I know this has been asked for before, but we don't have it as a sticky thread in this forum. Can someone post up a Coupe wheel/tire fitment chart? I'm looking for 19" rims and need tire size dimensions to go with my rims. I'm getting confused because I've seen recommendations for 19x8.5 and 19x9.5 wheels as follows:

245/35/19 front and 275/30/19 rear

Not sure why the rear wheels would have a lower profile than the front to offset the 1" increase in the wheel diameter. Can someone explain? Thanks!


<font color=red>Shibal G-Thang</font color=red>
<font color=blue>'04 TB 6MT Graphite: Aero Pkg, Premium</font color=blue>

 

The stock 18" tire diameters with the Michelin Pilots are 25.8" front and 26.8" rear. The stock 18" wheel widths are 8.0" all the way around.

The configuration you've listed, with a Michelin Pilot, puts the front tire diameter at 25.8 and the rear at 25.7!

So you've done several things here. You've altered the rim diameter, altered the aspect ratios, altered the "width" stagger, and altered the "diameter" stagger.

Why anyone would want to do this? They looks, or they're going to be drifting or autocrossing, but of course if you were drifting or autocrossing I don't know why you'd go with a relatively heavier 19".

Also, by altering your "width" stagger by 1" (8.5 f 9.5 r) you are promoting more understeer.

When someone gives you a wheel recommendation, ask them why. We all have different missions we want to accomplish and your wheel and tire alteration is one of the most performance altering mods you can make.

Some that make that configuration probably have no idea why they did it, some think it looks good, and some want to alter the performance of their car by making a lower profile in the rear for less roll on the turns.

If you want to maintain the factory f/r diameter difference and diameter, you need to keep the rear at 275/40 (provided you want that 275 width and 9.5" wheel width) in the rear which in the Bridgestones will put you at 26.6" in the rear. Not exact but close enough probably to keep your VDC working. The Michelin Pilots don't come in a 275/40.

BTW,
Toyo Proxes T1s come in a 275/40 and puts the diameter at 26.5".


2004.5 Coupe/5AT/Ivory/Everything but front spoiler/Nismo CAI/Crawford V5

 

great explanation but for 19"s, you'll need 245/35 and 275/35 to maintain the correct stagger. The 40 series would be for 18" applications.

Also, going to an 8.5 and 9.5" width won't necessarily increase understeer by a noticeable amount. You have to remember that the stock configuration has the a 10 and 20 mm difference in width (17" and 18" stock respectively). The benefits of having a bigger footprint in the rear (30 mm in our examples) to help fight the inate power oversteer might be worth the 'extra' understeer' that comes with the additional 10 mm difference.

 

245/35/19 and 275/35/19 are ideal for 19x8.5 and 19x9.5

Russ

Black 6MT Coupe
Jax, FL
G35Driver.com Business Cards

 

Well, width of the rim should be chosen base on the size of tires you want to run. If you are buying rims for performance, I'd get a lightweight 18" rims with decent tires. 19" would work as well, but you'll have harder time with the ride quality and more expensive tires. I wouldn't go as far as using equal size tires front and rear, but I wouldn't add more to the understeer nature of the car either.

My recommendation would be to run wider tires (maybe 245/40R18 + 265/40R18) on lightweight 18" rims for maximum performance. This set up will do these things for you:

1) Increase footprint on the car, Thus increasing grip
2) Effectively lower your car by a small amount without having to change out your suspension. Rear is dropped slightly more than the front. (mild mild less understeer)
3) Won't affect ride quality so much, if you are using these as your daily wheels as well as track wheels.
4) Maintain staggered configuration.
As much as I appreciate the attempt to reduce understeer by using same size tires, I'd rather leave the staggered configuration alone and use sway bars to reduce understeer.


We all know 19" looks better than 18", but performance wise it might not make sense. I know the difference is only a couple of pounds, but that adds up to 80-100lbs of unspring weight when it comes to performance. However, going from stock 18" to aftermarket 19", you are actually still shaving good amount of weight. Of course, you'd be shaving more weight if you go with 18" aftermarket rims.

