Well, again a McLaren thread, but I try to keep it a little clear...
I found the following on a website:
They have to run the rear suspension very stiff, as they have very weird rear suspension geometry, an issue that’s hard to resolve, because in regard to geometry, they are very limited. Due to their lightweight aluminium gearbox the team cannot use the pickup points they need, as it would cause structural problems. But despite this, they have been testing a new rear suspension and in reality, it can only be better.
Given the fact that the car is nervous, the unpredictable nature of the Carbon Industries discs adds to the problems. The more forgiving Hitco-discs cannot be used, due to the fact that they overheat this particular car.
Another issue is the Mercedes engine, as it is also on the limit. While it has more power than last years and weighs about 90 kg, it is too fragile in too many ways. They have trouble with the casting, it fails to get sufficient cooling and they cannot get enough heat out of the still quite tightly packed back of the car. The heat under the rear bodywork is also one of the reasons why their carbon-gearbox is not ready to race. They tested it recently in Paul Ricard over 330 km on two days, but over 120 degrees, it started delaminating.
Those are very serious matters... I still stand firm that the MP4/19 is an excellent engineering piece, but apparently they went so far that they forgot about other things. For example the suspension thing... can hardly believe you don't simulate the geometry planned to see if it works before the actual design. Ah well.. chop chop! @ Work McLaren guys