Christian Horner explains Mark Webber's problem with starts this season

One of the most striking stats from the JA on F1 Strategy Briefing, supported by UBS, is the start record this season of Mark Webber.

The Red Bull driver had lost 20 places on aggregate off the start line and after he lost five places at the start in Spa many readers have posted questions about this recently.

So we spoke to Red Bull boss Christian Horner and he gave this explanation,

"It's been a culmination of things really, " he said. "The Spa thing was more a calculation on the Renault side really, measuring the amount of torque that was required and Sebastian was within just 100 revs of having exactly the same start as Mark.

"It was one of those things about the engine tying in with the chassis electronics and not having done a start over the weekend because of the wet weather, more grip than expected and an uphill start - all those factors came together.

Another question many fans want to know is how much of this is dictated by the electronic systems on the car and how much is driver operated.

"Well you have two clutches, so the driver will release one lever and then feed in the other," explained Horner. "So how they prepare the clutch on the way to the line is important, the engineers give them instructions on the number of burn-outs they need to do. They rehearse religiously to get the clutch clean - the best it can be for the start.

"Then it's about matching the torque demand from the engine, through the clutch bite point and synchronising that. The drivers have the throttle position which they manage with the foot, then with the clutch he needs to keep his arm light, dumping one lever, feeding in the other one. At the same time he has to use his mirrors to see what's around him.

"It's very easy to overslip the tyres, creating wheel spin. It's easy to underslip, where the engine bogs down and you have a bunny-hop start.

"So it's a very small window that you are operating in.

"Mark's had some good starts, unfortunately the bad starts have been when he's been right up the front."

Team mate Sebastian Vettel in contrast has lost an aggregate four places off the start, including one in Monza where he started on pole and was second at the end of the first sector of the lap. It is one slight weakness in Red Bull's otherwise pretty much optimised game, possibly also linked with its sub-optimal KERS system, which has been reduced for packaging purposes. Not only do they have a fast car, they are also top of the pit stop time league table, for example.

Teams do a lot of work on starts, especially if they aren't working out well, Williams for example was losing a lot of places early in the season and seems to have rectified the problem.

Conversely, teams like Mercedes and Force India have had consistently very strong starts this season.

For a visual explanation of how the clutch levers and bite point adjusters work on an F1 steering wheel, here is a video I shot last season at Team Lotus.

Watch out for the Strategy Briefing for Singapore here on JA on F1 early next week.

Additional reporting: Tom Clarkson