2013 German GP Tech Highlights

The German Grand Prix build up has been dominated by talks of boycotting due to the safety of the Pirelli tyres. Realistically this was never going to happen, but it shows that most drivers are concerned with the behaviour of the tyre as it fails or indeed why it fails in the first place.

Along with all of this uproar some teams have also managed to bring substantial updates to the cars in the space of a week. Let’s see what they’ve got to offer…

But first…

With tyres being the main talking point for this weekend, I thought that I would give you a small insight into why the changes Pirelli have made are important and who it may be advantageous to.

The 2013 tyres supplied by Pirelli have had steel belts the entire season so far. The belt is the part that joins the tread block to the carcass of the tyre. The steel material is heavier, therefore the total minimum weight of the car and driver has been increased this season up to 642kg (up by 2kg from last year). Not only is the steel heavier but it has different mechanical properties.

Steel is a metal and therefore is a good conductor of heat. Due to its characteristics, the type of steel composite Pirelli use retains heat rather than dissipate it. When we see the tyres reach over their operating window it is very difficult for the drivers to bring them back in again. This is mainly caused by the steel belt.

Combine this with the more flexible sidewalls and softer compounds found in this year’s tyres, the whole body of the tyre becomes a fragile unit that is incredibly difficult to manage efficiently.

For the German Grand Prix, Pirelli have supplied a combination of the 2012 and 2013 tyres: ’12 belts (made out of Kevlar) and ’13 compounds, which is the actual tread block and sidewall. The Kevlar belts are able to dissipate heat much more easily therefore tyre heat management is easier for the drivers. This should dramatically reduce the problems Mercedes and Red Bull have been experiencing by overheating the core temperatures and not being able to bring them back down again. This will not favour Ferrari or Lotus as they have so far been struggling to bring the tyres up to the operating window during qualifying, even with the steel belts.

Between the Spanish and British races, Pirelli researched (with the help of Mercedes during the tyre test/tyregate) a new bonding process between the belt and the treadblock of the tyre. The idea behind this new process was to help eliminate a total delamination of the tread from the belt as seen in Bahrain, Malaysia and numerous times in Spain.

To some extent they succeeded…

However, instead of a delamination, drivers experienced what is known as a blowout, which is when the tyre explodes completely rather than the material (in this case the treadblock) failing under load. This happened because the new bonding was so strong that when a failure occurred it took out the whole tyre.

These were understood to be caused by the combination of the weaker, 2013 specification sidewalls and drivers running over the kerbs at high speed. This cut the sidewalls and, combined with the high heat retention from the steel, eventually led to an explosion. These failures all began at the inside shoulder of the tyre suggesting that the drivers were well over the kerbs almost every lap.

We could go into debate about whether drivers could have done anything about it etc. but that’s not what I’m here to tell you…

Overall, the changes that have been made for this weekend should see less or no failures at all, as heat within the core of the tyre is being dissipated more effectively by the Kevlar belt.


Following on from the introduction of the Lotus system in Silverstone, Mercedes brought their Drag Reduction Device (DRD) with them to the Nurburgring. I find it quite interesting that the system from both teams has been perfected enough to be able to run it at a race weekend at a roughly similar time during the season.

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It is also amazing how much the Mercedes system has been changed since its last outing in winter testing. Appearing on only Nico Rosberg’s car, the system now comprises of two inlet points and multiple outlets. The inlets are visible above, with the already seen main opening behind the T-cam and another additional inlet further back.

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Looking at this more closely, the two inlets have separate tunnels running down the back of the engine cover, which appear to join just before it exits upwards and outwards towards the underside of the rear wing. At this join there will be a fluid switch that compromises of rubber valves. This switch will passively change the direction of flow from going out of the horizontal opening beneath the monkey seat winglet to beneath the rear wing.

This is probably incorrect but I am assuming that at lower speeds a large volume of flow simply passes straight through both the main inlet and secondary opening. At higher speeds, flow bleeds off from the secondary opening as it is far smaller (buffeting occurs), changing the pressure delta within the two tunnels at the meeting point and therefore activating the fluid switch.

