The same way that this year’s McLaren is slower than last year’s iteration. A lack of understanding, and inconsistencies in downforce. According to some sources, this was due to them not understanding the tyre dynamics, which can have an effect on the rear ride height, and therefore the diffuser’s effectiveness. I believe the term is ‘tyre squirt’. Apparently, McLaren, Williams and Sauber have been been struggling with this, though I’m sure it is not the only reason for their problems.
Please don’t tell me that the tyres are also creating fundamental problems in the cars’ performance beside the fact that they are wearing away too quickly on some cars and less on other cars. Now they have to design the entire car around the tyres? Thank god the FIA has seen reason and is keeping the tyres as they are…
Reading between the lines a bit, it sounds like the problem is that the teams have put so much time and effort (and money) into channelling the exhaust gasses over the diffuser to generate downforce that they’ve overlooked the way the tyres naturally deform when load is applied to them. This is something that happens to any tyre – as the air pressure increases, the tyres expand. Likewise, as more downforce is applied, the tyres react to it by expanding.
So I’m guessing that the problem is that the teams have arranged their exhaust flows to get as much downforce as possible, but as the tyre naturally expands and contracts under load, it’s interrupting the way those exhaust gases reach the diffuser, either preventing them from passing over the diffuser, or forcing them to hit the diffuser at a less-than-optimal angle, which is interfering with the level of downforce.
That’s not a tyre problem. That’s a team problem. They’ve become so concerned with the relentless pursuit of downforce that they’ve committed a massive oversight and forgotten abotu the tyres.
I agree, it’s the team’s fault for not taking tyre dynamics into the equation. Obviously it’s not something, which is inherently easy to do though, and I think the reason it is so hard to figure out is because you go to a track, and the way the tyre behaves will be different to the previous track, not to mention the compounds could be harder or softer than before. If any of these teams are able to suddenly find the answer to that problem, then I’ll be very impressed, but I don’t expect it to be any time soon.