Right now my Z is on stock height and it's sitting on 18x9.5 all around (offset is 20 on all 4).

My tire setup is 275/40/18 in the rear with a 1-1/4 to 1-1/2 inch gap between fender and tire. In the front I have 255/40/18 with about an inch from fender to tire.

Only looking at purchasing springs and for that reason I would prefer the springs to be close to the stock spring rate.

Rubbing is what I want to avoid so I would prefer a drop that is less than an inch all around.

I really would appreciate any help on this

 

Tein S Tech sounds like a good option for you. Just make sure to get a quality brand. Their is a lot of stuff out there for looks only with no focus on actually improving the Z's handling.

 

Sorry, I forgot to mention the most important thing. I won't be drifting or taking my car to the track. Just normal driving is all. It is not my daily, so I won't be driving it every single day, if that matters. Thanks.

 

If you're purely interested in the looks, I'd suggest looking at other folks' rides on here and determining what ride height you're looking for. Also, do you want a rake front to back or want the car level? Once you know what you want your ride height to be both in the front and rear, you can then narrow down your search based on that.

If you're looking to change the spring rate and performance characteristics, it's a whole different discussion based on what you're goals are. Since you said you aren't tracking your car, I'm assuming you're mostly looking for a particular "look".

 

You're on stock shocks? I would update those at the same time if those are originals. With that aggressive tire/wheel set up (basically a square set up with staggered tires), you should really update shocks..springs and sways. You're really looking at some serious oversteer there with those front 255/40s on 9.5" compared to 275/40s on same size rims in the rear. You can go conservative with S techs as pointed out. Most *regular* after market springs aren't that aggressive anyway. A great set up would be what I have..Nismo s tune shocks and springs. Less than 1" drop. You can pick em up used like I did. Another route is Tokico D specs..adjustable rates (not a coil over) and you can get em with springs too.

Here's good info:

https://my350z.com/forum/9474093-post10.html

 

I assume you meant understeer not oversteer in above. Also, the amount of inherent understeer/oversteer in the car is a factor of numerous things in addition to tire size. Everything being equal, increasing the stagger between the front and rear tires would theoretically generate more understeer. However, the OP only has a 20mm stagger which is less than stock and is not necessarily bad or good, it is what it is. If he likes it then he should stay with it.

As far as the original question goes. The OPs stance is not what I would consider aggressive. I used to have 18x9.5 +12 and 18x10.5 +15 with 255/40/18 and 275/40/18 with a 1/1.5" drop on Tokico D-spec springs and I rubbed a little both front and rear. Going to -2.5 degrees camber in rear fixed my rear rubbing, but not having a front camber kit up front I lived with the rubbing until the tires were done. The rubbing was minor and only occurred under full suspension travel like on dips.

I since then switched to 18x9.5+15 and 18x10.5+15 with 265/35/18 and 285/35/18 and have zero rubbing with the same suspension setup with some fender gap still present. A big part of your decision will be your choice of tire, as some tires run "big" and some run "small", so simply your choice in tire manufacturer will play a factor. I would preload your suspension by jacking up the opposite corner and then measure your fender gap to really determine how much space you have and then go from there. Once you know how much you want to drop and whether you want linear or progressive then our choice is narrowed down.

 

He has more relative grip up front vs stock. He has a quasi *square set up*..that contributes to OVERSTEER. I know..I have 9.5" all around with 245/40F (225/45 on 8" stock) and 275/40 rear (245/40 on 8.5" stock). Rear end snaps out a lot quicker if I'm not carefull.

 

You can't make that assumption. Sure he has more grip up front due to wider tires and wheels than stock, but he also has wider tires in the rear retaining a 20mm stagger which is the stock stagger. You have a 30mm stagger which would theoretically create more understeer than stock everything being equal, although everything isn't equal so that doesn't even matter.

I think your point is that a 20mm stagger will have more oversteer than a 30mm stagger, which is theoretically true. However you can induce understeer/oversteer with other suspension mods/geometry so all I am trying to say is you can't assume there will be too much oversteer or understeer since we have no idea what he is trying to do, what other mods he has, his driving style, etc. If the OP likes the way his car currently handles then that is fine and he should stay with 255/275 stagger. If he feels the back end comes out too easily then he can consider wider rear tires or other mods to counteract that.

