• INSIGHT: Chinese Grand Prix Debrief: Your Questions Answered

Hundreds of you sent in questions about the dramatic Chinese Grand Prix, so we grabbed Chief Strategist James Vowles to answer a few of them...

Chan Zewei on Facebook asked:

-  What was the issue with the car on Saturday and Sunday? On Friday it looked all good, but it all changed on Quali and race day.

James Vowles: "This mirrors a lot of the analysis we did internally. We agree, on Friday the car looked good, in the hunt for pole position and the race win really, based on Friday performance.

"Saturday, the track cooled down. Friday was around 20 degrees, Saturday was around 15 degrees. It's a small drop in the grand scheme of things, but for us with the tyres, that makes a very significant difference. As we went into Sunday, the track went up to 40 degrees.

"These are very big orders of magnitude shifts in how the tyres work and behave. The other change was that on Friday, it was very windy and blustery, with a head wind on the back straight down into Turn 14 - that's the long straight into the tight right-hand hairpin.

"On Saturday, that had turned into a tail wind into Turn 14 and it changes the dynamic of how the car behaves under braking and under corner entry phase.

"So, you put those two things together and you have very different circumstances you are dealing with between Friday and Saturday, and then Saturday to Sunday."

Siddharth Desai sent in this question on Facebook:

-  Why is the operating window of Mercedes so narrow that it can fight to its full potential only in certain conditions as opposed to Ferrari who on average seem to be surpassing Mercedes whether in cold or warm conditions?

JV: "It's a question we are going through in detail here. If we wind back and take a look at some of the races. In Melbourne, we were able to get the car working on the tyres. In Q3, we set a time that was extremely fast with Lewis.

"If we go forward to Bahrain, the Medium tyre looked to work very well on our car and the degradation on the SuperSoft looked good too. So, there are little vignettes of information where we have been able to get it to work.

"Again, if we go to the Chinese Grand Prix, in Q2 we ran the Soft tyre and did a 1m31.9s with Lewis and that would've put us in contention for fifth place on the grid, on the Soft. You get this evidence of the tyres working and conversely, the same for Ferrari.

"In Melbourne they weren't quite there and on the SuperSoft in Bahrain, they were just outside the range and degrading too much and were a little slower than us on the Mediums. So, it's a window that all teams have to try and operate with. It looked like Ferrari in the cold and very warm conditions of China were faster than us.

"There's several effects going on here. The way the tyres work is they are very sensitive to temperature on the front and the rear, and you need all four tyres working roughly at the right temperature at every single corner of the track.

"Some corners, when they are tight and twisty, you generate a lot of temperature. Other corners, like the back end of the straight into Turn 14, you cool the tyres right down.

"You need a car that is able to work the tyres in a consistent manner and all teams are working their hardest to try and achieve that. As you can imagine, it's difficult to get it all coming together at once.

"Then, the second question. Ferrari and Red Bull are fierce opponents, World Champions developing the car and working day and night tirelessly to beat us.

"We are doing the same but it's an arms race of who can develop their car the fastest and who can produce the fastest car.

"What we can't ignore at this point in time is Ferrari had a faster car than us in Shanghai. So, it is our duty and job to keep working tirelessly to go to Baku and do our best to fight back against them."

Manish (@Manish_Ava) got in touch on Twitter to ask:

-  Are tyre's having a bigger impact this F1 2018 season? I don't think over the past years we saw such massive performance gap at the end of a race just due to old tyres.

JV: "Yes, I think the tyres are having an impact this year. But, more so than that, there's a second aspect as well. You have three teams - Mercedes, Ferrari and Red Bull - that, depending on what race and track it is, are all able to have differing levels of performance to each other.

"In Melbourne we were very fast on both compounds. In the case of Bahrain, Ferrari were very fast on the SuperSoft but had more degradation. And in China, Red Bull were extraordinarily fast on the Soft tyre. What that is creating is different cars with differing levels of performance, depending on the track temperature, conditions and which tyre is fitted to the car.

"Pirelli have created compounds that provide multiple different strategy options on the table. In the case of Bahrain, we went for a one-stop and Ferrari were going for two, but they managed to hold on to the end of the race on the Soft. In China, Red Bull came through the field using the Safety Car to the best avail, fitting the Soft tyre.

"In Melbourne, you saw the field really only using the one-stop because there weren't many other tactical options. But, what we have this year is more overtaking and more difference, and ultimately it's creating racing all the time and enough for us to be thinking about all the way through the race."

Israr (@israrahmedkhan5) asked on Twitter:

-  Can you please explain the undercut of Bottas on Seb? Seb had 2sec lead when Bottas pitted?

JV: "We were 3.3 seconds behind Sebastian before we came into the pit lane, in order to execute the undercut. A few things came towards us perfectly, all at the same time. The first was that our pit stop was incredible.

"In this new era, we did a 1.83 second time based on our traffic light system. Since Austin 2016, with the smaller tyres and wheels, we haven't done times around that.

"Sebastian's stop was slower, around nine tenths slower if you measure the total pit lane time. Already you have eaten into that margin. Valtteri's out lap was extraordinary.

"We have a number of messages we gave to Valtteri so he knew what he needed to do, and it was like a Qualifying lap. He executed it perfectly and didn't make any mistakes. So, that contributed to a couple of seconds gained.

