McLaren may have raised some eyebrows with the step change in its car design for this season, but technical chiefs are adamant it was an essential move if it is to gun for Formula 1 title glory this year.

With the rules not changing dramatically for 2013, and teams already devoting much resource to the radical 2014 overhaul, it had been widely expected that the new cars would be mere evolutions of last year's designs.

McLaren has gone much further than that, however. It was reworked its concept in a wide range of areas, including switching to pull-rod suspension, increasing the height of its chassis so it now needs a 'vanity' panel' for a stepped nose, and being ultra-aggressive with the bodywork around the rear.

Although such work may be a bold move with 2014 on the horizon, the team has said that such an effort was vital if the team was to be able to keep up a good enough development rate throughout the forthcoming campaign.

When asked by AUTOSPORT about the thinking behind such an aggressive push with its car, McLaren engineering director Tim Goss said that there was a fear last year's MP4-27 concept was reaching a development ceiling.

"We looked at our performance during last season, in the stages where we were laying down the foundations of this car, and looked at where we thought we would get to in terms of our development rate if we just kept continuing with developing the same car," he said. "We realised we actually needed to make a larger step.

"So in defining the architecture of this car, the philosophy was very much to give ourselves the scope to further exploit the area of the cars that we knew would generate performance.

"We understand how to get the most out of these rules, and we demonstrated that last season under these rules with the quickest car at the beginning of the year and the end of the year.

"But, we decided that we need to give ourselves a bit more freedom and, as a result of that, we have reworked the car from front to back. That has allowed us that bit more freedom to push the areas of the car that we know respond."

Pull-rod front suspension

One of the boldest departures for McLaren is in switching from a push-rod to pull-rod layout with its front suspension, a route that Ferrari went down last season.

Goss insisted that its change was not simply the result of it copying Ferrari's lead, but of doing a lot of work into evaluating the benefits and drawbacks of such a design.

"What convinced us was actually a lot of research," he said. "When you see something new on a car, you always think, why have they done that?

"In F1, it is possible to copy someone else's concept, but invariably they don't work. What you have to do is get a fundamental understanding of why.

"So we looked at it and initially we thought exactly that - why? But after some time and some work we understood how it could benefit our car and certainly what we are trying to achieve with the car.

"We found benefits in terms of aerodynamics, which overcome the kinematic and structural negatives of doing more extreme anhedral suspension."

Exhaust concept

One area where McLaren has stuck to its guns, however, is in its exhaust concept, which is a different solution to the Red Bull style.

This year, McLaren has pushed things much further, dramatically cutting away the bodywork at the rear of the car to try and optimise airflow for both car performance and exhausts.

"It is playing the tunes on the aerodynamics," said Goss. "While trying to achieve one thing with the exhaust, you have to make sure when the exhaust gases are not flowing that the rear end of the car is still performing properly.

"So we have pushed things further. That is our philosophy on this car - to take the things where we know the car responds, push them further and make them more extreme. For us, it was a natural evolution of last year."