When under full throttle my car shifts at about 5800 rpm. When the roads are wet and I am full throttle with the wheels spinning it shifts at 6500 rpm.

Why is that?

 

Traction..

 

So you are saying traction is what determines shift points?

 

Anyone else?

 

same thing happens to me in the rain. i get scared that it might go over redline. i guess i can say thank you to the craptenzas. but anyway, id like an answer to this also.

 

well, if there's no traction, the car can rev more feely. It probably has an internal shift point set up at 5800 and when you have no traction, you approach 5800 quicker than it expects and thus yeilding a delayed shift. That's my take.