Some musings on the Chinese Grand Prix

Sunday's Chinese Grand Prix produced one of the most frantic, action-packed races (certainly in the dry) that F1 has seen for many a year. A combination of tyre strategies, KERS, DRS and some good old-fashioned wheel-to-wheel racing kept us guessing right to the very end. There were a couple of intriguing asides to this race that occured, which I will attempt to cover here.

Cycling-style 'echelons' in F1?

DRS appeared, at least in China, to produce a secondary effect alongside its raison d'etre to produce more overtaking. Around the middle of the first stint it was apparent that the field had broken up into distinct packs, that were not necessarily due to slower cars being out of position holding up a train of rivals behind. 

Here is what I believe is happening. After two laps the DRS system is activated. By this point, the natural field spread of the pack of cars means that each driver is spaced roughly around a second or so apart (the aero of the cars this year allowing drivers to run much more closely to each other - interestingly, in amongst KERS/DRS and tyres, this point seems to have been lost slightly). Crucially, the DRS activation point is set up for cars being within a second of the one in front.

So say driver A is at the front of a pack, with drivers, B, C and D all being within that one second window, but driver E is 1.1 seconds behind D. Assuming A has the quickest raw pace (a reasonable assumption), drivers B, C and D (who now have DRS activated) gain in lap time due to deploying DRS and concertina behind A (while the principal effect of DRS, to aid overtaking, is negated). Meanwhile, driver E cannot use DRS and so loses the propensity to gain that extra half second or so, and so falls back. It essentially allows the (slower-in-raw-pace-terms) cars B-D to run at car A's quicker race pace, while E misses the cut.

It's analogous to the race patterns in road cycling, particularly of the so-called echelons that form in crosswinds. Being in echelon formation (a line of riders across the road, sheltering from the effective wind direction) allows the riders to utilise the lower wind resistance to maintain their position. But fall from the pack momentarily and suddenly being exposed to the extra resistance and get dropped quickly and never regain that position therein unless the pace eases in front.

This was apparent in China, as after about 10 laps there were about four distinct 'groups' on the road, all running nose-to-tail within those groups, but the groups themselves spaced a good few seconds apart. We had:

But-Ham-Vet (covered by 2 sec)
...3 sec gap to...
Ros-Mas-Alo (< 1.8s)
...7s...
DiR-Sut-Kob-MSc (2.2s)
...3s...
Pet
...4s...
Alg-Bue-Hei-Per-Web-Bar (2.6s)
...and the backmarkers

Of course, the tyre strategy had a greater bearing on the final result, in reality, but is an interesting side point none-the-less.

Strategy begins on Saturday

Well, in truth it has done (in various guises) for a number of years - fuel levels, tyre choices and the like have often had to be set before qualifying. But here, qualifying strategy is becoming so integrated with the race strategy, especially with the three-part system affording drivers the opportunity to save fresh sets of tyres for the race. Mark Webber's stunning drive showed the importance of doing so (as, to some extent, did Lewis Hamilton's race). 

This gives rise to some interesting quandries. For instance, is there any real advantage to starting 10th over 11th? If a driver makes the top-10 shootout, might he elect not to even set a time in Q3 and save a set of tyres - particularly if he does not expect to get much higher than 7th or 8th? On tracks with high tyre wear it might be an advantage to use a set of primes for Q1, a set of options for Q2 and save four sets of fresh tyres for the race. In fact, in Canada, one might envisage doing Q1 and Q2 (and potentially, but unlikely, Q3) on the same set of tyres (qualifying...wherever) and have five sets of tyres fresh for the GP itself. After all, if tracks like Melbourne and China are producing three-stop optimum races, then Canada must surely see four stops (at least!). 

Also, is the fabled 'undercut' (where you pit a lap earlier than your rival on track - often at the end of the first stint - thus gaining a 2-3 second advantage with that out lap on fresh tyres) even worth it this year? Surely at some point you have to pay that lap back, perhaps by making your final stop a lap earlier, at which point the situation might turn on its head at the end of the race if your tyres fall off the performance cliff on the last lap when your rival's don't.

Scrapping tooth and nail for grid slots and burning up new rubber seems to be less worth it in 2011-spec F1 when overtaking is demonstrably possible. Furthermore, the differential in lap times available to fresh-tyre runners (Webber, for instance, was lapping at up to 3 seconds a lap faster than his teammate in the final stint) appears to be overcoming the advantage of being a few slots up the grid and the gaining few seconds of field-spread in the earlier stages of the race.

We shall, of course, see in due course.