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Discussion Starter · #1 ·
Folks, I've read threads on this topic for a long time on this and other boards, but have not yet been convinced of the truth. I want to use 255/40 rubber on 8.5x18 wheels on all four corners of my daily driver, this to balance the handling, reduce tire wear/feathering, and keep the wheel/tire size more appropriate to the power level of the car. I have an Enthusiast, so no VDC but it does have TCS.

My question is: will the TCS or braking be negatively effected because there would be no rpm differential between front and back wheels? If not then I'll probably go with the setup mentioned. If yes, then I'll go to 245/40s on the front and give up the ability to rotate front-to-back. Who has done a non-staggered setup and lived to tell about it? Thanks for your help!

Another advantage of 255s all around is a reduction in rotation weight, even when going to 18s. The factory tires weigh 28/29 lbs each, while 255s (Goodyear or Goodrich for example) weigh just 26/27 lbs. Michelin PS2s weigh just 24/25#. By reducing the weight out at the circumference of each wheel I hope not to lose as much acceleration, even though the weight is concentrated further from the hub. While they look cool, the popular 275s aren't needed for traction on a nearly-stock Z. Heck, I run 275s on my 400 HP pickup with a 60/40 weight bias. :irock:
 

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I don't know if this will help, but it might provide a little insight into the TCS or VDC issue.

I have different brand tires between the front and rear. At first, my VDC seemed to act up on it as I would take long curves and the ABS would activate. Now it doesn't do that.

Oh, and I have the staggered tire setup on my 18x8's.
 

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Discussion Starter · #4 ·
Thanks for the link - really - but I read both parts of that series when it first came out in print, and it was one of the primary drivers in my desire to try going non-staggered. The problem is that the article does not answer the question - will the TCS or braking be negatively effected on a daily driver?. They mention the potential negative effects on the VCS, but their car hasn't got VCS anyway so they don't even really know what happens. That was a project car interested only in the magical 1.0g on a skidpad, not a daily driver. The article doesn't even mention braking performance - I wonder why?

Hey, I'm not being critical of the help here - thanks to everyone who has or will contribute. I'm beginning to think that no one knows the answer for certain. :dunno:
 

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I think you will be a pioneer, but this is my thoughts:

1. why would braking be changed? almost all of the braking force is put on the front tires. As long as the front tires are sufficiently grippy, I dont see any problems with braking ever.

2. the VDC is touchy when it comes to changing tire sizes. It is the diameters that matter. I know some people have swapped to 19" and put the wrong size on the rear only to have problems. I cant speak for the TCS, but this should be noted.
 

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Discussion Starter · #6 ·
Some owners have stated that they have run without stagger and not had problems, others say they tried it and had issues. The braking might be affected because the rear wheels will be turning faster than the system thinks they should be turning, mimicking the wheel not braking as it should be. This may affect the brake's proportioning balance, putting too much force on the rear brakes risking locking them up....not a good thing, particularly when running on the traditionally wet Golf Coast roads. Or it may not happen at all - but the possibility does exist.

Since I don't have VDC I don't care, although it makes sense that the system would be affected. I can always turn the TCS off, but there are times when it is needed. I am very much appreciating the help guys! :biggrin:
 

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I help where I can. Been on these forums for almost 4 years now, and this topic is rarely if ever discussed.
 

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It surprises me no one has a list of workable combos. The setups people have told me worked for them are:

225/50-17f x 235/50-17r Stock
245/45-17f x 255/45-17r
225/50-18f x 245/45-18r Stock
245/40-18f x 275/40-18r Nismo recommended size
275/35-18f x 275/40-18r

I am sure others have more combos that don't upset the VDC/TCS and are available (unlike the FAQ at 350zmotoring that has a bunch of imaginary tire sizes that nobody makes).


Got Rpm, yesterday on the 350zmotoring board there is a guy who is running front 245x35x19 - back275x30x19 and said "my slip ligth come on some times even when i an going straight or makeing a turn and not at high speed" in an Enthusiast (the post itself does not say it is an Enthusiast but I searched back though his post and found where he had stated his model).

Obviously with that combo his back tires are actually smaller in diameter than the front by just a bit but I have read of others that are running same all the way around and still having issues with high speed turns.

Tony at Performance Nissan recently posted a shot of Andy's car that is running 275/35-18F and 275/40-18s on 4 rear Nismo wheels. I know you think that is too wide, and I know it can't be rotated front to back but it's cool that all four are the same width. If I was going with 18s I would probably consider this setup as one of my options.

Chris
 

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For what it's worth, I'm running the following with awesome results:

F: 245/40/18
R: 265/40/18

No issues with VDC, Anti-lock braking, or SLIP light.
 

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I'm not sure I can give a "definitive" answer but I have been running 245x45x18's all round for the last 6 months or so with absolutely no problems what so ever!

Hope it helps

As always

H
 

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Discussion Starter · #11 ·
Thanks for sharing guys. Harry, as I said above I've read hundreds of posts online and have read of others running the same tire on all four - most say it's 'okay' but there have been a few who say they have had trouble; that's why I hoped to get more answers with enough information to clarify the issue. What Z do you have, base, enthusiast, etc? Do you turn off the TCS?

