samsniss350z

chances re you could do a better rolloing job than some of the 'pro's' If you just take your time

N80

I'm resurrecting this old thread that I started a long time ago.

I've been running 265/35/18 Hankook RS-3s on Enkei RPF-1s (+15 offset) at all four corners for about 3 years now. They do not rub at all. They have held up great but it is about time to replace them.

Having run this size all this time I do not think it is the best size for the tracks I run. I always seem to be running out of RPMs in third and fourth gear but too late for a shift to be useful. Fifth on the back stretch at VIR is fine.

The car also feels much more peppy with the stock oem tire size (on the street).

I know that a 265/40/18 will work front and back because I've run them before on these same rims. No rubbing.

But, a 275/40 would give me a wider footprint AND be as close to the stock diameter as you can get.

I would anticipate a potential rub on the upper suspension arm/spindle on the front since it is already close with the 265s. A 5mm spacer would probably solve that problem but might create or worsen a rub at the fender.

I've read about professional and DIY fender rolling. Not real into that. Don't have the budget adjustable camber arms yet.

But someone mentioned just giving a front fenders a yank by hand. My car looks okay but it is 10 years old, lives outdoors year round, is my daily driver and has been wrecked several times. So I'm not too worried about looks. Anyone done this successfully? If so, do you pull the fender upward or out? Or both?

terrasmak

iTrader: (8)

Just pulled out, both hands , give it some pressure , simple and easy

Richard Toss

Piggybacking on this old post.

Recently installed 275/40 Firestone Firehawks mounted on 18"x9.5 RPF1. It is rubbing over uneven blacktop. I believe a fender roll is in order.

The issue, if anyone will ever read this, is that it seems that only the driver side rubs. This leads me to believe I may have a bad shock.

Comments?

Editing to share that it is a square wheel & tire setup

N80

How much do you weigh?

And thanks for posting. I have the same wheels and was looking at the same size tires so its good to know that that combo does in fact rub. I think I am going to go with 265/40s since I know they will not rub. They won't give me any more footprint than the 265/35s but they seem to work much better with the gearing....at least on the tracks I drive.

Richard Toss

6'-1" 175lb HAHAHA!

Yeah driver side is rubbing, passenger I haven't felt rub yet. Leading me to believe I have an issue with my driver side suspension.

I'm not a suspension guy by any means tho. Maybe I should post this in the suspension thread, but any guidance here will certainly be appreciated.

travlee

iTrader: (8)

what year is the car and mileage? very possible it is a blown out shock

N80

I would think that if it had a suspension issue you would have noticed it before changing tire size. Go somewhere flat and measure side-to-side ride height. It won't be exactly equal but should be close. Shove down on the driver side front and rear and see if you get excessive bounce. It should rise back up and then settle and that's all. Obviously take a look at the shocks and struts and make sure you don't see any obvious leaks or damage.

Richard Toss

2004 Touring, just rolled 63,000mi

Measuring is a good idea, I'll try that this evening. I did push down and noticed no unusual bounciness. I didn't notice any leaks or damage to the shock or strut when I did brakes and tires last week, but I wasn't looking too hard.

A guy I talked to said I may have a bad shock, and that it won't necessarily be noticeable to the naked eye.

I really didn't want to modify the suspension from OEM but it is looking like a perfect excuse to go with a quality aftermarket setup.

Thank you for you comment. Just be aware my issue here. It may be the case that my wheel/tire setup won't rub with a properly functioning suspension.

N80

Personally, if you're not in a position to see improved track performance from a suspension change or if you're not into the looks/stance mods....I'd leave the suspension alone because if you are going down the road of changing ride height, spring rates, larger wheels and tires that gets real complicated real fast and often leads down the path of making mods you didn't think you needed in order to accomodate mods you thought you needed.

Not sure how your problem could be a bad shock. The spring determines your ride height. The shock controls the rate of compression and rebound. But I'm not a suspension guys either.

My car is an 07 Enthusiast pushing 90k miles with lots of track time. Original OEM shocks and struts are just fine.

MicVelo

^^^ This.

N80 is absolutely correct that it's the spring that is the determinant of ride height with the shocks controlling movement of the spring.

That said, a bad shock *could* contribute to the rubbing problem but it's doubtful.

I strongly believe it's just good old tire clearance issues. Out of the 15-some sets of tires/wheels I've run on my 33s, everything cleared with NO issues until I put on my RPF1 - 275/40s in the same size & offset as yours - 18x9.5 +15 square - and immediately had clearance issues over irregular roadways.

