I just replaced my standard sport 18 inch wheels/tires from my 545i with Velocity CSL 19 inch and General 245/275 tires. The front wheels were 7 pounds lighter each and the rear were 5.5 pounds lighter each. Compared to the heavier brand tire I had on, each tire I got is 5 pounds lighter. Weighed them all personally. So basically this is approximately 45 pounds lighter mass to spin.

I noticed a signifigant improvement in ride quality, acceleration and gas mileage. I have to say this is the best bang for the buck modification. Not to mention it looks amazing. I went with hyperblack Velocity CSL's. Will put up pictures. I am new here by the way!

 

Ride quality improvement is most likely due to the non-runflats.

I had the same rims. Welcome to the forum....would love the see your pics of the Hyperblack ones.

 

absolutely! any time you reduce unsprung weight you're going to see the results you're seeing. Granted, ditching the runflats helped, but even still, less unsprung weight always equals a better ride, better handling, and better acceleration from a standstill. This is why I always check tire weights before I buy new ones.

 

Steve Dinan told me there are 2 ways to make your car feel smoother. Reduce your unsprung rotating mass, or make your car as heavy as an old cadillac. Just think of it as getting a medicine ball thrown at you while your walking. The heavier the ball is, the more its going to through you off.