i bought my car with RSR drift springs on it. it handled like a roller coaster on the old tires (245/40/17) all around. i couldnt find any reason to complain but i needed some new rear tires so i found a crazy deal and bought 2 245/45/17. now the car seems like it wants to oversteer and dance out from underneath itself in turns over 40 MPH especially left turns. does anyone have any experience with these springs or drift springs in general? i heard that drift springs are different because they can be adjusted to the point where the tire sits on its side and slides out very easy. with the taller tire in the back do the springs need to be readjusted? how do i go about adjusting it to where i need it?...

 

You just jacked the rear end of the car up 1" as compared to the front. When you jack up the rear, it makes the rear of the car unstable -- I have personal experience with this when I had an issue with my suspension. I really didn't enjoy sliding sideways off track at 80 mph into dirt.

I advised you against this in your other thread.....a "crazy deal" isn't a "crazy deal" if the tires aren't the right size.

 

how are they the wrong size? if this is the problem then by putting my rear tires up front and buying some 265/45/17's to go out back should solve the problem...

 

I would recommend sticking with the factory wheel/tire diameter by using 40 profile tires on 17's.

I think rynberg is refering to a number of things (e.g. caster) that get out of whack when you lift the rear like that.

 

Raising the rear ride height by using too tall a tire and leaving the front alone raises the rear roll center in relation to the front. Since the front roll center height didn't change and the rear roll center became higher the car will tend more toward oversteer.

If he's having real trouble I seriously doubt it's the roll center's fault, it's the fact that he has two different brands of tire on front and rear. Of course each end of the car will act differently now.