Originally Posted by 4sevens.com
Awesome! And the closer to the edge the smallest amount of power change requires exponentially quicker reflexes to fix the problem or it's spin time. Especially if you're on slicks
I guess it all depends on how a specific car is setup and balanced.
As you reduce the propulsive force due to the higher gear, some of the rear leteral grip is lost due to the shift in weight towards the front. However, since less of the rear tire grip is used for longitudinal acceleration, more lateral grip becomes available (think friction circle).
For a given setup when upshifting, I guess it could be possible that the lost grip at the rear due to the weight transfer outweighs the gained grip from the friction circle. In this instance it could probably lead to a spin...
However, it is not the case in my car. I do feel the change in yaw, but no instability.