One of the best ways of avoiding disappointments is to lower your expectations. Set the bar low enough, and it becomes almost impossible for reality slip below it. That has been the strategy adopted by Maverick Viñales recently, and with good reason: Yamaha's run of form recently has been pretty dismal. No podiums for four races, their longest run off the box since 2007. No victory for 23 straight races, the worst losing streak in their entire history in the premier class.

"I feel more positive about myself, but the expectations are the same," Viñales said on Thursday. "I have zero expectations. I want to just enjoy riding and see if we can take something positive from this weekend." It was a message which he repeated on Friday. "As I said, I don't want to make any expectations. I just want to go riding, enjoy."

There had been plenty for Viñales to enjoy. The Movistar Yamaha rider's expectations may have been set low, but he far exceeded them. In the morning, Viñales was fastest, with his teammate Valentino Rossi in second. In the afternoon, Viñales missed out on the top spot by three hundredths of a second, but Andrea Dovizioso only beat Viñales by putting on a fresh set of soft tires. Viñales had been circulating on hard tires, and lapping consistently in the low 1'31s.

Pundits proved wrong again

Everyone had written off Yamaha's chances before they even arrived in Buriram. Why would Yamaha succeed in Thailand when they had failed at just about every other circuit on the calendar? Yet here we are: Maverick Viñales is not just quick over a single lap, he is fast no matter what the conditions. And Valentino Rossi and Johann Zarco are both in the top ten, and provisionally through to Q2. At Aragon, no Yamahas made it through.

What happened to cause such a turnaround? "We don’t know," Valentino Rossi said. "You go on the track and it looks like the bike has more grip, so you can push more. Aragon was very difficult, but why? I don’t know. The problem is that we don’t know! Also Yamaha don’t know!"

Maverick Viñales had a theory or two. "It's a surprise, but we tried some things that we should have tried many months ago," the young Spaniard said. They had made some big changes to the weight distribution. "We changed the weight distribution a bit, and because I'm quite a light rider, we changed it a bit and it was better. It was very important today to improve a little bit the braking and a little bit the acceleration, and finally we did it. So it's important this test, also for 2019. I'm actually happy, pleased with the result of today, and let's see tomorrow. I am going from day to day, from practice to practice."

The tires had helped too. The harder rubber had worked better for him, Viñales explained. "They have much more grip with the H, and that permits the bike to go a bit better."

Muddying the waters

But being fast at one track, slow at another was not conducive to nailing down the underlying issues with the Yamaha. "The situation is a bit difficult because at the end the bike is the same, but today we suffer less, so it's better," Valentino Rossi said. "For some reason we have a lot of difference between the good tracks and the bad tracks. And it's like we suffer more compared to the other bikes. The other bikes are more balanced, always the same."

One thing which was different on Valentino Rossi's bike was new aerodynamic package. The winglets which grace the front of the Yamaha M1 have been split and doubled, providing a slightly different surface area, presumably with the aim of reducing wheelie, and therefore allowing the bike to be rebalanced in pursuit of more rear grip.

It hasn't made much difference, according to the Italian. "I tried the cowling and usually you have a little bit better for the wheelie, but sincerely I don’t know if I will continue to use because it's very, very similar to the other one," Rossi said. If Yamaha are looking for more acceleration, then this is not the magic bullet they may have been looking for. But in MotoGP, as we have seen so many other times before, there are no magic bullets.

Double down

While Yamaha had a decent start to the Thai GP, Jorge Lorenzo's weekend started as badly as his Aragon race had finished. Lorenzo finished FP1 in seventeenth place, and looked to be continuing the trend started during the test in February. Things were looking up in the afternoon, Lorenzo running in seventh spot, when the rear wheel of his Ducati Desmosedici GP18 locked up going into Turn 3, and spat Lorenzo off. It was his second huge highside in two weeks.