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After the meeting point the tunnels then split again like the other DRD systems we have seen, resulting in the horizontal outlet, that is fed by airflow at low speeds, and the vertical outlet that flow travels up at high speed, blowing into the underside of the rear wing and stalling the low pressure region.

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What intrigues me most is the outlet on the vertical element. There appear to be two parts to it: the leading section attaches to the underside of the rear wing via two pieces of carbon fibre and a wider outlet. I am unsure if the two pieces that attach to the wing are hollow or not but they don’t appear to have any visible openings in them. The wider outlet is clearly the main part of this element.

Also worth noting is the horizontal opening beneath is split into three sections. This may help bleed off flow more efficiently and could also control how the beam wing/monkey seat combination is utilised at varying speeds.

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Following on from their Silverstone revisions, a new nose was introduced to the W04 during free practice. Much similar to the Ferrari layout, Mercedes have brought forward the pillar mountings to the very front of the nose tip, with the overall pillar having a greater surface area. The height of the nose has also increased, allowing more airflow to travel beneath the chassis and towards the T-tray. The new flap profile and IR sensors remain from Silverstone.


Ferrari continued to carry out testing with their extended exhaust/sidepod profile. Having been run during qualifying and the race in Britain, both F138s had the shorter profile outlets attached for the majority of Friday practice. The team also assessed slightly different front wing designs, with the under-wing strakes varying in length.

Fernando Alonso’s FP1 troubles were caused by ECU issues, which had to be replaced during the session. This meant that all of the electronic systems had to be recalibrated as well.


Only Romain Grosjean had the Lotus DRD available to him, although Kimi Raikkonen used the slimmed bodywork that was brought to Silverstone. Despite the two completely different purposes of the two updates, the two Lotus cars have had very similar pace over the past two races. Perhaps a combination of the two in Hungary will really put them back in the playing field. Time will tell…


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Sauber have been quite quiet when it comes to aerodynamic updates this season, although you could argue the array of rear wings brought to each race over the opening few rounds compromised their development strategy. A small alteration to the shape of the top flap has been installed with a unique rounded tip inboard.

The round tip is interesting because the general theme in this area has been exploiting a sharp edged tip combined with a large area left beneath to the lower flap. This sheds a vortex back along the inside of the front wheel of the car and allows components further downstream to work more effectively. Sauber’s front wing design has been one of interest to engineers up and down the pitlane over recent years, so let’s see if other teams take note of this different approach.

Force India

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Introduced in Britain, Force India have adopted the concept of using small strakes to direct airflow better over elements of the front wing and extracting the best from the under-wing fences. The image above shows how each strake is paired to its respective under-wing fence. These create a very small vortex and energise the outgoing airflow heading for the outside of the front tyre. I thought I would revisit this area as this image is a lot better.

If you have any feedback or constructive criticism, please leave it in the comments section below. It doesn’t take long to say a few words and I would really appreciate it. Thanks!

3 thoughts on “2013 German GP Tech Highlights

  1. Morris Dancer

    Although not a technical chap I also expected Red Bull and Mercedes to benefit from the tyre change. In the race Mercedes seemed to have gone back to their tyre-eating ways, and on race pace the Lotus seemed at least equal and perhaps faster than the Red Bull. All rather perplexing, really.

    Will you be keeping abreast of the tyre test? It seems that may end up playing a critical role in the title races.

    1. thewptformula Post author

      I think the Kevlar belts will have had a positive impact for both teams, but it was the ban on tyre swapping (left to right, not front to rear!) that cost Mercedes badly. The Mercedes tyre degradation wasn’t actually too bad, it was just that the temperatures were a lot higher and the tyre faded away…

      Yes, although unfortunately my parents won’t let me go to one of the test days, which is understandable. It will be very interesting, definitely.

      1. Morris Dancer

        Front to rear swapping would certainly be an innovative approach.

        If that’s the issue then it might suggest (coupled with Mercedes’ ban from the YDT, which they seem to want to try and overturn) the team will suffer for the rest of the season. I wonder if Force India, who also dropped off the pace this time, will also lose some relative performance.

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