Mercedes F1 explains the difference between porpoise and rebound


The two words have generally been interchangeable when used by teams and drivers this year, but Vowles says they are not the same and are generated differently.

Mercedes seemed to overcome its problem with the W13 at the Spanish Grand Prix, but Vowles says the problems are very circuit-specific, with surface smoothness playing a key role.

The rebound problem was exacerbated by the Baku track’s bumpy surface, causing extreme discomfort for the drivers, and especially for Hamilton. The seven-time F1 world champion had a different setup than his teammate, including alternative rear suspension.


“There’s definitely a track-by-track element and it’s a function of how smooth the track is and the layout of the circuit,” Vowles said in a Mercedes video.

“I would say that Baku certainly of the circuits we have had so far is at the worst end and conversely Barcelona probably at the best end.

“So those two circuits will definitely highlight the strengths and weaknesses of the package. But it’s also worth spending a little time explaining porpoise, bouncing, bottoming out — three words that may say a lot with a bit of association that they’re the same thing, but they’re not quite the same thing.”

George Russell, Mercedes W13

Photo By: Steve Etherington/Motorsport Images

Vowles noted that, as the Spanish GP indicated, the team has made progress in controlling the porpoise. But in doing so, and thus being able to run the car lower, rebound has become an issue.

“We definitely had porpoises in the previous races and in Barcelona we didn’t,” he said. “And we’ve put a lot of effort into our package to make sure we did everything we could to figure it out, and I’m sure we’ve taken a step.

“In Barcelona the car was stable, robust and we were able to lower it and that is the key, we managed to create a package where aerodynamically we were able to work much more with it, we were able to work with the set-up and we were able to lower the car in terms of performance of ride height production.

“We now go to Monaco and Baku, what he unfortunately discovered is a second problem that was being masked by the first. I’m sure we’ve made a step up in terms of porpoise, but we clearly have rebounds, and on the outside it looks almost identical, but there’s a subtle difference between the two.”

Vowles said the rebound is simply a function of the car hitting the track: “What’s happening now is the car is lower, as a result of fixing the first problem, but now it hits the platform quite hard, and that’s creating the bounce you see right now.

“Again you try to extract performance by running the car low, but the problem is very different and the bumpier the track, the more clearly it has the effect, which is what we saw in Baku.

“I think what is clear is that we still have a long journey ahead of us to learn everything we need, to be fighting at the front, but perhaps more importantly, you will see the variation in performance along the way as we go. For sure Canada will be very different to Silverstone in terms of the performance of our car.

Vowles admitted the team made life too difficult for its drivers in Baku, while confirming Hamilton will be fit and ready for this weekend’s race in Canada, despite Toto Wolff expressing concern on Sunday about the night.

“I am pleased to report that Lewis is here this morning. [at the Mercedes factory]I spent a few hours with him and he’s fine, he’ll be back in the car in Montreal,” Vowles said.

“He is an elite athlete who will push the limits of his endurance and that of the car and that is what F1 drivers do, that is what makes them exceptional.

“On this occasion, although we pushed the package and our drivers too far, we are putting them in significant discomfort and we just can’t do it again.

“Our drivers are not the only ones suffering, you will see in the media a series of comments from various drivers who are equally upset and in pain. And now we have a responsibility to make sure this doesn’t continue.”

Lewis Hamilton, Mercedes-AMG, in Parc Fermé

Lewis Hamilton, Mercedes-AMG, in Parc Fermé

Photo by: Simon Galloway/Motorsport Images

The team was taken aback by Hamilton’s “cold seat” comment in Baku, but after speaking to his driver, Vowles, said it was a physical problem rather than a mechanical one.

“What happened is that nothing had really changed in the car, it just seems that after the amount of hits it took in the back from the rebounds, fundamentally it had a numbness that set in and it seems that the cold was a response to that.

“There was nothing colder about the car, it was just a response to the amount of drag and pain that he had been through in the race.

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