"The final element is on the in-lap you can see Sebastian struggling on those old Soft tyres. They were still in a good state, not completely gone, but they were degraded and you can see a few tenths lost there.

"All of that came together beautifully to allow Valtteri to come out around seven tenths ahead of Sebastian."

Vineet Agarwal commented on Instagram asking:

-  Was everything going according to plan before Gasly and Hartley collided?

JV: "In answer, fundamentally yes. It was going as well as we could've hoped it to. The undercut was successful, Valtteri was managing the position, you saw Ferrari had Kimi out in front and Valtteri had to do an exceptional manoeuvre around the outside of Turn 2 to get ahead.

"That's the point where the plan had potential for failure, because it allowed Sebastian to close back up behind. But, we were confident the Medium tyre from that point would make it to the end, Sebastian was behind us and the Red Bulls or anyone else going for a two-stop would've lost over 20 seconds of race time. So, it was within our control."

Christian Lordinet asked on Facebook:

-  Where was Bottas exactly on the track yesterday when the Safety Car came out?

JV: "Valtteri had just crossed the Safety Car 1 line. Just to explain that, there are two very important lines on track around the pit lane. Safety Car 1 line is where the pit entry is located, and Safety Car 2 line is where the pit exit is located and the two streams of traffic - those on track and those exiting the pit lane - merge together.

"Valtteri was around 10 metres ahead of that Safety Car 1 line and the significance of that means he couldn't get into the pit lane, you are physically past the last point on track where you can cross into the pit entry.

"The reality behind that was he had no other option but to continue round and catch the Safety Car as it exited pit lane."

Chris Evans (@TnMChris) on Twitter had the following query:

-   Was there time to call Lewis into the pits when the safety car was called?

JV: "The simple and short answer is yes. In fact, more so proven by Verstappen just ahead and Ricciardo just behind making it into the pit lane. The question is, why didn't we do it?

"The situation across the race at that point was that cars weren't really overtaking, even when there was a difference in compounds between them. On stint one, you had a mixture of cars on the Softs and UltraSoft and no-one was overtaking each other.

"For us, we had Kimi in front on Softs, so no difference between the two cars and we couldn't even get close. The same with Valtteri at the front relative to Sebastian - but those were the same tyres.

"Verstappen was on the UltraSoft tyre, which was sensitive and difficult - but neither Kimi nor Lewis could make inroads into him. So, on a track like that, the performance difference between compounds wasn't working out.

"With Lewis, under that Safety Car condition, we always review how many positions we could potentially gain or may lose. What would we have gained? With Verstappen ahead, we knew there was a chance that he would come in if there was a Safety Car and, if that happened, it would put Lewis up into a podium position if we could take the Medium to the end of the race and defend from the cars behind us.

"The Medium on our car was working very, very well and indeed we knew that you could do 40 laps on it, which is what you saw with Valtteri. That tyre was still working at the end of the race. The first question is whether a 10-lap old Medium going to suffer?

"The next question is how many positions are we going to lose behind us? We knew Ricciardo was in our window so if he didn't stop we'd drop behind him. We then had Kimi, who stayed out very long and was back in what we call the 'Safety Car window' for Lewis.

"This means it would've been very marginal if Lewis was going to come out ahead or behind Kimi. Both Red Bulls took that opportunity. Ricciardo came out behind Kimi and Verstappen was ahead.

"With Lewis, we also knew if we stopped under the Safety Car we'd always be behind Verstappen. It was a decision that when we laid out all the facts on the table, we didn't believe, based on the earlier evidence, that there would be enough performance differential for a Soft to overtake a Medium, even one that's 10 laps old.

"The reality of the situation, everyone saw what happened. Both Red Bulls were extraordinarily quick on that Soft tyre and were able to scythe through the field."

Ben (@BenBelcher) tweeted us asking:

-  When a decision has to be made so quickly as was with Lewis coming to box under the Safety Car, is there time to run the computer simulations or does the decision have to be made by a human on the pit wall?

JV: "We have simulations running in the background but they are looking one to two laps ahead. So, you don't have to run simulations instantaneously when the Safety Car is deployed.

"So, you rely on simulations that were running 60 seconds or two minutes ago, to allow you to understand what the pros and cons are. There are humans who make the decision at the end of it.

"The reality behind that is the computer simulations are a system that allow us to try and make as informed decisions as we can do, but ultimately we rely on our knowledge and our experience supplemented by the computer systems in order to make the best decisions possible."

RNB44 on Twitter asked:

-  I noticed Lewis' Qualifying time was same as last year's. Why do you think the car was not quicker than last year's quali time?

JV: "The car itself, we are confident is faster than the 2017 car. You have seen evidence already of that across multiple other tracks - Melbourne and Barcelona at winter testing being examples.

"What you are seeing is a shift in environmental factors for a track. As you go to one track and it becomes windy, or not windy, cold or hot, you can see up to a second swing in lap times because of all of those environmental factors.

"In Shanghai, with conditions that were 15 degrees, which is really colder than we'd ever usually run in, you are seeing the car isn't quite working in those conditions. And that's why the lap time mirrored the one of last year."