Spike100

It's probably all about tires. I suspect that the Wikipedia statistics-graph listing understeer values is based upon running cars with new OEM tires.

My experience
I ran OEM Bridgestone Potenza RE040 (225/45-18 front and 245/45-18 rear) on my 2003 Performance model. When the car and it's tires were new, I noticed a slight amount of understeer (probably due to the staggered setup/size). As the front started to wear (quickly due to the feathering problem), understeer went from hardly noticeable to an ugly handling characteristic. I took the car to the dealer who replaced my feathered 225/45-18 front tires with new ones (OEM Bridgestone Potenza RE040 225/45-18). Nice... new front tires... but handling was awful since my OEM Bridgestone Potenza RE040 (245/45-18 rears) now had significant wear and needed replacement. With new fronts and worn rears, I was actually experiencing oversteer, even with a staggered setup. I also noticed that stiff sidewall plus worn tire-tread potentially equals disaster.

So... I mounted Goodyear Eagle F1 GS-D3 245/40-18 on the front and 245/45-18 on the rear ("square setup"). What a great setup! ...neutral handling, sticks like glue on dry roads, grips very well in the rain, and the ride is comfortable. I'm sure that Michelin PS2's would provide the same great result. Soft-flex sidewalls make the difference. I'm very critical of stiff sidewalls and the fact that drivers using these tires consistently report crashes.

--Spike

Ebony350

iTrader: (1)

^ A very valid point.

Get_Zwole

iTrader: (34)

i agree with spike 100%cant wait to get some money so i can replace my rears with my matching 245/40/18 re01-r's they are sweet *** tires for sure.

moflow

BWahahahh!!!


Thanks for keeping it real Davidv

roast

iTrader: (2)

+1 The re040s grip very well in the summer.

DavesZ#3

iTrader: (26)

Correct. Unless they listed tires or other aftermarket setup info, the chart would be totally meaningless. Normally, when testing or reviewing, you use the OEM config, otherwise, you would try to use the same parts (i.e. tires) on all cars to minimize outside influences.

mattshaver

Since the number is the degrees of steering required to produce lateral G's (from what i can tell), wouldn't steering ratio have a large part to do with this? If the Z has much a quicker steering ratio than any of the other car's then the whole point of the comparison is moot. Right...?

Z1 Performance

iTrader: (564)

how on earth can they quantify this without knowing the alignment settings, or tire pressure, or temperature of the pavement? Also, the test method used is a great way to determine overal lateral G (constant diameter turn that you simply go round and round in, while increasing speed), but a very poor way to determine under or oversteer

you realize any WIKI is only as good as the person typing the info.

simonfencer

I feel exactly the same way about Wiki...just like reading a paper encyclopedia...it is a great jumping off point, definitely not somewhere to stop your research.

As to the understeer issue...very few road cars don't understeer in stock configuration. Of the two, under is way easier for a novice driver (99.999% of all drivers) to handle than oversteer is. Plus weight distribution is only one factor in whether a car has the tendency to over or understeer. Distribution of traction is just as or even more important.

If you put bicycle tires on the front (ever seen the wheels they put on Champcars to roll them around the paddock?) the weight distribution would still be about the same, but the traction distribution would shift way to the rear, and understeer would be about all it would do.

DavesZ#3

iTrader: (26)

I posted this info on my Autocross forum and the general belief is that this is totally bogus. Some of the rankings just don't make sense. Since we can't find the actual article from the magazine that described the test, it's hard for anybody to tell what's really being measured and under what conditions.

Cux350z

iTrader: (162)

mine understeers like no other at the Autox, prolly trying to take the turns ways too fast! driver mod ftw

gjoey66

you should have your alignment checked out...I've heard that lots of Z's were delivered with too much toe in...after the tires wear, they push like crazy...they also hydroplane which caused my first Z to be totaled. if you autox you'll want a neutral toe maybe even some slight toe out...just be careful going high speeds, she'll wander on you.

Justin@IOS

iTrader: (3)

One of the first things I did was grab a set of 245's and throw them on the stock wheels up front. Quick fix until my aftermarket wheels arrive and I can run 275's or even 285's on all four corners. Just that little change made the car handle a LOT better. It's much more neutral now at the limit. It'll come out and bite you if you drive like an idiot (especially in a base model with no vdc), but it's definitely a lot better overall imho.

Spike100

Justin... I'm beginning to think that an optimum wheel/tire setup on the Z is this:

Nismo wheels (or any high quality wheel) 18/8.5" front and 18/9.5" rear, with tires measuring 245/40-18" front and 275/40-18" rear. That setup makes the Z handle really well. To get the best and most safe handling, you choose tires with moderately flexible sidewalls (good choices are Michelin PS2's or Goodyear Eagle F1 GS-D3's).

You could translate the 18" wheels and tires sizes to 19" wheels with appropriately sized tires. With 19" wheels you have better esthetics, but I doubt you get any advantages in handling.

--Spike

DavesZ#3

iTrader: (26)

Actually, your "optimum" setup ought to understeer worse than the OEM setup. The OEM setup had only a 20mm diff in tire widths between front and rear. Your setup has a 30mm diff in tire width which would make understeer even worse. Remember, the reason behind the different tire widths in the first place is to induce understeer by design from the factory.

Z-T

Just my $0.02, but I don't believe the amount of under/oversteer a car has is directly proportional to how well/poor it does on the track. I've tracked some front wheeldrive cars with lethal understeer (GTI, Integra to name a couple) and have blown away every single other car in my class.
My experience with Z so far is that it's actualy fairly prone to understeer with the stock tires and a hot track...just saying, not sure I buy that data in Wiki.
Again, just my $0.02.

Spike100

I understand what you are saying, but my personal experience is that 245's on the front hold very well and are not easily pushed offline (i.e., it's not easy to make a Z with 245's or greater on the front understeer). I don't think this a linear progression, but I am only guessing. Something to consider is tread and the fact that the rears wear faster. It really isn't the width of the tire, but more the width plus existing thread. The handling you have today isn't necessarily what you have tomorrow as tire tread wears and changes the handling characteristics of the car.

--Spike

Justin@IOS

iTrader: (3)

You may have been faster than the other cars in those sessions. But, if the car you drove was more neutral, do you think it would have been easier to drive and/or faster around the track? With many of the fwd cars I've owned, being able to rotate the car made a pretty significant difference in lap times.

Z-T

I also track RWD cars and don't get me wrong, outside of an auto-X arena, I'd say the RWD cars are simply better track cars. They're usually more powerful than the FWD ones, so that plays role...
I was just saying that it's not always a 1:1 relationship between under/oversteer and handling. The right car, track, setup, etc (and driver ) can make a big difference (the GTI does well on autoX tracks but lousy on an open track, etc.).
The Z is actually very well balanced-just as good, even better, as an E46 M3 in my opinion.

Firehawk

Useless misinformation. I have driven many of the cars on the list on road courses and how much the cars actually understeered has nothing to do with those numbers.