 

His set up: 255/275 on 9.5 wide rims. Difference 20..MORE RELATIVE FRONT GRIP than>>>>
My set up 245/275 on 9.5 wide rims. Difference 30.
But that's not my point..they are really pretty much the same, since my 245s are spread more (stiffer side wall) on the 9.5" rims.

My point...the RELATIVE GRIP on the fronts on BOTH these set ups (basically the same stagger) is MUCH greater than stock. More RELATIVE front grip>>> means more OVERSTEER. Again...stock FRONT 225/45/8.0 REAR 245/40/8.5.
With new set up you have FRONTS at 245 (or 255) on 9.5!! Go figure contact patch with those tires and rims compared to 225 stockers on 8".
Rears also increase with 275s on 9.5 but not as much as the fronts. More RELATIVE contact going to the fronts>>>>more oversteer..given no other changes are made at the same time.

 

This is my last response since I didn't mean for this to be an argument about what creates oversteer and this doesn't help the OP. I was responding to your first post where you say "You're really looking at some serious oversteer there". Is he really looking at serious oversteer? Do you know how much oversteer he wants/needs and what his other mods are? Should you be commenting on how much oversteer he will have? That is my point. Didn't mean to argue. You obviously know what oversteer is. Thank you. Goodnight

 

I guess this is what having a forum is all about...not trying to pick a fight or argue. I respect all opinions and points of view..yours included.
Let me finish this discussion on this note>>>>I would have LOVED to mount my 275s on 10" or 10.5" rims to match the 9.5s up front.

 

Wow, oversteer should not even be discussed with the Z. Right now running 275 front and rear mine is pretty neutral, but i can turn to oversteer with driver error , same as i could do when running a 255 front and 275 rear.

 

So you've picked a tire/wheel/offset choice that will not clear throughout the suspension's entire range of travel

Assuming you didn't do that, Hotchkis will give you what your looking for. Not a excessive drop and they have very specific R&D for your 2003 shocks.

oem 2003 spring rates
314/342


Hotchkis 350Z Linear springs .6”/.8”
Spring rates in lbs 340/330



Here is John Whatley of Hotchkis talking a little bit about the setup on a 2003/2004 Z It is in responce to a email complaint about their rear spring rate being too soft vs oem.

"There is no error on the spring ratings. The rear spring is in fact softer than the stock. The reasoning behind this is that: during testing we found that the rear end likes to bounce under hard cornering. By reducing the spring rate in the rear we were able to get more MPH in slalom testing and stopped the bouncing that occurred. These springs in conjunction with our swaybars will be matched with each other to provide a neutral feel under hard cornering."

 

Agreed

 

What size rims?
What you say is very true..however, with a square set, the *envelope* between neutral and oversteer is considerably narrowed...allowing much LESS room for error and aggressive driving. I now find myself being a lot more *tentative* in mid corner and exit. I do love 9.5s all around though..90% of the time, that is.
I'm going to do 2 things soon. Match the stiffer rear bar (Tanabe non adjustable) with a Cusco (knock off) front bar...and..increase the rear track with 5mm spacers. I'll report back results on a new thread.

 

Interesting.. I have 245/40s front on 9.5s with a 25mm offset..no problems.
I guess that extra 5mm of tire on either side and another 5mm outboard on offset causes suspension rub up front?

 

I can't comment on the limits of offset and tire size clearances. I just figured since he brought up the issue,....it might be a issue. But, I do know that a 255/40-18 tire is taller and wider then a 245/40-18 tire , bringing you closer to the fender. And not all tires are the same demension's one make and model to the next in any given size catagory.

 

Yeah..TALLER..may have some issues there too?
Over my set up (245s), he's adding a net of 10MM to the outside and 5 to inside. That and the fact that stock Diam stagger is changed (VDT issuses?) is the reason I ruled out the 255s up front.

 

Thanks for the help. I think I'll be going with hotchkis. Spring rate is close to stock and I'm guessing I'll have no problems wearing out my shocks any quicker than with stock springs. My only concern is rubbing. The rear tire comes out to line up with the fender. And from the top of tire to fender I have about 1.25-30 inch gap. Springs will drop me .75 inches in the rear. Let's say I have a .3 inch gap after the drop. Do you guys think I will rub? Thanks!

 

You will be fine, i have run a similer setup inn the past. You may have to trim the screw that holds the front fenderliner in place at the most. That is what rubbed on me , but i had a slightly more aggressive front wheel