Can I modify tire sizes??

Shocks, springs, sway bars, coliovers, bushings, brakes, wheels, tires - This is the place to discuss G-Series suspension modifications!
diitto
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I have a 2006 G35 Coupe 6MT (19" sport tuned suspension) with rear tires that are 245/40/19 and front tires that are 225/40/19... Are there any reasonable options where I could make the front and rear tires both the same size, as an obvious example, split the size difference and make them both 235/40/19... I would like to do this so I could rotate tires, front to back.. Could the fronts tolerate being slightly larger like that??? What problems might this cause??? I understand the speedometer would be a percent or so off if I made a change like described above (when speed reads 60 I would actually be doing 59.3 instead)... What about the odometer??? Would that be slightly off as well??? I've never had a car with a staggered fitment before so this is all new to me... Any help would be much appreciated... thanks... bob...


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Slider4105
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Well you have to figure your car also comes with non staggered wheels on different models, so yes you can run non staggered sizes. Changing to a different size will effect the odometer reading just like changing the actual speed your going because you're going to a different size tire. How much I don't know, and I don't exactly know what size tire you could put on. But you also have to remember that not only are the tires sized differently, so are the wheels. My guess is MAYBE you could run a narrower tire on the rear wheels with a little stretch, but I really don't know.

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C-Kwik
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It would be likely that your VDC would go haywire. I've seen it before in a Z that had some aftermarket wheels and tires. They were still staggered, but the diameters weren't staggered by as much as the OE wheels. The VDC detected slip anytime you moved and even worse when you pressed the brakes.

BippuBoss
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its hard to say what can happen, but as long as you keep the tire diameter the same. there are tire and wheel calculators where you can figure this out. i use tirerack sometimes. what i've done for myself is figure out the stock tire size and then get as close with tires as possible. if you go +1 for wheel size the sidewall is going to change. it's a give and take when it comes to this sort of thing. i'm just going to give a quick example that probably isn't right but for instance, if you have a 225/40 and they are say either 8 or 8.5 inch wide wheel you could run 215/35 or 40 with 19 or 225/35 19. the variations you can do are insane. and also if you go wider the sizes will change. if you know the wheels you are going for you can ask the manufacturer what sizes will work and things of that nature.

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Sentientbydesign
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You bought a 6-speed sports coupe with sports suspension and lightweight staggered forged rims and you want to WHAT???

Rotating staggered wheels is definitely not recommended. The actual wheels are .5" different in width front to back.

Your best bet is to get some Kuhmos and get your suspension to be tuned as conservative as possible.

joe603
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I understand you want to go with the same size...not sure how the VDC will react to that...probably not good. However, I do know that if you wanted to go wider you can.

I'm running 245/35-19 front and 275/35-19 rear and have no problems with the VDC.

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Sentientbydesign
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Couldn't find the thread I was looking for, but Kenrik's works too.

Read the whole thing...

http://forums.g35club.org/zerothread?id=267932

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hernandez5749
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you can modify the sizes but only if you have the same size rim on all 4 corners. Since your car came with the factory 19's you are running a staggered setup with 19x8 front and 19x8.5 rear. myself i'm tryin to run a 19x10 or 20x10 setup so i can do the same thing that you're trying. Rotating tires is such a cost saver in the long run. As long as you verify the offsets and remember if you have the brembo kit or other big brake upgrade you have to factor the offset you'll need to clear those calipers. With whatever size rim setup you run, you're gonna need spacers in the rear so that the wheels lineup accordingly. Otherwise if you stand in the front of your car and look down the line at the wheels you'll notice that the rear wheels will be more tucked in than the front. In all cases good luck to you since i'm tryin to do the same thing and happy hunting....

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C-Kwik
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Problem is, the G35 coupes stagger the width AND diameter of the tires. The VDC could care less about the width. The VDC will detect a change in the ratio of the diameter between the front and rear wheels and believe one axle is experiencing a loss of traction. This is what triggers the VDC with improper tire sizing.

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Sentientbydesign
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C-Kwik wrote:Problem is, the G35 coupes stagger the width AND diameter of the tires. The VDC could care less about the width. The VDC will detect a change in the ratio of the diameter between the front and rear wheels and believe one axle is experiencing a loss of traction. This is what triggers the VDC with improper tire sizing.
How does this work with the 17" rims? My understanding is that they are the same height all around. Maybe a different VDC setting?

