FiveOhNine

I would like everyone's opinions (especially those with experience) about the best way to fix my IS's handling:

Problem: Currently, and most noticeable at highway speeds, my car floats between the lane lines, tramlines excessively due to road irregularities, and in general is just very difficult to control, sometimes even on fresh (read perfect) pavement.

Background: I own an IS350 NON-sport with Bridgestone ER33 tires on stock 18s.

Anti-flame material: I have felt tramlining on previous cars with extreme performance low profile with far more sporty suspensions than the IS. I do not consider 40 series tires 'low profile', nor the ER33 even remotely sporty. On bad days, my IS tramlining/floating can turn my steering wheel up to 1/10 of a turn and nearly put me over the lane line.

I have brought it in to the service department but am expecting to hear that they feel it is normal. I also believe the overly light power steering compounds the problems.

Now, assuming you were spending my money, how would you fix it, starting with the most effective and moving to the least effective mods?

*Note: I would like to keep the ride quality close to stock (or adjustable, via TEAS, et. al.) and avoid making the handling any worse.

I was thinking new tires (PS2s or GSD3s perhaps), wider front and rear wheels (and tires) and possibly an adjustable coilover system.

Any and all comments are welcome!

rfx45

Not to be a mini-mod but I think all your questiosn can and will be answered in the "Brakes and Suspension" sub-forum on the top.

ReLexin

Coil overs most effective.

PhilipMSPT

iTrader: (5)

Tires are definitely your best bet.

Lowering the car helps. Eibachs are best with better handling while maintaining cruising comfort.

There are no body kits out yet that increase downward drag. The IS just isn't made for it.

llamaboiz

2nd

350ripper

just got 4 new Michelin PS2's so far they seem much better handling and much more quiet than my old dunlap sport maxx

projectdna

iTrader: (56)

^ +1

start with springs to improve handling. if you're not looking for an uber-low ride height, eibach pro-kits, tein s-techs, and tanabe nf210s come to mind.

i haven't had tramlining issues w/ my dunlop sport-maxx's (durability comes to mind, however), so maybe a new set of tires might help too...

javyLSU

iTrader: (21)

RUN (don't walk) to your nearest tire retailer and get rid of those Bridgestone Turanzas. I'm still beside myself that Lexus put these tires on some IS's. This will be by far the biggest thing you do to improve the issues you mentioned above. Springs won't really do much to address the complaints you expressed - they're more of a cosmetic modification than anything else.

Javier

kickin8

iTrader: (1)

DEFINITELY the tires!

ER33

SUCKS!

fwynn

iTrader: (1)

Rims+tires are the best!

wider rims+wider tires :]

i ran stock sc with 18x9.5 wheels all around
235/40/18 all around..
unfair race up hill but it was a very fair when we were going down hill

it was 350z, s2k, civic, prelude, sc (me)
350 and s2k won.. no doubt..

civic n prelude were both modded.. really well

Civic (coil overs, roll cage, the works)
prelude (coil overs, strut, rear strut.. etc)

both were killed by the sc up hill n down :] soo yea rims and tires play a SUPER big roll!!

sirkfc

I had heard that the PS2 tires actually make the tramlining worse? My brother had them for a while on his 3 series before and thought something was wrong with the alignment until he figured out it was the new tires.

But I don't know really what I'm talking about...

FiveOhNine

Thanks for all the comments!

Mods, feel free to move this. The reason I posted here was because it is not just a suspension question.

Anyway, my concern with wider tires is that they may exacerbate any tramlining problems, if that is, indeed, the root cause.

I will be the first to ding Lexus for putting such a rubbish tire (ER33) on the IS, so that will likely be the first stage of my attempt to correct the issue.

I should have been more clear with my problem:

The handling (i.e. the cars ability to take a turn accurately in response to user input), while not the best I've ever experienced, is acceptable. What is not acceptable is how the car seems unable, even on flat and smooth road surfaces, to track in a straight line. The constant corrections and over-corrections that I have to make is starting to bother me.

So, with that in mind, any other suggestions?

Should I try tires first, or should i just upgrade to wider rims and tires?

PhilipMSPT

iTrader: (5)

Try tires first. It's the more economical choice. Who knows if the problems will be fixed by then? If it's fixed, then all is done.

If not, then you try the wider rims and tires...

sirkfc

I drive basically in a straight line in relatively smooth traffic for 25 miles each day. I don't seen to notice the drifting issues you do though. you might want to check if your tires are inflated evenly across side to side.

FiveOhNine

Yeah, I've played with the pressures extensively....from 32 up to 41 psi, varying front and rear....still the same issues.