Rolled the fenders (about 70-deg from stock), NO more issue. Currently run 285/35-19 (on 10.5 +22 on one set and 10.5 +14 on another) without a single problem.


285s on 10.5 +22


"Mere" 275s on equally "mere" 9.5 +15 (offset is everything!)

Richard Toss

Really appreciate all the input.

When I said shocks I meant springs. Ooops! Could be a bad spring not noticable to the naked eye. Anyway, it sounds like that might not be the issue. Just strange that one side rubs and other does not.

Thanks N80 for talking me out of suspension upgrades. Mods to accompany other mods does not sound fun, and I'd really like to keep practicality intact.

From the sounds of it, Mic has had rubbing issues with a similar setup.

Tough finding a reputable shop around here to do fender work but after this conversation, fender rolling is the direction I am going once I find someone to do it.

terrasmak

iTrader: (8)

Let's throw the logic in, rear alignment specs are from -1.1 to -2.1. The different between the settings is slightly over 10mm of clearance on the outer lip. Most alignment monkeys get the alignment in the green and walk away. In the green means -1.1 to -2.1 , so that means one side could be at -2.1 and the other -1.1. Could be -2.1 and -1.8 , I hope you are flowing here.

So with the above understanding, where do you think a good place to start will be ?

Not a bad spring either. The spring or shock on a proper setup have nothing to do with rubbing. Remove the spring, suspension should sit on the bumpstop, if components are proper, you will not rub.

Btw, a shock only dampens the suspension movement. If you rub, it's always a different problem i.e. Bumpstop, offset,

Richard Toss

Do the alignment specs above represent camber angles? I may have more negative camber on the passenger side than the driver side, and that is why I am rubbing?

Are you suggesting that I should not rub with this setup, and it is the result of bumpstop, or offset?

Thank you for the reply, but I'm not sure what bumpstop and offset are. I understand my wheels have an offset, but I'm not sure that is what you are referring to here.

Unfortunately I'm left with even more questions at this point

N80

terrasmak, it has always been my understanding that the Z has little or no camber adjustment, at least up front. Maybe I'm wrong about that.

But, what I think he is trying to say, Richard, is that the difference between one side rubbing and the other not could be an alignment issue. While this is certainly possible I still don't think alignment will solve your whole issue.

What he is saying about the bump stop is that there are rubber or urethane stops that limit the upward suspension travel when you hit a bump, etc. With proper tire clearance even when the suspension is fully compressed against the bump stop the tires should not rub.

I wouldn't get worked up about any of this. You paid a lot of money for a tire and wheel combo. It rubs sometimes. It will probably rub worse if you hit a big bump. The easiest answer, short of selling your new wheels and tires, is either having someone roll your fenders or 'pulling' them as terrasmak has described above. Certainly no harm in getting a proper alignment but here is a confession: I haven't had an alignment in the 5 years I've owned the car. Tire wear remains predictable on and off track.

And beware of chasing alignment specs for tire clearance too. That can lead to tire wear issues.

N80

Now for my soap box (purely my opinion):

Avoid mods. My first track day instructor ever was spending his weekend instructing me and not driving because some mods he'd made to his car had caused problems. The first thing he told me was don't mess with your car!

The thing is that very, very smart people designed these cars and for the most part they did a really good job. When you mess with that design it affects other things and you can quickly get on the mod treadmill as I mentioned above.

I know mods are popular. I know they make your car stand out. I know that when properly done they can improve performance.

Other than replacing the OEM non-Brembo brakes with OEM Brembo brakes I have made no mods to my car. I have the tire/wheel combo mentioned above for track days. All other times I'm on OEM sped tires and wheels.

A lot of people say that is boring and they may be right. But I drive my car to work every day and drive it on track 5 or six times a year. I have very few problems with it. It is just dead reliable and fast enough for me (I am an instructor and do not race or time trial.)

Yes, there are some simple mods that would provide better track performance and maybe better tire wear. But so far my tire wear is affordable and knocking a tenth off my lap time at VIR isn't going to make my track day that much more fun.

So think about your mods. Think clearly about why you want to do them and then research what goes into it, how effective it would be and how else you could better spend the money.

MicVelo

^^^ This. So much this.

Long [ soapbox ] response since N80 just stepped down and gave me space at the pulpit. Laff...

I DO agree that for most drivers, mods are superfluous and pretty much reserved for the bling factor.

However, there is that percentage of owners who are savvy and talented enough and who can certainly take advantage of modifications to suit THEIR needs. I know many here that modify not for the bling but for the satisfaction of a "tailored" car. I know that I fall into that category. While I admire many of the owners' cars here that have all the bells and whistles, it's just not what I want/need to have fun.