 

al, suk, trenta, great points.

I was actually considering going with the 245/40 265/40 route on Nismo 18"s. Going to a 275 in the rear will force my hand to the Toyo Proxes as the Pilots aren't available. I think this is a great combo on a 8.5f 9.5r width. Lightweight, keep my tire pressure monitor, keep a good light tire. Zing!

2004.5 Coupe/5AT/Ivory/Everything but front spoiler/Nismo CAI/Crawford V5

 

Say I wanted to go with a light weight 18" set of wheels.

would it make more sense to go 18x9 all around and just stagger the tires (just like oem setup)

and even if you want 19", why would you want to stagger the wheels (8.5f, 9.5r) instead of 9 or 9.5 all around and stagger just the tires?



btw, what choices are there for 18x9, 18x9.5, or 18x10 light weight wheels?

 

It's all a bunch of trade offs. If you stay with same wheel widths, you will have similar steer bias as stock. Wider and bigger means more rolling resistance, but larger contact patch. More stagger means more understeer. Different tires accept different wheel widths. For example the Dunlops seem to run on more narrow tires.

Go to tirerack.com and click on a tire then click the Specs tab and you'll see what I mean. There is an acceptable range and a "tested" width. You can still stagger with equally wide wheels. You can stagger more with staggered wheels, to a point that the fender will rub.

It's not easy! I've been agonizing over this for over a month. I've decided to stick with 18"s, now I just can't decide how wide I want everything.

2004.5 Coupe/5AT/Ivory/Everything but front spoiler/Nismo CAI/Crawford V5

 

I would recommend some 18" quality forged aluminum wheels that weight less than 18lbs. (Volk wheels are very good, but also expensive) Personally I have been looking into the following:

Rays 350Z Track wheels - around 18lbs (Cheapest. but look like 17" )
Nismo LMGT-4 18" - around 18 lbs (Nismo, looks pretty good)
Volk LE37T 18" - around 18lbs (My favorite 6 spoke design, proven)
Volk CE27N - around 17lbs (very light, design matches G35C well)
Gram Light 57F - around 17lbs (very light)

btw:, all of these wheels cost in the vacinity of $2000 without tires. So this is a $3k investment.

IIRC the stock 18" rims on the coupe weights alittle more than 24lbs. When you go to a 18" rim, you are shaving 6lbs per rim, which is 24lb per unsprung weight all around.
Btw: to correct my statement above, unspring weight doesn't really have any 1:10 ratio in terms of real weight reduction, maybe 1:4 ratio. (Grassroot magazing did a test last year)

 

Wow... Thanks for all the replies. My reasons for going 19" is to improve the look of the car. I'm not too interested in racing, but may sign up for an HPDE course to learn proper performance driving techniques and gain greater respect for my car. I've been looking at a few rims and tires. Here's my current lineup. Any comments would be appreciated. I'm looking for a balance of looks and performance and not extreme on either end.

Choice #1: (Not sure which offsets to get)
-5Zigen Hyper 5ZS 19" in Super Metallic Black (Black Chrome)
-Front: 19x8.5 with Toyo Proxes T1-S 245/35/19
-Rear: 19x9.5 with Toyo Proxes T1-S 275/35/19

Choice #2:
-Advan Model 5 19" in Chrome
-Front: 19x8 with Toyo Proxes T1-S 245/35/19
-Rear: 19x9 with Toyo Proxes T1-S 275/35/19

Choice #3:
-Nismo LMGT4 19" in Silver
-Front: 19x8.5 with Toyo Proxes T1-S 245/35/19
-Rear: 19x9.5 with Toyo Proxes T1-S 275/35/19

I'm still up in the air about offsets. I read a quick faq about what they are, but not too sure about what going extreme with offsets will do to a car. Clearing the brake calipers is one thing, but I've heard some performance degradation or uneven tire wear can occur with going with out of spec offsets. Let me know what you guys think about my choices.

Thanks!

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<font color=blue>'04 TB 6MT Graphite: Aero Pkg, Premium</font color=blue>