F1: Webber's lowly Shanghai grid slot may prove inspired

Throughout today's qualifying session for tomorrow's race, one of the most noticeable features of the Shanghai track - aside from its pseudo-Corkscrew corner sequence and a right-hander with almost oval-circuit style banking - was the rapid accumulation of marbles - the rubber that is shed by tyres and builds up around the track. At points, the clean area looks all-too like the dry line on a wet track. Going off-line will mean hitting the marbles - which are called that because they are small hard balls that severely reduce traction. But in motor racing, the main way that overtaking is done is to go off line.

So the best way to make progress in a race where the track is so dirty is to make sure that you are driving a car that is fast enough to blat past rivals on the straights - because although dust accumulates off line on the straights, it's a lot less likely to cause an accident than overtaking on marbles.

The difference between the hard "prime" tyres and the "option" soft tyres in Shanghai is a little over a second a lap. All cars have to use at least one set of each tyre during the race. The option tyres are very sticky when they are new, then as they heat up they go off a little and then they come back to full performance. Teams do not have enough data on the new tyres to know how many laps they will last in the heat of battle. What they do know is that a car set up for one type performs poorly on the other. In Malaysia, Button was set up for hard tyres, Hamilton for soft. As the race wore on, Button was able to capitalise on longer tyre wear to finish second.

Each driver has three sets of each type of tyre which have to last through qualifying and the race. All the front runners used at least two sets of soft tyres in qualifying. That means that they have been through their first heat cycle - a trick that Vettel used in the Australian Grand Prix in Melbourne.

So how does starting 18th help Webber?

It's a little more complicated that just to do with tyres: the Red Bull team cannot get KERS working properly. They didn't turn it on in Melbourne. In Malaysia, Webber's broke just before the race and Vettel's broke during the race - but came back on from time to time. In this morning's practice session, Webber's KERS broke again. Vettel was able to use his to secure his third pole position in the first three races of this season.

That meant that Webber was down on power on the all important straights by some 90BHP: that's a killer shortage. And so, no matter what he did, Webber was unlikely to do much better than 14th or 15th. And to do that, he would have had to use soft tyres.

Instead, he and his engineers opted to do the best run possible on the hard tyres. That puts him on the dirty side of the track nine rows back. In fact, only Team Lotus, Virgin and HRT are behind him.

Team Lotus use the Red Bull drive train and the same Renault engine as Webber and Vettel. But, although they have KERS fitted as required by the Regulations, they have not developed it sufficiently to be able to use it. They are, therefore, running with a weight penalty and the same power disadvantage as Webber.

In Malaysia, sitting towards the front, Webber was swamped by cars with KERS and shuffled down the grid, losing buckets of places on the way to the first corner.

A simple question arises: why risk being the slow moving car in the middle of a fast moving pack into one of the tightest and most complex series of turns on the F1 calendar? Is it not better to, simply, not be a target, likely to be bumped out of the way and possibly out of the race.

Amongst the slower back markers, Webber will have the chance to be out of the fray.

If he starts on hard tyres, he will lose approximately one second to the front runners - who will be on soft tyres to start hoping to hare away - due to the tyres. He will also lose a little due to KERS. But, as he proved in Malaysia, given a relatively spread out field, he can make up places quickly and with little risk.

There is great debate over whether a one, two or three-stop strategy is the fastest for the race. For Webber, it's a no brainer. He can run the hard tyres for the first one or two laps then, once the field has spread out, he can dash into the pits and change to the softer tyres. His car is much faster than the bottom dozen competitors, even without KERS, and with new soft rubber he will be able to match the pace of the front runners as well as passing half the field in the ten or so laps after his tyre change. That will bring him onto the verge of the points. By then, most of the back markers will be more than 25 seconds behind him - meaning he can do another change and not lose places other than the two or three cars behind him. On new rubber, he will be able to make short work of them and get back to his previous position - and then be in a position to attack the second batch - which is likely to include Ferrari.

When the leaders change to hard tyres - which they will need to do, Webber will have already got the problem of the slower tyres out of the way - and he will be faster.

Strange as it seems, provided the changes are timed correctly, if Webber does a three-stop strategy dumping the hard tyres as soon as possible after the race starts, he stands an excellent chance of being in the top four with Vettel, Button and Hamilton.