I am running 27mm and no rubbing issues, with 3.5 negative camber on adjustable front A arms. However, it really depends on the coilovers you may be running. With the TeinFlex I needed to use a 3mm spacer to avoid rub on the inside against the suspension unit. With the Stance, there is no need for the spacer.

On the rear everything was clean.

 

I'm running +30mm (the standard Nismo LMGT4 9.5" wheel). No fitment issues with 275/35/18, 1.5 -deg. camber and koni/rsr combo.

 

heres a question, i had toyo proxes tpt's (soft sidewall) on the stock 17's stock size 225/235 and have the sway bars set to the stiffest in the front and medium in the back and all was well. I just purchased and installed toyo proxes tr1's stiff wall for the rear 255/45/17 and still have the 225/50/17 tpt's on the front(same sway bar setting) the traction control is perfect still and the new rear tires hook up like i couldn't believe, but at high speed the car has a lot of oversteer and just feels very unstable, espesially lane changes! is that because of the wider tires in the rear, or because of having soft sidewalls in the front and hard sidewalls in the rear? or both lol? and if i got 245/45/17 tr1's in the front would it be then back to normal? i'm really in a pickle lol

 

I got the same 225 in front and 255 in back. I just got it recently and feel the EXACT same way as you on the highway. I'm also wondering if 245 will fix it. Bump!

 

bump? and ultrayellow350z do u have the same tires or something else?

 

Different tires on front and back

 

Dave are you sure that our cars are oversteering rather than understreering? I thought small tires on front and big tires on back was understeer more? same all around is more toward neutral right?

 

I'm going through a tire growing pain right now and am currently running different front tires (265 Michellin PS2's) and different rear tires (295 Pirelli Corsas)

I was wanting better traction for my power levels and wasn't really happy with the PS2's. My fronts still had lots of life left so I figured I'd just suck it up for 8 months or so with sketchy handling and that's exactly what it's given me so far.

I have that same feeling of unstableness since the PS2's are very squishy and the Corsa's are very stiff.

It's cold out (50-60 degrees usually) so I figure that's part of it, but yesterday on the highway taking a sweeping turn felt slightly spooky.

Then later when I was making a normal right turn on a normal road I gave it a little more gas than normal and spun into about a 30-40 degree drift or so. I'm lucky there was no other traffic around and it was an easy save. But I still wasn't expecting that to happen normally unless I were to purposely provoke it.

Next tires will likely be some V710's and I'll just continue to keep an eye on the weather forecast for dry weather

 

??????? You are going to buy V710's as your daily driver? I hope not.

 

why not?
I have a celica for a daily driver car and my wife's jeep is usually available as well

They're DOT approved and from what I've been reading everywhere, the V710's aren't super horrible in the wet as long as it's not thick standing water.
I don't drive my Z if it's going to rain and it hardly rains in AZ anyway

But other than the fast wear, I don't see how they're any worse than drag radials on the street, only they'll be nice at handling as well, and it's not like drag radials have much tread when they're half worn out, nor do they last long.

I actually would bet the V710's last 500-1000 miles longer than drag radials would. I've been reading about people's experiences with them on all sorts of places and it seems that even with 6-8 track events, people still get 2000-3000 street driven miles out of them. I know treadwear ratings are incompatible between different brands, but Kumho rates the V710's as having a treadwear of 30 while BFG drag radials are rated to be 0

It'd be neat to not have to change tires/wheels for going to the drag strip, autox, or road courses. Though for drifting, they're probably too sticky for my own good - I'm still planning on getting some 17's and cheap $100 tires for that sorta thing though

The V710's are cheaper than most other 305-315 tires I've been looking at and even cheaper than BFG drag radials
I want to be able to use 1st and 2nd gears again

 

UltraYellow350z i'm not sure, but all i know is my car what ever the cause is definetly oversteering because if i turn the steering wheel even a 1/2" on the highway at normal speeds 60-80 the car will jump or start heading to the next lane and the faster i go the more senstive it will be. but i just ordered some 245/45/17's toyo tr1's for the front and they'll be installed on friday so i'll definetly let u guys know how i make out. what sucks is my other tires are basically brand new but i'm gonna keep them just in case. so i hope this $440 investment works otherwise i'm f@$%ed!