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hernandez5749
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good point but i only have a question - will the VDC go off like you say if the rims and tires are all the same size on all four corners? That at least is my curiousity due to the fact that is what i'm trying to do with my coupe. I love the idea that i'll have a deep lip all around, will be able to rotate which will save me money on tires in the long run, the car will have awesome traction all around, plus when i think of it, i know it'll just look sweet.

p.s. im goin for the 19x10 / 20x10 setup.. 3 in lip or more if possible

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hernandez5749
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i think that if i go with a plus 22 offset all around the car i should be fine. Probably most likely still use a small spacer for the rear wheels just to line'em up with the fronts and roll the fenders all around and it'll be sweet. What do you guys think?

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Sentientbydesign
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The coupes are offset in height front to back regardless of rims size. The VDC will likely start tripping out when you plug the same height tires on the front and back.

It might be a good idea to check with the dealer to see about modifying the front to back ratios.

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hernandez5749
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how do u kill the VDC?!?!?!?!?!? in the case that i do setup my wheels like how i wanted 19x10 or 20x10 all around with the same tire size. If that stupid VDC starts acting up after the change im gonna rip it out. I never ever use it, i can use the space to put a nicely concealed switch for whatever i feel like putting there. someone please help......

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hernandez5749
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anyone know anything about the tanabe pro5 coilover kit. i got a g35 coupe with eibach sportline springs, sways, front n rear kinetix camber and toe kit, stillen front n rear struts.

im considering 19x10 or 20x10 rims with a 20-22plus offset. most likely would have to throw a spacer in the rear just to line up the wheels. plus im rolling my fenders.

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Sentientbydesign
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Honestly bro. I wouldn't do the same rims all around. We've all been trying to tell you that and you don't seem to care, so I'll just give you the info you're looking for.

There's a company online that sells a VDC "permanent off" switch. Not only will your VDC not work, but your ABS won't either. The ABS monitors the speed sensors at all 4 wheels. If you brake and one of them stops spinning while the others are still spinning, then it will modulate pressure to that stuck wheel to get it to unlock.

I can't say that running the same size front to back is going to trip it out enough for regular driving, but I'm almost sure it will make emergency braking unsafe.

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hernandez5749
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then i can't understand how in a performance mag (i think modified, but definitely not super street) there is a white g35 coupe with 18x10's advan rims getting prepped up for track use. someone please explain this to me..... they're running 265/40r/18 tires. its got gtspec underbody braces (one being a 4pt brace in the middle which looks pretty sick). i do appreciate all of the info from everyone, good n bad.

question : is there a way to modify the VDC, through the ECU? just curious....long live the G

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hernandez5749
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i would really like to know how the VDC would determine a difference in tire size if when the g35 comes with 17in rims and all the tires are the same size? someone let me know about this im dying to make a decision on which rims im gonna use for my setup.

i wanna go with 19x10 or 20x10 with 265's all around.


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Sentientbydesign
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The 17" rims actually have two different tires sizes per Tirerack.com.

The front is a 225/50/17 the rear is a 235/50/17. The difference in radius is around .21" on the 19" rims it's closer to .31"

If you go to tirerack.com they specify a 9mm radial difference when going with a 20x9 all the way around.

I would contact your local dealership to see if they can modify the VDC to have the front and rear ratios the same.

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hernandez5749
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thanks alot for the info im gonna see what they have to offer. have a good one


G35200687
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I have a 2006 Infiniti G35 coupe, rear wheel drive and I am wanting to get rid of the staggered rims. I am looking at putting the front size which is 18 on the back as well, so I can rotate and get a longer lasting tire. I was wondering if that idea is something that is OK to do to the car, or is it something that you should not do?
Last edited by Rogue One on Fri Sep 18, 2020 3:12 pm, edited 1 time in total.
Reason: TYPO

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Rogue One
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G35200687 wrote:
Fri May 08, 2020 1:47 pm
I have a 2006 Infiniti G35 coupe, rear wheel drive and I am wanting to get rid of the staggered rims. I am looking at putting the front size which is 18 on the back as well, so I can rotate and get a longer lasting tire. I was wondering if that idea is something that is OK to do to the car, or is it something that you should not do?
:welcome:

Sorry for the delay in responding. I've merged this with existing topic. If you read the previous posts you'll find the answer you're looking for.


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