Though he was stretchered off, and the session red flagged while the marshals cleaned the track, Lorenzo was lucky to escape without serious injury. His first concern had been his already injured foot, and the toe he dislocated in the crash at Aragon, trying to open his boot in the gravel trap as he was helped onto a stretcher. But after examination in the medical center, then another at a local hospital, he was left only with a major contusion on his right arm, a very sore wrist, and more pain in his foot.

"Looking at the crash obviously I could be much worse now," Lorenzo said after he returned to the track later on Friday. "I could be much more injured, or I could have injured another part [of my body] that wasn’t injured, or made the foot injured. I’m not 100 percent sure, but I’m nearly 100 percent that I don’t have anything broken. So that's a very good sign. I’ve been very lucky for that because the crash was nasty. At this moment I am quite quiet because I know that was not my fault. I was a little bit worried to have the fall because I was thinking that I was injured and maybe this caused a new crash. But it was completely not my fault because there was a technical problem of the bike. This caused the crash."

Omertà

Lorenzo refused to say anything about the cause of the crash. "I cannot tell you so many details," he said. "You better ask Gigi and maybe he can tell you more." Ducati Corse boss Gigi Dall'Igna managed to avoid the media, a skill he has mastered, but team manager Davide Tardozzi spoke to the media. Although Tardozzi is usually a straight talker, he has also managed the art of obfuscation when he wants to keep his cards close to his chest. "We are analyzing the moment quite deeply in this moment," he said. "We don’t know if we can say something more in the future but we want to avoid any discussion about Jorge’s fault."

If the crash wasn't caused by a mistake by Lorenzo – and it is clear from the footage that Lorenzo was nothing more than a passenger throughout the entire experience – what did cause it? Tardozzi waved off any idea of it being either an engine or an electronics problem. "No, we don’t want to talk about it and we are still analyzing it," he said. At the same time, he precluded any chance of a recurrence. "We are absolutely not worried about this problem and we are sure it will never happen again." If Ducati were still analyzing the issue, then how could they know that it cannot happen again?

Ducati may still be analyzing the issue, but it is almost certain they know what happened. Once Lorenzo's bike returned to the pits, the engineers would have pulled the data off the bike, and seen the precise chain of events. Of course, that wouldn't have pinpointed why it happened, but it would have given them a clear indication of what might have caused the error.

Finding the cause

Watching the replay multiple times, which included footage from onboard, it's clear that there was a problem with the rear. Lorenzo brakes and shifts down through the gears to prepare the entry of the corner, and starts to tip in as normal. As he leans the bike over to take the corner, the engine note suddenly drops fiercely, and from onboard, you can hear the screech of the rear tire as the wheel locks up.

You can see the rear wheel lock up in the slow motion footage as well. If you cycle through the frames as the rear of Lorenzo's bike comes round on him, you can see the spokes of the rear wheel are stationary. The rear wheel is no longer moving.

What could have caused that? Two, perhaps three things. First, the rear brake could have locked on, because of some malfunction of the brake system. Second, the engine could have locked up due to a mechanical problem, and locked the rear wheel. Third, the engine braking system malfunctioned, and caused the rear to lock.

A malfunction of the engine braking system seems the least likely explanation, as that would normally cause the rear to slide, but not lock up. That leaves either a brake problem, caused by either a parts failure, or the faulty assembly or adjustment of the system, or an engine or gearbox locking up. Modern four stroke engines tend not to seize, though it is not unknown.

If I had to guess, I would suspect it was either a brake system failure, possibly related to the thumb-operated rear brake, which Lorenzo would have been using on the way into Turn 3, a right hander. Or it could be a gearbox failure, the seamless gearbox locking up in first, for some reason.

All that is conjecture and speculation, rather than established fact. We may find out what the real issue was, but this is MotoGP, and a factory team, and Ducati. All three of those factors tend toward secrecy, rather than openness, so we will probably never get a public explanation of the facts.

