I don't know how but it happened to mine too.

 

Hmm, strange. Here it is again.

 

I really need to test my OEM 18's vs OEM 19's. When I first got the 19's I noticed they felt lighter than the 18's so I wonder if 18's would still put more power to the ground. I then started using the Pilot Sport PS2's and they are some of the lightest tires I have found. Freaking pricey, but light and great performance.

 

It all depends on the specific moment of inertia. Every make will be different.