Give it up. There is NO way a stock G37, even with bolt ons is gonna spin the tires under MODERATE acceleration on dry pavement, in FOURTH gear. Bald tires won't matter here.
Do you understand the meaning of "moderate"?
If there were any possibility of you being right, he'd also be spinning them in 3rd, but he's NOT...

 

I have a 7AT and ever sicne I put on the winter tires in blinks the slip light once in a while (on perfectly dry pavement) at highway speeds when under hard throtle. I know its not spinnign anything at that speed (not enough power) but its still makes me a little nervous....

 

mm... did you use the right tire size? I wonder if that's the problem?

 

The tires are 18s so they are a bit smaller (and a bit narrowe) than the summer 19s the car came with. i would not call it a problem, the tires are just of a less sticky compound so they may have some miniscule slip under hard throttle thats enough to trip the slip light, that's all. I guess if my auto car can do it, the OP's manual car when shifted hard on the highway can trip the slip light too for a brief instant. I would not worry about it.

How you drive may affect how hard you accelerte in 3rd gear vs 4th, but common.... There is no such thing as MODERATE accel with our cars... LOL

 

maybe you have a turbo? :P

 

^^ lol, yeah, his good neighbor installed it overnight

Went to the dealership and they blame everything on winter tires, the car is perfectly fine and they can not explain it...go figure, did anybody else try the dealer?

 

If I remember reading the gear ratios correctly, 5th is actually the 1:1 gear