Nicki Shields looks at the different gearing solutions the Formula E teams have introduced for season two...

The Beijing opener saw the first glimpse of what impact the new rule changes will have on the championship. For those of you late to the party, one of the major changes allows teams to modify the powertrain from the battery backwards, including the motor, gearbox, inverter and rear suspension.

Although the teams were testing their new cars at Donington Park, it was difficult to read too much into their performance due to the nature of the track - it’s a smooth, fast, undulating, purpose-built race track - a far cry from the majority of the tight and twisty street circuits that make up the Formula E calendar.

The Beijing track is the longest on the calendar at 3.4km and the characteristic long straights, slow chicanes, and sharp ninety-degree turns are unique to this course, but it is a street circuit by nature. So 10,000 miles flown, 20 interviews filmed, and one race complete. What can we learn about the new cars?

Gears

The most obvious change is the gearing. Each team is running with their own unique gear strategy, some with the original five sequential gears and single motor, while others are implementing the total opposite, a single gear with twin motors. Then there are also those somewhere in between, who perhaps thought taking the middle ground would be the safest option. Despite the teams being rather protective of their new powertrains, this is what we could deduce from Beijing:

TEAM GEARS MOTOR NEXTEV TCR 1 Twin DS Virgin Racing 1 Twin RENAULT e.dams 2 Single Abt Schaeffler Audi Sport 3 Single DRAGON Racing & Venturi 4 Single Trulli 4 Single Mahindra Racing 4 Single Team Aguri 5 Single Andretti 5 Single

So, why does each team have a different strategic thought process? And more importantly which strategy is going to win races? There are different considerations for each, but a pay off between efficiency and weight seems to be key.

The original Spark-Renault SRT_01E from season one has five sequential gears, with a Hewland gearbox and McLaren motor modified from the P1 sportscar. The gears allow the motor to be as efficient as possible by working in power bands to match the revs and reach the zenith of the cars potential on bends, chicanes and straights - effectively maxing out at every point on a twisting street circuit. But every time a driver shifts up or down a gear, there is a drop in power for a few milliseconds; the car almost cuts out momentarily. This is inefficient, as the regeneration of the battery also stops. And this is a championship based around the battle of speed versus energy, where conserving energy matters.

So, the fewer the gears, the more efficient the car? Up to a point. In our road cars, the majority of EVs do not have gears. With 100 per cent torque, a single gear does the job. But in a racing environment, especially off the start line, things are a little different. It’s possible the cars can’t get the optimum torque at the start without a gear. So how do you maximise efficiency throughout the race, whilst maintaining maximum acceleration off the start? Let’s find out what the results from Beijing showed.

Renault e.dams

Renault e.dams nailed it. It was an outstanding performance from Sebastien Buemi, who in addition to scoring the maximum points available, (3 for pole, 2 for fastest lap and 25 for the win, the first time this has been done in the championship) he also finished 11 seconds ahead of Lucas di Grassi.

Renault has provided Buemi and Prost with what appears to be championship-winning car. So why is it so much fastest than the rest?

- The gear set-up they have chosen is based on two gears, a starter gear and then a single race gear. So they have minimised any inefficiencies from shifting up and down through the gears and maximise the power off the start.

- It’s light, it’s one of two cars on the grid that hits the minimum weight requirement of 888kg, alongside ABT Schaeffler Audi Sport. Other teams like Venturi and Dragon are slightly over the mark, whilst DS Virgin is one of the heaviest and NEXTEV needs to go on the Atkins diet. So how have Renault e.dams achieved this slender toned body? They have developed a carbon fibre gearbox casing.

- Money and man power help too. Renault heavily invested in the car and technology, rumoured to be over an eight figure value (USD). And also Vincent Gaillardot is the man behind the car - he has 10 years’ experience running electrical and electronics projects at Renault, including Formula 1 and the partnership with Formula E on the season one car.

NEXTEV TCR

NEXTEV TCR (as well as DS Virgin Racing) chose the single gear, twin motor solution. The single gear reduces the inefficiencies of gear changes, but the twin motors are bigger and heavier, especially in the case of NEXTEV TCR. The additional weight (30kg plus, possibly as much as 50kg but this is unconfirmed) will take effect on chassis balance. The Formula E car already has a balance of 61 per cent to the rear, so with this added weight it’s going to really effect the competitiveness and efficiency of the car.

And it showed in the results. Oliver Turvey managed a very respectable sixth, but did benefit from the Full Course Yellow. Nelson Piquet Jr had a disastrous weekend crashing into the pit exit during practice, believed to be caused by a faulty throttle sensor, and then during the race his car stopped on track. This team has its work cut out (as Nelson kindly reminded them after the race).

Abt Schaeffler Audi Sport

With three gears, ABT Schaeffler is somewhere in the middle and it paid off. Enough pace to secure him a spot in the Super Pole shoot-out, and qualify in third place and enough power and efficiency to lead to a podium finish for Lucas di Grassi. With one of the lighter cars on the grid, Abt Schaeffler looks strong, although can there be enough improvements in software and strategy to enable them to compete effectively with Renault? It seems unlikely from di Grassi’s seat, (and 11 seconds behind Buemi).

Venturi & DRAGON Racing

After an incredible end to the first season, Dragon had a solid start to season two with Loic Duval and Jerome D’Ambrosio finishing fourth and fifth. Disappointed not to be on the podium but proof they have the pace to compete amongst the top teams again.

Dragon is the first customer team, purchasing their powertrain from Venturi, and it beat its immediate competition, with Venturi’s Stephane Sarrazin finishing in ninth. In terms of the hardware, the Venturi and Dragon car is exactly the same, but the software and strategy is different. They displayed solid energy management and according to Jay Penske, the team didn’t undergo many changes, keeping the core personnel the same. Plus there is a lot to be said for the healthy but very close competition between Duval and D’Ambrosio.

Mahindra Racing

Behind the Mahindra Racing team are some strong credentials. They are owned by Mahindra, a $10 billion automotive manufacturer in India and also Mahindra Reva Electric Vehicles who supply EVs in 26 different countries. Its works team is Campos Racing (the team behind the championship-winning car at NEXTEV TCR) so it should be a strong outfit. With a four-gear solution provided by Hewland and motor from McLaren (very similar to the season one powertrain) and plenty of hard work over the summer spent developing its software, Mahindra has finally delivered. After a great performance from Nick Heidfeld, Beijing delivered their first podium finish. The hardware is an evolution of the season one car, however, the key for Mahindra seems to have been the investment in their software with partner McLaren.

The unpredictable nature of Formula E racing is a quality that has been popular. The new powertrain rules will keep the pressure on the teams and drivers to work really hard, whilst keep all of us guessing who will be biggest contenders come the end of season two.