Understeer Anyone?
 

I put off writing this Thread with this question for months thinking it was just my imagination, maybe my tires, or maybe just the way I drive. But I have noticed an understeer in my '09 Z for a while now. I currently have 30k on it. When rounding a corner at speeds of 50+ mph, it seems I have to really concentrate to make the car go exactly where I want. There seems to be a fraction of a second of a delay in turning and it doesn't matter if it's a left or right turn. It seems like it's been more noticeable since I got my Michelin Pilot Super Sports or maybe I just didn't notice it when I bought my Z which had Potenzas. I searched here for threads regarding this issue and didn't find any so maybe it IS just my imagination. Anyone else feel this way? It's really just an annoyance but it seems that I never felt an understeer in my '07 350Z.

No other mods to the suspension other than you got new tires?

need more info....

You need swift springs and sways, car still sketchy.. Reviews say it all

When was the last time you got an alignment?

All stock and had it aligned when I got the Michelins about 5K ago!

Doesn't sound normal to me. Have you looked under the car to see if something's tweaked?

Not yet! I'm going to have Nissan look at it when I bring it in for service soon.

Look for worn out bushings or ball joints. Something's wrong, and it's not the tires.

Thanks Chuck :tup:

Could just be a combination of the softer sidewalls on the PSS and full tread compared to your old, worn down Potenzas. When you wear tires down you eliminate or reduce tread squirm, so they will feel sharper than when new.

That's what it sounds like to me.

Keep in mind the Z is a front-heavy car with staggered tires. Its bias is towards understeer.

If nothing's tweaked in the front end, this is the issue. A set of adjustable sways will solve the issue quite nicely.

A lot of it is just dealing with it and getting used to how the car drives now. The PSS are softer and not quite as sharp feeling as the Potenzas, but they grip oh so much more.

That has been pretty much my theory. The Michelins ARE noticeably softer! Thanks! :tup:

Great points...Thanks! :tup:

No problem. :tiphat:

im not gonna lie i love the PSS, they are even good in the rain for me. Its the same as dry more or less

Yes I swear by PSS. Can't wait to wear my Potenzas out. :)

Yes they are very good in the rain as I drove mine all winter long but I have to admit, the dry handling of the Potenza's was sharper and I'm not sure I would get the PSS again.

They may feel sharper, but the PSS will run laps around them.

My hankook's are also a softer tire but if anything I would have to say I get oversteer a lot more than understeer when pushing the card hard.

interesting, i'm also running hankooks k110 v12. i've gotten more understeer than oversteer in the canyons. i'd say the only time i'd actually end up with oversteer is when i feel like whipping the car around a 90º turn. i've learned my lesson, been there/done that, i don't really do that anymore after i bounced by stock rims on the curb.

whats your setup? i'm currently running 305/25/20R and 255/30/20F. It's more show than performance (theres a reason why I don't have them fancy ultra-lights or te37s), but it still gets the job done.

I know that hankooks are known to have soft sidewalls, so i believe thats whats causing the understeer. yet, i think i managed to remedy that issue (okay, maybe a not at all) by running 25-profile/30-profile rubber bands.

When the tires were really warmed up on the track I would get some understeer but it would usually end up switching to over-steer at the end of the turn.

My rears are 295/25/19R and fronts are 275/30/19F I believe (going by memory).

I ended up getting some damage when I went off the track at chuckwalla valley because I got oversteer in a section I wasn't expecting it (I can usually deal with it if I am expecting it). Initial counter steer timing was fine but I panicked a little and let off the gas which totally screwed me over. Lesson learned there =P With FR letting off the gas when your getting over-steer is a very bad idea =P

EDIT: This *of course* is with VDC turned off. I would think VDC on would pretty much prevent over-steer (in most situations) and all you would ever get is understeer.

Let a couple of pounds of air out of the back tires and see if that changes anything.

The Z has enough power to oversteer on exit.

EndyKwon, your extreme stagger is why you feel the under steer, not soft sidewalls. 255/305 is a huge amount of stagger on a front heavy car.

Staggered tires, a bit more weight in the nose, but oversteering at the apex saved me numerous times in my z

Did you have VDC ON? VDC ON increases understeer a little going into high speed turns. If so? Try the same turn, under safe conditions with VDC OFF. From there assess the differences and mod accordingly.
My mods are Swifts, eibach alignment and sway kit. It helps understeer a lot. But i feel i can use better damping settings to increase control. So either Koni yellow, KWv3 or JIC Magic FLT2 will go on my car next if i can find them.. Had them on my G and they were awesome. Not sure which way to go when i do? That will have to wait till fall though. (house hunting)

Dampers and tires are really the best thing you can do. Sways are nice but are more normally reserved for fine tuning once you've got your damping where you want it. Even just a switch to Konis will be a huge improvement over stock.

Since you already have Swifts and it seems like you DD your Z, I'd just get the Konis. Most bang for your buck at this point.

How so? Please elaborate.

Just how bad is the steering response on the PSS's? I was thinking of going with stock sizes on the G when tires are needed (probably end of this year or next spring). Stock sizes are 225/50/18 front, 245/45/18 rear. Over on the G forum, folks are saying the contact patch of the pss is flatter than that of the re050a's which, while the pss has softer sidewalls, does not necessarily reduce steering response or sharpness.

Steering response is still very good (in my experience). It does seem a little more muted than tires like the RE050A and PZero, but it offers a lot more grip.

I think more often than not a lot of the criticism about the lack of response is more related to going from worn tires to full tread. You could go from a worn RE050A to a new RE050A and feel less responsive steering because you've now got full tread to squirm about.

^^Thanks. By the time I'm ready to buy there will hopefully be more feedback (in stock sizes). The other tire I was thinking of was the potenza s-04.

I have absolutely no reservations about recommending the Super Sports. There isn't another tire I would want on a daily driven street car.

Thread resurrect! I even put on some new bits and I was feeling like the car was pushing a bit, but when I looked at my entry speeds, they were equal too or better than what I was seeing with worn tires and what felt like a more neutral entry.

I think your hypothesis is right on here.

JT

tirerack has shaving services

Could change a lot with the alignment too.

I had my GT-R changed from the track camber setting to a more relaxed setting and it really changed the behavior of the car (a lot more so than the nissan GT-R tech was saying it would). The GT-R in its normal setting mostly gets understeer as well if you take a turn to fast but with the more 'street' instead of 'track' setting which was like -1 degree vs -2 degrees of camber the car would start get oversteer at the limit. I personally prefer getting understeer rather than over-steer as its easier to cope with (IMHO) and you potentially overshoot vs going into a spin.

That being said on my Z it seem to very a lot depending on the situation. I would say my Z was always more likely to get oversteer than understeer but I got a bit of both. Its probably changed based on alignment settings that I never really asked/cared about before I had my GT-R.

i read GT-R and didnt see the rest...

Ya, he did comment on a 2 wheel at the end, but ya 2w 4w is apples and oranges or apples and a platypus. :gtfo2: lol

I didn't know that, not that I can afford to shave off rubber without a fun factor. I will shave them with the throttle. :ughdance:

yah, i think people that compete use that service. i personally would consider it if i had a blow out on one of the rear tires that were like partially worn.

Exactly.

these cars understeer. crappy corner entry, quick corner exit. welcome to the z world