BAEZ

Based on this Todd then I have a question for you. Seeing that you say that Nissan is looking for a .5 to .75 stagger front to rear (and later in this post you say you do not have documentation for that because I wish I could find where Nissan says that) then why does NISMO call for this tire set up 245/40/18, 275/40/18 on the 18" NISMO wheels? That is an inch stagger front to rear. Is it becuase they follow it up with a disclaimer saying that these wheels and tires are not for VDC cars? Or is it because it keeps the speedometer pretty close to right on? I have a Performance model and have considered buying the NISMO wheels but I want to retain the VDC. I am very curious about what my options are. Now I have also heard that if you buy the NISMO suspension with the NISMO wheels then you are okay? Confusing to say the least. The only thing I can figure from that comment is that because you have now lowered your Z 3/4 of an inch with the NISMO suspension then maybe you can run a different tire set up on the NISMO 18" wheels. For instance how about 255/35 front and 275/35 rear. See I figure this way you meet the rule you mentioned because this is only a .6 stagger. But because this tire sizing has a .5" lower sidewall then stock, the car all together will be lower but the gap between the tires and the fender will increase. But then the NISMO suspension should cover that by lowering the car 3/4 of an inch. I am curious to recieve any feedback on this long AZZ post. Thanks. Z ya!

NismoGCoupe

well what happen with me was about the first 10 miles on the tires I got constant slip if I excelerated to hard, but the reason for it was because the tires had some type slick layer on them which was causing it to slip, but it eventually wore off

NismoGCoupe

I figured maybe it was doing the same thing for you but by 200 miles it should have woren off. Hey you can always try smoking the tires take some real tread off them

james007p

well now what i'm driving with the TCS off all the time, i can do that. but the more tread i burn, my rear tires will be getting shorter and shorter than the front.

Todd@ProDyno

I'll add more later, but here are my initial thoughts.

first, nissan said .4 to .8" but said a lil more varience 'should' be ok. Maybe they think 1" is acceptable.
Second, Im sure going up to an inch in stagger with the 275-40-18 is more acceptable since the rear tire is the exact same overall diameter as a stock tire.
3rd...I have no clue how Nismo suspension all of a sudden makes it ok to use this size on a VDC car. That blows my mind.

Im thinking fast now on the way to a meeting, Ill be back shortly

NismoGCoupe

honestly I dont see how its the tire size being the problem I've so many people with the same setup as you and havent had any issues with the slip coming up, I've even seen people running the same width all the way around with out a problem

james007p

so what else could it be? it only started happening when i put the wheels on.

NismoGCoupe

I dont know did you make sure you put the wheels on the right side that may cause a problem if tread is not traveling the right way it may not grip and upset the vdc

james007p

my car doesn't have VDC (i have a touring roadster). on the right side? are you saying that one of the 275x30 is specifically for the left rear?

NismoGCoupe

Yes mostly this is your problem, look around at the inside sidewall there will be arrow showing which way the tread should travel make sure there facing foward

james007p

i'll check that but i had a professional place put them on for me. i'm sure they would know about that. besides, the lettering and tire size info is only on one side of each tire i believe, and i know i see the letters.

BAEZ

First of all thanks for replying so quickly. I am not so sure I agree with 1" being acceptable but I have read post where people have put the NISMO wheels on a car with VDC and say they have no problems using the NISMO recommended tire sizes. However, I am inclined to agree with your second comment about the 275/40 being acceptable because it is the exact same size as the stock 245/45. But then lets not forget that didn't NISMO say these wheels were NOT for the "VDC" cars? So I guess 1" doesn't matter then. As I have buddies with the Base model and they have some crazy wheel tire set ups that work just fine. I am so confused. 3rd...re read my post about why I think the NISMO (or any suspension upgrade where you lower the car) would allow you to use tires on the NISMO wheels that would get you in the right stagger. Do you see any problems running a 255/35-18 on a 8.5" wheel or a 275/35-18 on a 9.5" wheel? The only problem I can come up with would lie in the gap between the tire and the fender getting bigger. But then lowering the car would resolve this??? Thanks and I am looking forward to getting this figured out. I think I can get my dealer to make me a great deal on the wheels and then you can hook me up with some tires once we get this figured out. Z Ya!

