Originally Posted by BMRu4ia
Could I assume that if my e90 was equiped with non-RF that if would be a smoother ride?
Or is the difference not that noticeable.
It's really hard to say. One person said that they didn't notice any adverse effects from going to 19s with non run-flats. Run flats are heavier by up to 10 pounds per tire (from what I have heard) so it stands to reason that less unsprung weight would make for a better ride.
But being that the suspension in the E90 is apparently tuned with run-flats in mind, it's hard to say what a lighter wheel/tire combo would do. I know that the ride on the E90 with run-flats is much better than it is in the Mini and the 5 series with run-flats.
Conventional wisdom is that less unsprung weight will definitely help the ride.