying to understand the mysterious nature of Michelin’s 2020 rear tire, Dovi said, “The first point is that the new tire is causing problems for everyone. We had already complained about it in the winter. Now the others are doing it too.
“It is not normal for such different things to happen in two consecutive races on the same track.”
As so often, Dovi provided information useful in understanding other developments. “The Suzuki is so good in the middle of the corner,” he said, “and they have become better at braking, so now they are very similar to us on the brakes. Their acceleration is not as good as ours but they can exit (from corners) with more speed, and when you exit with more speed you don’t have to use the rear tire so much, because you don’t have to pick up the bike and use maximum throttle because you’ve made the speed (already) in the middle of the corner, so you use the tire a bit less, which is why Mir and Álex Rins are so good at the end of races.”
The Ducatis, he noted, accelerate fast but catching up to the Suzuki head start doesn’t happen until mid-straight.
“They can be fast and more consistent than anybody.”
There is another reason for Yamahas to have heat problems with their equipment (brakes, tires, engine) and that is their now-urgent need to draft faster bikes when possible. That forces them to operate much of the time in the shimmering mass of hot air that streams behind these very powerful bikes. From the especially hot races at Jerez and Brno we remember riders saying they suffered greatly from the heat of bikes ahead. And for some time—not just in this season—riders have observed front tire pressure rising to performance-sapping level during drafting.
Yamaha has a long policy of building engines more for range than for top speed, but the riders no longer find this an advantage. Also, it is harder to make high-rpm power from an inline-four than from a V-4 because of what I shall call “Ishikawa’s Law.” That is because their extra length makes them vulnerable to serious torsional vibration. V-4 cranks derive greater stiffness and stability from their shorter length. Crankshaft torsional oscillations are transmitted to the camshafts, whose resulting unsmooth rotation makes accurate valve control more difficult. Special measures can deal with this but they add weight and require thorough development.
For years it was Honda versus Yamaha, but first Ducati, then Suzuki, and now KTM raised their game, pushing Yamaha riders down the finish orders. Time for change?
I am tempted to speculate that the heat of close drafting may be a contributing cause of the now-you-see-it, now-you-don’t problems with rear tires. Dorna has worked very hard to achieve the present level of machine and rider parity in MotoGP. It educates riders through national series and then via Moto3 and Moto2, to arrive in MotoGP fully familiar with all the tracks and as battle-hardened veterans. And by providing, through the supply of factory bikes of previous years to satellite teams, that every one of these well-schooled riders is aboard a fully engineered racebike.
Here is the list of how many riders were lapping within a second of the top man in this weekend’s practice:
- FP1 20
- FP2 14
- FP3 19
- FP4 18
Many of the riders have remarked on this unusually competitive field. No doubt multiplying Dorna’s efforts, the running of this second race on the Spielberg circuit a week later gave every team the opportunity to further refine its setup and correct previous mistakes.
What is the result of very close competition? Sanctioning bodies seek it for commercial reasons—it makes racing exciting. But a downside is that drafting groups form, from which only an exceptionally powerful bike can escape. We saw this at Daytona in the 600 Supersport class years ago. If you are tail-end Charlie in a group of five MotoGP bikes, you are on the receiving end of roughly one thousand “heat horsepower”—a plume from exhaust pipes and heat exchangers representing the output of a thousand kitchen toasters. The coolest place to be is up front, making it doubly important to get away at the start in the lead group. No telling what all that heat will do to you and your equipment if you are trapped downfield, fighting through a close mass of bikes.
In practice and qualifying, bikes are typically not in tight drafting groups, so tires might operate more normally then. But once the race starts (and poor Viñales once again discovers that the same setup that produced hot laps in practice can act diabolically otherwise in close competition) situations arise in which certain bikes begin to suffer from heat-related tire problems.
The above is pure speculation on my part, but it seems to fit many of the facts. We know that close drafting can send front tire, brake, and rider temperatures into the red, and we know that tire behavior in this series is often mysteriously different between practice and race.
Now the riders and teams get two weeks off before Misano.