I can understand why there could be problems if the rear tires are smaller than the fronts, and also why all four tires the same could confuse the VCS. But the brakes and TCS are the questions for me. Does the TCS even monitor the front wheel speeds? Why would it if all it does is brake the spinning drive wheel and/or cut fuel to one or more cylinders. Other automakers TCSs only monitor the drive wheels AFAIK.
 

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I wish I knew more about TCS as well.

From what I have ascertained from driving the car and what people have said on line, the TCS uses the ABS wheel sensors to determine rotational speed of all four wheels. The computer then compares the speed of the back tires to that of the front to determine if the backs are spinning.

For example, if the fronts are turning 804 revs per minute and the backs 792, it would calculate based on the diameter difference that all four wheels are traveling at 65 mph. If the fronts are turning 804 and the backs are turning 810, it would think the backs are sliding. The question is where is the tolerance.

In Harry's example (and from what I remember, he has a Track model) all four would be turning 778 at 65. Apparently this is not causing his computer to think the backs are sliding but I have read where others went the same size all the way around and had problems.

What amazes me is there is no adjustment. How hard would it have been for Nissan to add some logic to the ECU so that when it is reset it recalculates the rotational speed of the tires and then remaps the difference? Then again, maybe it does and nobody has tried that.

Anyway, this is a great topic, I just wish there was more information on it.

Chris
 

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Discussion Starter · #13 ·
I found that in the FSM it says:

TCS Function
 The wheel spin occurrence of the drive wheels is detected by the ABS actuator and electric unit (control unit) using the wheel speed signals from all four wheels, so when wheel spin occurs, the amount of wheel spin is reduced by controlling the hydraulic brakes on the right and left rear wheels, cutting the fuel to the engine and partially closing the throttle valve to reduce the engine torque. The throttle opening is also controlled to obtain the optimum engine torque.
 Depending on road circumstances, the driver may have a sluggish feel. This is normal, because the optimum traction has the highest priority under TCS operation.
 TCS may be activated any time the vehicle suddenly accelerates, suddenly downshifts, or is driven on a road with a varying surface friction coefficient.
 During TCS operation, it informs a driver of system operation by flashing SLIP indicator lamp.


That answers a few questions, but not the rpm tolerance - there must be some tolerences in the allowable rpm differences. On another board two posters who run non-staggered setups say the TCS comes on regularly, in one case virtually all the time. Yet, a few like Harry say no problems.....how puzzling.
 

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Down here we only get two types, the Track (which I have) and the Touring.

To be honest, I rarely turn the VDC off. The only time I do is when I "know" I need to, if you know what I mean.

The only time I ever get interference fron the VDC is when I know it is going to happen, it still pisses me off though!

Hope this helps.

As always

H
 

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I've been running a non-staggered set-up for about 2 years now. 1st 255/45-17's, then this year, 255/40-17's. The TCS does kick in more with these set-ups, more so with the 40 series tires. For normal driving, it's not a big deal, but it sucks having NO power exiting turns. When I track my Z, I always turn it off anyways.

As to any effect on braking, I haven't noticed any ill effects.
 

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I have a friend who runs the same sizes at all four corners when using the car heavily at the track.

He reports having zero problems. And prefers the setup for track driving.

Since the ABS is reading wheel speed, I don't think it will be thrown off.
 

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How about staggerd tire sizes for a set of 19'S 245-30-19 front 255 -35 -19 for the back you should not have problems with this set up {Buddy works at townfair tire} :shiftdrive:
 

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Anyone interested in this?....

From the article: "...We found, conveniently, that the rear tires Nismo uses on the Z--275/40ZR-18 BFGoodrich g-Force KDs mounted on 18x9.5-inch wheels with a 30mm offset--actually fit the front perfectly.

There's a tire shop local to me selling "take off" wheels by the pair. The listing is on Craigslist bay area. search for 'take offs' in the auto parts section.
 

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Discussion Starter · #20 ·
After several days of comments on two boards, it appears that the answer to my question is no closer to being realized.
  • Some owners report running non-staggered setups without problems
  • Some owners report TCS issues with non-staggered setups occasionally.
  • Some owners report TCS issues with non-staggered setups all the time
Almost no one has reported if their TCS is kept on or off - that would solve the problem, and this explains why those who track the non-stagger setup seldom report problems. If the TCS is turned off no wonder there is no issue. I discount second-had reports - first-hand reports are contradictory enough!

One parameter we have not addresses are the years involved. Perhaps some years have different software and will allow non-staggered setups. It is no surprise that reverse stagger - smaller rear diameters - cause problems. Thanks everyone for their input in this thread, maybe some day we'll find out the whole story.



"...the rear tires Nismo uses on the Z--275/40ZR-18 BFGoodrich g-Force KDs mounted on 18x9.5-inch wheels with a 30mm offset--actually fit the front perfectly....There's a tire shop local to me selling "take off" wheels by the pair.
If I understand this poster, he is recomending going to a tire shop to get the NISMO wheels as take-offs. The NISMO wheels referenced are the aftermarket variety at ca. $500 a pop, and not many of them will ever be discarded at a tire shop.....unfortunately. :pepsi:

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