Punishing heat

Conditions were tough out on track, even for riders who didn't crash – and there were a few who went up the road, the fast Turn 4 being a particular favorite spot. The humidity is much worse than at Sepang, so even though the temperature is similar to Malaysia, the heat feels worse, the riders said. Cal Crutchlow explained that the layout of the track didn't help. " I don't think Sepang is as bad as here, because you have two straights. Here, it looks like a straight, but we're fighting the wheelie so much and we're not going straight, that in the end, it makes it more hard work than Sepang," the LCR Honda rider said.

Crutchlow was keen to point out that he was not complaining about his job. "Don't get me wrong, I love riding in the heat, and I love riding a motorbike, and it sounds like we're all complaining," he said. "So to people at home, they'll all think we're complaining about riding a bike in the sun. But when our heart rates are 190ish, riding round …" Riding motorcycles as fast as they can go is already a physical challenge. Riding them in punishing heat and humidity takes that challenge to a whole new level.

Crutchlow also explained why the data from the test was less useful than it might appear. The development of the bikes in the first 14 races of the year meant they arrived at Buriram with a very different baseline to the one they left with back in February. The bikes had moved on, and the teams had a much better understanding of how to get the best from them. "I've tried two different bikes," Crutchlow said. "One that I tested at the start of the year here, so that sort of setting, and then we tried our latest race setting, and I prefer my latest bike a little bit, so that's quite good. It's positive to see that we're going in the right direction."

Heat-resistant tires, less grip

The fact that Michelin had brought a new tire to the race, one capable of coping with the heat for the entire race, also made the data from the test more difficult to use. "I expected this modification by Michelin because in the test no tire can make 25 laps," Valentino Rossi said. "Not just us, for everybody. And the lap time was a lot faster, but the tire after 10, 12 laps started to lose parts. So it was not possible to race with those tires. So like happened in other tracks, where it's very demanding for the rear, like Austria, they bring a tire that is more hard. So you have less performance, it's a bit more difficult to ride, but can make all the race."

That rear tire was costing Andrea Dovizioso performance, despite the fact the Italian was fastest. "We have a different tire and the grip is less," the factory Ducati rider said. "This is normal, because the tire we used in the test, we couldn’t (use) in the race. They changed the tire and the lap time is lower at the moment. I expected to be a bit more competitive this morning and we were struggling. In the afternoon we did a step and I’m happy about that but still I’m fighting on the track – I’m not smooth – and the grip is very low for everybody."

They were still figuring out the best setup for the track, Dovizioso said. The first part of the track suits the Ducati, but the second half, is much more difficult. "I'm moving too much in splits three and four," Dovizioso said. "The [tire] consumption is quite high at the moment for everybody, so still there is a big confusion for everybody. We need to continue to work, not a lap of laps on the tire, and Maverick did the lap time on the hard tire, so still it is not so easy to understand the situation."

Making the soft last

While Viñales set his best time on the hard rear – and in a longish run of 8 laps – Marc Márquez spent his afternoon on a single soft tire. The Repsol Honda rider ended FP2 as fourth fastest, but he was less than a tenth behind Dovizioso in first. After his success in racing the soft rear at Aragon, Márquez was assessing the life of the soft tire at Buriram as well. It held up pretty well: the Spaniard put 23 laps on the soft rear tire, most of which were in the mid to low 1'31s. His final lap was a 1'32.4, which should be competitive at the end of a race.

That might be a little too much to ask of the soft rear, however. When he tried to do a practice start at the end of FP2, the rear tire spun up severely, smoking off the line. Spectacular it might have been, but fast it was not.

The different rear tire was what Márquez had spent his time working on, he said. "In the test we had another rear tire, but now it works in a different way and we are starting to adapt our setup to the rear tire. It was difficult, but at the moment we are working in a good way and the track is good. When I was riding I feel quite good."

But Márquez, like Crutchlow, felt that much had changed since the test, making comparisons hard to make. "The test we did in the winter time was another one and the changes we did during the season were in one direction. Maybe I am not strong like at the test in one lap, but I am stronger on the race pace, so we started with the season base." If Márquez is this strong on an old soft tire, that should give his rivals cause for concern.

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