[synolimit]

Just curious, who’s done a different wheel and tire combo?

If this was a video game and we went by rule of thumb only, what would happen if we went from the oem 19x11 19x12 305/30/19 325/30/19 to a 18x11 18x12 315/30/18???

The tires are now square, we gain 10mm in the front, lose 10mm in the rear, but it’s not a real square setup because mounted on different size wheels will affect the tire a little. We also lower the car over a 1/2” but total diameter is over 1”. And we drop a little weight on rotational weight.

Obviously dropping rotational weight is great all around. Lowering the car probably also great for aero and handling. But what affects will happen with a square tire and having the diameter greatly change?? I’m assuming horse power might pick up, speedo will be way off, and will I get more under steer? Over steer?

[Baddawg53]

Little different than what your sizes are, but I went from 1LE 20 inch super car 3 tires and wheels to a square 315/30/18. Definitely more oversteer, speedo off by 5 mph for me. I've hit the rev limiter a couple times in third thinking I had more room before I needed to shift. Definitely feels quicker with the difference in wheel weight and the smaller circumference changing the gearing. Also I have to turn all the nannies off because the computer doesn't like it.

Sway bar adjustment took care of the oversteer.

[synolimit]

Originally Posted by Baddawg53

Little different than what your sizes are, but I went from 1LE 20 inch super car 3 tires and wheels to a square 315/30/18. Definitely more oversteer, speedo off by 5 mph for me. I've hit the rev limiter a couple times in third thinking I had more room before I needed to shift. Definitely feels quicker with the difference in wheel weight and the smaller circumference changing the gearing. Also I have to turn all the nannies off because the computer doesn't like it.

Sway bar adjustment took care of the oversteer.

Ok cool. Rear sway bar adjusted? Stiffer or softer? I’m still on the middle oem setting. And if you hit the limiter, you gear down right? So top speeds lower but faster closer shifts?

[Baddawg53]

I went softer on the rear bar, from the stiffest setting to the middle setting. I have the Hotchkiss bars front and rear.

I definitely have to shift at lower speeds than I used to. The shifts come faster than they used to, but I think one of the advantages is when I used to shift 4th to 3rd around a corner I'm more comfortable leaving it in 4th coming out of it and having enough power to pull on the next straight. I definitely had to change how I was driving, the first couple laps were tough.

[synolimit]

Originally Posted by Baddawg53

I went softer on the rear bar, from the stiffest setting to the middle setting. I have the Hotchkiss bars front and rear.

I definitely have to shift at lower speeds than I used to. The shifts come faster than they used to, but I think one of the advantages is when I used to shift 4th to 3rd around a corner I'm more comfortable leaving it in 4th coming out of it and having enough power to pull on the next straight. I definitely had to change how I was driving, the first couple laps were tough.

Gotcha. Awesome! I think with square and oversteer a front would be better to get stiffer. I’ll check out hotchkis when the time comes. I never did get my 370z right but I played with square, hotchkis front, oem rear, the g37 rear and no rear. Still never felt right.

[Baddawg53]

I debated front vs rear bar adjustment. I am not anywhere near the limit of the car and wanted to leave room for adjustments in both directions, so as I get better I can have more flexibility in what I can do. Absolutely no science behind my thought process.

[rotis]

I've got a couple square wheel sets.

325/30-19 SC3 on 19x12 square
315/30-18 Nankang CR-1 on 18x12 square (I've also run A052 on these)

I'm running a larger front bar, the rear bar is either in the middle or on soft, depending on balance. I'm also running MCS doubles, which accommodate the extra wheel/tire clearance in front.

[Baddawg53]

Originally Posted by rotis

I've got a couple square wheel sets.

325/30-19 SC3 on 19x12 square
315/30-18 Nankang CR-1 on 18x12 square (I've also run A052 on these)

I'm running a larger front bar, the rear bar is either in the middle or on soft, depending on balance. I'm also running MCS doubles, which accommodate the extra wheel/tire clearance in front.

Do you have a preference for which setup you prefer? 18 or 19?

[synolimit]

well my questions pointless now haha. just picked up a 1 track day set of Apex SM10's with Hoosiers A7's for less than half new! he put 315/335's on them so im still staggered now. it will be interesting to feel the difference of 23 less pounds and going to a slick.

[rotis]

Originally Posted by Baddawg53

Do you have a preference for which setup you prefer? 18 or 19?

Just different tires for different purposes. The SC3s are for big track lapping, the 18" wheels are primarily AutoX since they either have A052s or CR1s mounted.