But here's the thing... many people modify their cars (any car, not just Zs) without thinking it all through - and that's where the "mouse wheel" of mods starts to come into play.

Examples:

- An example drawn from this thread: Lowering a car beyond what the stock alignment can handle and finding out it's not just buying and installing a set of coilovers that drop the car 2.5 inches; because then they find out just how far out of camber (and caster and toe of course) its become and guess what, NO WAY to correct it without adding $500-1000 worth of alignment adjustment gear.

- Or the classic.... twin charging the car then discovering that it still need to be tuned to take advantage of the new 21psi of boost AND, oh, it gets to 95mph righteously..... but don't stop worth shid.

For me, with every car I own, I make it a policy to drive it for several months or at least a couple thousand miles and then - and only then - can I make an educated change - IF and WHERE it may NEED IT.

The point is as N80 stated, modifications need to be well thought out and planned, not just to throw the "part of the day" at it because Freddy down the block just did so.

In addition to this, there ARE good, general modifications that don't necessarily require one to step on the never stopping mouse wheel.

- Sway bars - ALWAYS a good first step to suspension tuning and beyond them, there's no downside additions that need to be made other than to tune them to your driving environment, style, and abilities.

- Shocks - if you own an 03-04.5 Z33 with stock shocks, this is almost a given. Not only is the car getting old and the shocks likely toast, the first year (and half) cars had crap for shocks and springs. Poorly matched components with overdamped and just plain rude shocks with springs far too soft for the shocks. And you don't need to add springs if you don't want/need (or mild springs < 1" drop to maintain camber within range.)

And on and on. It's just important to "get smart" about modifications by reading and talking to people. There's FAQs here and on every other forum that will help guide one in making the right choices and knowing when and how to step off the treadmill of mods.

That is, if one takes the time to read them instead of just throwing out an open ended question without as much as 10 minutes of research. I see that pretty frequently these days and while I'd like to help any and everyone, there's only so many times one can say the same thing over and over ad nauseum.

[ Steps off soapbox ]



And wow, didn't even mention driving sch.... er, never mind...

terrasmak

iTrader: (8)

Camber if the angle of the tire. The more angle, the less if a chance it will rub. The rear of my car has pretty much been kept at -2.1 the whole time I have opened it.

N80, front has like maybe 0.2 adjustment. Rear has almost a full degree , but not each end of the range is limited by toe adjustment.

N80

Yep. The best modification you can make is to the driver. Track days are pricey but that's where I spent all my 'mod' money.

Track days are free now that I'm an instructor but any 'mod' money I can scrape up will go into safety equipment before performance mods. Seats, harnesses and roll bars are on my immediate wish list.

Camber arms up front would be next on the list. With proper track camber my Hankook RS-3s would last forever!

N80

So I'm ready to pull the trigger on a set of Hankook RS-4s when I found out they are a TireRack exclusive. Well, that ticks me off because I've got a local Discount Tire that I've done business with for 10 years. They can't get them. So I go to TireRack on line to order them. The size I want, which is the perfect size for me, is 265/40/18 (on Enkei RPF-1 9.5 +15 wheels). Well these are $20 more per tire than other sizes and backordered for the foreseeable future.

The 275/40/18s are available, have the exact circumference as the OEM rears, which I think are just right for the power band of the car, and they cost less. They also have the new Nexen track tires for waaay less, in the same size.

So I'm back to the "will they fit?" mode and "how much trouble am I going to be in if they rub?" mode with my next track day only 4 weeks away and the car going off to the shop for a week for a roll bar.

Anyway, the car is 10 years old and I've semi-gutted the interior already so I figure if the 275/40s rub I'll roll the fenders myself and give 'em a "terrasmak" yank if rolling doesn't do it. But, when I was looking at the front fenders today the lip underneath is not a flat 90 degree lip and seems to angle way up into the wheel well. At least one of these is not OEM and was replaced after my wreck at VIR. I think the other one was replaced in a fender bender. So they were not rolled by someone else.

This concerns me that there won't be much to "roll" on the fronts (From what everyone is saying, the rears shouldn't be an issue anyway.)

Can anyone confirm that this is normal for the lip in the front fenders or is this an aftermarket oddity.

Of course, it might be a good thing and they might not rub at all.

I guess the other question is, is there any chance that 275/40s won't fit up front even if I roll/pull the fenders?

MicVelo, when you had 275/40s on the same wheels, were there any issues with the fronts rubbing on the steering knuckle?

Also, MicVelo, was your rubbing an issue on the fronts or rears with the 275s?