Todd@ProDyno

well, I dont think yoru theory on gap and suspension has anything to do with this. The reason the stagger has an effect on vdc/trac/abs is because the ecu expects at 65mph for example, to go through 779 revolutions per mile rear , and 800revs per mile in the front, but in reality if you have a shorter tire on, it turns 815 revolutions per milerear and 807 front, it confuses the computer. When you think of it like this it doesnt seem like such a little difference would do anything. But if you know anything about these ecus, you know just how sensitive they can be. if nissan set the mathmatical graphs up to have only so much tolerance difference, and its beyond that...then the vdc and other functions will be adversly effected.

It blows my mind trying to figure out why Nismo would make that suspension statement when in reality theres no way that would effect those systems. Sales tactic?

BAEZ

I think you misunderstood my post. I do not think that the suspension and gap have anything directly to do with keeping the VDC in tact. What I was suggesting was that by installing the suspension and lowering the car you could go with a lower profile tire. Thereby based on tire specs you could get a set up on an 18" wheel that met the tolerance for the proper stagger. However, you have now introduced another aspect to consider. Is that how the VDC works? Off the revolutions per mile? Yeah I guess that makes sense. Okay then if I go with again this tire set up 255/35/18 (833 rev/mile) on front and 275/35/18 (814) don’t I keep that relationship in tact for the VDC? The difference in revolutions per mile with the stock set up front to back is 24 more revs per mile in the front. With the NISMO suggestion this difference increases to 36. With the tire set up I am suggesting it goes to 19. These relationships are directly proportional to the differences in diameter. So with all that said I guess my bottom line question is if I go with 255/35/18 on the front and 275/35/18 on the rear will it affect my VDC??? Z Ya!

Todd@ProDyno

you may be within spec f revs per mile front to rear with your new combo. However, the 275-35-18 is 1.1" shorter than the stock rear. So the ecu is still expecting 780rpm, but is now getting 813rpm. This is the other half of the equation which I guess I wasnt clear about above.

The traction systems will be effected by both overall diameter change, as well as stagger change.

So...even if you are able to keep the EXACT stagger difference .71" front to rear (track model), if you change the overall diameter significantly, the computer will still have no idea what its doing.

Todd@ProDyno

yup

bwzabodyn

iTrader: (2)

To end all discussion, it has been proven that the best tire setup for the Z/G in 19x8.5 and 19x9.5 is 255/35/19 front and 275/35/19 rear - period! W/ Toyo T1-s tires, the stagger is 0.6" from front to rear (looks better than the 245/275 combo) & the front tires protect the rim better than the 245/35.... the only problem with this is that there are currently only three or four tires to choose from that make both of these sizes (but two of those include the Toyo's and GoodYear Eagle F1 Gs-D3's - IMO the best street tires available).... this discussion will go on and on, however, and no solution will be reached until WE (the owners) start voicing our opinions by buying the correct tire sizes....

NismoGCoupe

just because you can see the lettering on the tire doesn't mean that there on the right side, you can still have them on the wrong side and see the lettering its all on which way the tread is facing
just look on the sidewall and make sure that the tires that say left are on the driver side and the ones that say right on the passenger side

mmagnus

I have been having the same problem. I installed 245/35/19 on front and 275/30/19 Toyo TS1 tires last week. Anytime I make a turn at a slight speed, the TC was kicking in. I called America's Tire today and explained to them the issue, they said no problem bring it in today and we will swap out for a new set of Yokohama
AVS sports. No problem.

Cudos to the guys a Americas Tire in Walnut Creek, CA. Great bunch of guys.

Mark

james007p

Consider yourself lucky.