 

thats true, mines is more sensitive, especially when changing lanes. please definitely let me know if that fixes it for you. if it does, i'll have to cash out for new tires also

 

I run Pirelli Corsa 265/35/18 in square fitment. I believe I have ABS/EBD issues by going same size all around. When I take my staggered street tires [255(f) 275(r)] on the track, I get much less ABS/EBD intrusion. However, I have not ruled out braking balance as being the problem (and possible solution). The square setup reduces relative tire grip to the rear, and if my rear is more susceptible to locking up, then there is a higher tendency for ABS/EBD to intrude. If you go with a square set up, I would suggest going with lower pad friction in the rear to offset the shift in relative tire grip. I'm going to buy lower friction compound for the rear because the Raybestos ST41(f)/ST43(r), although excellent race pads, cause more ABS/EBD problems than my previous Cobalt Spec VR/GT Sport combo. Spec VR: mu=.64, GT Sport: mu=.48. I 'enjoy' the slightly oversteering balance and practicality of a square setup, but I can't deny that I feel more comfortable going fast with mildly understeering car. I am certainly more busy at the wheel now.

As for using Corsas for street driving, I would not. These tires are slippery when not warmed up, after all, they are a DOT approved race compound. It isn't surprising that your PS2's grip better in colder weather than your Corsas, even though they are wider. When my corsas are cold (even 65F, mind you), I slip and slide all over the place. Once you get those corsas warmed up, they will grip better than the PS2's.

 

I believe that you have to decide how you want to eliminate your understeer. When you are using sway bars, you are literally redistributing the vehicle's mass. Before you get into all that, why not just add more grip AND eliminate some of that pesky understeer with a set of tires that are the same size all around? Tires can also effect a car's weight distribution, but that gets into sidewall strength and flex, ect. Just as direct an answer to the OP's question as I could: get the tires first, and then relearn how to drive your car. Then work on a sway.

#1 same size tires.
Then remember this typically happens with all cars:

Raise the tire pressure in the rear tires: More oversteer (typically snap oversteer, especially in higher pressures)
Lower rear tire pressure: more understeer.
Raise the front tire pressure: More understeer. That you can feel.
Lower front pressure: more oversteer.
Raise the rear spring rate: more oversteer
Raise the front spring rate: more understeer
Raise the rear shock rebound rate: more oversteer
Raise the front shock rebound rate: more understeer
Add a rear sway bar: more oversteer
and so on

 

Sentry65 - V710's are great tires and are DOT approved. Yet, they are OK in wet conditions as long as there is no standing water. As soon as there is any standing water - watch out.
If you are driving them to and from the track - great. But, if you are driving them to and from work - there is no reason to get them.
I have more torque than you do and I am able to use 1st and 2nd gear just fine. Although - I have to admit that I now used shaved RA-1's and only drive road tracks now. Although I do change to street tires when there is standing water since shaved RA-1's just hydroplane and RA-1's are better than V710's in water.

 

I just realized I am the OP
Thanks for the answer (and all the other people who replied).

So, now the big question for me is, should I fit 265/35/18 width tires on my 18x8.5" rims, or is that pushing it as far as sidewall stability, etc? I would put 255 but they don't make the KD tires I want in that width.

 

Not sure what you are talking about when changing the sway bars - you don't change the vehicle's mass, rather you change the rate at which weight is transfered.
And your comment about changing pressures I would disagree with. Each tire once hot has an ideal hot pressure. Going outside the "ideal" range, if it is higher pressure or lower and you will loose grip.
Yet, your statement is partially true - you can tune out understeer/oversteer with tire pressue to a point.
The proper way to tune a car (if you have enough money) is to get the maximum grip out of each tire as possible. Thus, set all the tire pressures at ideal. Than determine what conditions the driver is seeing understeer or oversteer.
For instance: for Entry Understeer problems solve this by:

a. Soften front springs
b. soften front compression
c. lower front ride height

For mid-corner understeer problem solve this by:

a. stiffen front springs
b. stiffen front anit-roll bar
c. increase front preload

For corner exit understeer problems solve this by

a. stiffen rear springs
b. stiffen rear shock compression
c. raise rear ride height
d. stiffen rear anti-roll bar
(above are cliffnotes taking from GR Magazine published May 2006. Kolia posted the full article on line at that time)

As you can see from above that springs are your most powerful tool when tuning the suspension of the car.

Your overall goal is to have your average tire temperature of every tire about the same. With all tires having a nice linear slope temperature from highest on the inside to lowest on the outside with a 10 degree F change from outside to inside (5 degrees if you want longer tire life).

 

Heck - I fit 275's on 8.5" wheels. I really don't think it will be a problem. Yet, talk to the tire experts at tirerack about this and Luke there has a Z and knows more than I do!

 

MoodDude, what power levels are you putting down?

I'm running the 3.9 final drive, so that probably increases the torque the wheels are seeing by 10%

I dunno, I might get nitto 555RII's or NT-01's instead. I have about 6000 miles left in my current tires to decide

 

Oh he has more than a punny +10% torque...