I decided to drop my 06 Cooper S with Swift Spec R Springs and while at it, ditched the run flat tires,size 195/55/16 and replaced them with regular Dunlop Direzzas in 215/50/16. Same stock wheels.
I figured with a 1 inch drop, and increase in tire width, not only will the car look great but handle even better then before.
So I picked up the car this afternoon, and while it looks awesome, the drive home was disappointing. The go cart, on rails feel is gone. The car seems to have a weird body roll and the turns are no longer tight, and confidence inspiring.
Could it be that because I was used to the run flat stiff sidewall performance, these new tires are the culprit? Could it be the springs?
It doesn't make sense, I did not gain much sidewall on these new tires at all, could it be that the run flats make that much of a difference?
Any ideas?

 

Make sure the tires are at 38 psi. When they put my tires on it was all over the place and not close..28, 30, 32,29

 

I agree with HRM, tire pressures are probably part of the problem.

I also have read numerous times that new tires require a break in period to perform at their best. Often new tires arrive with a coating that assists their removal from the mold during production. This coating needs to be worn away before tires can give top performance.

 

Yeah the first 50-100 miles of a tire are not very good. Check your tire pressures too.

- drew

 

Thanks for the reply guys. I checked the tire pressures today, all good around 38-40 psi.
I will wait a week or so and see if they "break in".
My hunch is that the tires are just not the right tires for me, given the fact that I like a performance feel, and stiff sidewall. Bummer. Still hoping they improve as I put miles on them but most likely I will pull them next week and look for another set with less sidewall and more performance. Funny thing, my wife asked me last night, "so how is the mini?" drives better then before?
Ohh yeah honey, its awesome! Love it! After spending all this money it's best to keep this to myself and figure out on my own. Don't want her to lose confidence in my superb ability to "upgrade" our family fleet of autos.

 

Well you are going to lose a little bit of that go-kart feel because of the loss of those stiff sidewalls on the runflats. It will take you a couple weeks to get used to them, but in the end, I think you'll find that the new tires probably actually hold the road better while giving you a better ride as well. Oh, and I agree about the coating on the tires needing to burn off. until then, it may feel quite wobbly.

I doubt the springs are a contributing factor because they are MUCH stiffer than stock.