Mercedes built its own collision course

The Austrian Grand Prix had a bit of everything, from suspension failures in practice to rain in Q3 with a Force India second on the grid and a McLaren-Honda third, to an eventful race featuring Sebastian Vettel's right-rear tyre failure and resulting crash and a cat-and-mouse game between Lewis Hamilton and Nico Rosberg.

And we had Manor, with Pascal Wehrlein in particular, qualifying 12th and finishing 10th to prove that a small team with a top notch driver can get in among the big boys to score points. But the clash between Rosberg and Hamilton on the last lap was, of course, the main talking point.

Their last collision was in Spain in May - the main difference for the Mercedes mechanics being that at Barcelona they could start packing up early while in Austria they had to stay to the end.

But there is another, more important difference. Crashing on the first lap is a very stupid thing for a driver to do, and involving your team-mate in that is totally unacceptable. In Barcelona, I blamed Hamilton as he was the one who could see what was going on and could have done something about it.

Austria was very different.

With Hamilton on pole and Rosberg sixth on the grid after a gearbox-change penalty, Mercedes was probably looking at another one-two finish with Hamilton easily leading the way. The team, as well as the drivers, played a part in throwing that away.

The different strategies literally set the two drivers on a collision course. Two highly competitive drivers both at similar times in their careers met up on the last lap, one of them struggling on super-softs and the other rapid on the softs. This tyre difference was what led to the incident.

Why? Well, Rosberg pitted on lap 10 to fit soft tyres. At that point, he was more or less committed to a two-stop race. Hamilton pitted on lap 21 to take the soft tyres, so could have stretched it to a one-stop race.

They were now on the same tyre, and Hamilton would either have to catch and pass Rosberg or rely on him stopping a second time.

Vettel's super-soft tyre failure on lap 26, which when you include the three laps in qualifying means that set of tyres had done 29 laps in total, probably made Mercedes think that a one-stop strategy was a bit risky.

Hamilton had closed the gap to almost nothing and then pitted again on lap 54. He took another set of softs so was comfortable to the end of the race.

Rosberg pitted a lap later and fitted a set of super-softs (he had selected four sets of super-softs to Hamilton's three for the Red Bull Ring, and only had one set of the softs), so he maintained the lead because Hamilton ran wide on his outlap and had a slow stop, which cost him time.

By doing what it did, the team put the two drivers into a battle that was very likely to end in tears. After all, you always expect your drivers to do everything they can to win the race, especially when fighting for the world championship. Remember, it was Mercedes that put its drivers in this position.

Mercedes could have put the super-softs onto Rosberg's car at his first stop in the knowledge he would stop again. Then he would have had softs for the run to the flag, and tyre equivalency with Hamilton.

If a team creates a strategic benefit for a driver by putting a different tyre compound on its two cars, it has to suffer the consequences. We heard Hamilton question why Rosberg had the softer tyres fitted and his engineers telling him that his own tyre choice was the best strategy. At that point, they were confident of winning the race. But there are 22 drivers out there and, whoever you are, the other 21 are your enemies - including your team-mate.

So that created the situation where Hamilton passed Rosberg into Turn 2 on the final lap and Rosberg's attempt to hang on led to the collision. There was a feeling of inevitability in this, and ultimately the team was in the position to prevent these circumstances ever arising.

We also heard during the race a warning to Hamilton about suspension loads off the back of a number failures for several teams during the weekend. Such failures are about a combination of the tyre frequency and the frequency that the kerbs put into the suspension.

All the teams have lots of experience with the conventional red and white kerbs, which have a 25mm step approximately every metre. The new kerbs, the red ones that are positioned behind the conventional ones at the Red Bull Ring, have a 50mm step - so twice the height.

At certain speeds, this then sets up a resonance in the suspension. That, combined with the tyre frequency, basically overloads the suspension components in the critical or highly-stressed areas, which then leads to failure.

Pirelli has also been adding pressure to the tyres to help them withstand the loads that the current F1 cars are putting into them. This can also add to the problem as it increases the tyre stiffness, which will move the tyre frequency into a different area.

The kerbs are there to act as track limits and are car destroyers. It is the driver's responsibility to stay away from them at all times.

Teams gather bucketloads of data and that is used to identify the peak loads that every suspension component has to withstand. Let's say for a certain component it is a compression load of 1000kg.

You will then add on a safety factor to that peak load. If you are confident in your data you may multiply that peak load by 1.2, making the component withstand 1200kg before failure. If you are not so confident, you may use 1.5, making it 1500kg before failure.

You hope going into any race that you have covered everything, but when something like Rosberg's rear suspension failure happens you have to react. As we saw, Mercedes did so and very quickly.

The team identified that the failure happened where the top rear wishbone blends down from the stiff outer end into a single leg and wrapped some carbon around the affected area, cooked it off and wrapped it in black tape. Job done.

You may ask why not do this at the design stage? The answer is simple; every component is built to the minimum weight possible, add this amount of extra weight everywhere and the car would be overweight very quickly.

Also, I wouldn't be surprised to find that this same kerb frequency problem led to Vettel's tyre failure. His tyre failed at the intersection of the outer shoulder. Basically, if you move something up and down enough times it will fatigue and fail.

Try it with an old fork or something like that, keep bending it back and forward in the same place and it will break.

Fortunately for Mercedes, the suspension on both cars held up enough in the collision for Hamilton and Rosberg to cross the line. Although for a team to have lost that one-two finish, a one-four will only be some consolation.

The key is the team learns the lessons of this race and doesn't put its drivers on a collision course again.