How to screw up your cars handling and ride - step by step!

[andrew20195]

Originally Posted by mit_peid

For some reason I doubt most of the people going 9.5" square are maximizing overall performance (although I do agree it looks pretty good with 18x9.5" if you can make them fit). Problem is I believe generally you need coilovers with a smaller diameter than stock (and some camber adjustment) to make 9.5" fit up front. Everything seems to be a compromise with no real clear right answer on this if you're trying to 1.) maximize handling performance 2.) without impacting throttle response & MPG too much and 3.) look good doing it.

All of this is true, but if you need the wider tires in back due to power, you aren't really limited too much on how large of a square setup you can run.

That being said, 265s are probably overkill for any "reasonable" forced induction power level.

[dradernh]

Originally Posted by Kostamojen

I was at least able to...increase corn[er]ing speeds dramatically even if I did sacrifice the handling characteristics of the car.

Can you explain this further?

[gramicci101]

For the experts: what is your opinion of a square tire size, but lower offset wheels in the back?

For example, 17x8+45 in the front and 17x8+35 in the back, with 225s all around.

[7thgear]

Originally Posted by gramicci101

For the experts: what is your opinion of a square tire size, but lower offset wheels in the back?

For example, 17x8+45 in the front and 17x8+35 in the back, with 225s all around.

higher offset means more strain on the bearings and a requirement to get longer studs as well.


but you're increasing your track width, which reduces weight transfer by a small amount.


just got to think about how all this factors into what you want

[FR-S Matt]

Been running 18X9.5 for a while now with KW V3's. I would say my car handles significantly better than stock, and rides better, and I'm lowered about 1.6". -2 camber in front, -1.3 in the rear. It's a balancing act.

Yes, they clear in the front with plenty of room. My RP03's are lighter than stock even in a larger size. Car looks great, handles great, can't complain.

This is a good thread and its things like this that helped me plan out how I wanted my car to turn out. When you cheap out on coilovers, you realize the mistake you made once you put on a more expensive, more adjustable, more reputable set. That's only part of it. Adjusting it properly is the next part.

I may look at other parts to further improve my ride with bushings.

[7thgear]

Originally Posted by FR-S Matt

I would say my car handles significantly better than stock

so you have before and after lap times? How have your autocross times changed after the upgrade?


when you changed suspension did you also change the tires?

[FR-S Matt]

Originally Posted by 7thgear

so you have before and after lap times? How have your autocross times changed after the upgrade?


when you changed suspension did you also change the tires?

245/35's which match the stock speedometer.

Haven't put my car on the track to see. It's a street car more than anything.

[7thgear]

Originally Posted by FR-S Matt

Haven't put my car on the track to see. It's a street car more than anything.

so how do you know if your cars handling is actually improved?


Having a lower car with a stiffer ride certainly translates your inputs quicker, so you feel like the car is more responsive, but until you start navigating the car at the limit I'd caution about making claims of "significant" handling improvement..

a lot of which can be attributed to a tire change more so than suspension.


the key point is to be very specific with the descriptions. A car with crisp response is more specific than the more generic "handling"

[Racecomp Engineering]

Originally Posted by hattrickey

With a 1" drop using a 17x9 wheel, what would be the difference between a 245/45 and 255/40 tire?

245/45 is pretty tall.

[gramicci101]

Originally Posted by 7thgear

higher offset in means more straight on the bearings and a requirement to get longer studs as well.


but you're increasing your track width, which reduces weight transfer by a small amount.


just got to think about how all this factors into what you want

The weight transfer thing confused me, until I realized you meant side to side, not front to back.

[Racecomp Engineering]

Originally Posted by mit_peid

How much more power before entertaining a staggered setup as an option? For example, if you have a ~250whp FRS/BRZ.... would going 18x8.5 (F) and 18x9.5 (R) be all that much understeer? AP2 S2K had a slight staggered setup and it only had 240bhp stock (but I'm sure I'm comparing apples with oranges at this point).

That's pretty wide, but it can be fine. It's a compromise...and one that I think functionally at least a thinner tire with a stickier compound would have the advantage. Longer sessions or races...staggered might begin to make sense around there but you'd have to do some testing.

- Andy

[Racecomp Engineering]

Originally Posted by welllam

I come across a set of used Work emotions cr at 18 X 8.5 Et 38 and 18 X 9.5 Et 38 as well at a good price. This set is for form over functions as I have a prf 17*8 for tracks.
Reading this thread gave me some doubt because of the disadvantage on staggered set up. If I mount 245/35/18 on front and back will be still a squared setup and doesn't affect much the handling?

Same width tire front and rear is better, though it's a bit of a stretch for the rear. My concern is just that it's extra weight that isn't helping, but if you have a separate set for the track, that's good.

- Andy

[Kostamojen]

Originally Posted by dradernh

Can you explain this further?

Sure.

With the tires/wheels, springs, swaybars I have now the car is indeed capable 15-20% faster speeds in corners. But the progressive handling charecteristics are gone. This is what I would classify as a "grip" setup now, and when that grip does finally give way, its much more sudden and less controlled. Nothing at all like it was before.

The lost off some suspension travel and the rear swaybar have also caused the rear inside tire to lift more in cornering which is not what you want in a RWD car with a LSD. I think a better (very expensive) suspension setup might be able to compensate for this, but at the same time might change the car even more.

[totopo]

Originally Posted by Kostamojen

Sure.

With the tires/wheels, springs, swaybars I have now the car is indeed capable 15-20% faster speeds in corners. But the progressive handling charecteristics are gone. This is what I would classify as a "grip" setup now, and when that grip does finally give way, its much more sudden and less controlled. Nothing at all like it was before.

The lost off some suspension travel and the rear swaybar have also caused the rear inside tire to lift more in cornering which is not what you want in a RWD car with a LSD. I think a better (very expensive) suspension setup might be able to compensate for this, but at the same time might change the car even more.

haha haha, 15-20% faster? So since lateral acceleration needed is squared you are saying you have 32-44% more lateral acceleration? So that would go from a stock 0.89g skidpad to 1.18 to 1.28 g skidpad? Holy crap your car would have to grip better than like corvettes on hoosiers