yup. almost to the point of just getting a backup set of oem rays and running 305 DRs on them.

Well I have a 325 on a 10.5, that's only half an inch less (that's what she said) :eek:

Widening wheels?? :confused: That's crazy, it's cutting the wheel in half and welding in a piece of aluminum in between. This is highly unsafe and not recommended for anything other than show cars that don't actually move.

I'd definitely trust Rotas way way more than widened wheels hahaha

:iagree: Can't really get any better than Forged Rays :tup:

i have 18x12 +27 advan GT and it clears my sport brakes. i will be putting 345/35 mickey thompson street radial II on them

agreed. the issue is that with 19s there wont be the sidewall i was going for with 18s for the drag racing application intended.

granted any DR will be stickier based on the compound but more sidewalla would also help improve traction and my 60' times.

best was 1.950 on PSS's. would love to toss on DR's and hit 1.850 or 1.800

Anyone on here running a 285 35 19 on the stock rays? Just wanting to know if it'll fit without rubbing

you will be fine.

i got 305/30/19 rears no rub.

and if height is your worry, one time out of just pure need of tires for 2 weeks i ran 275/40/19 rears to get me by until my new ones came in. were fine as well.

sorry, not the rear, on the fronts, Im wanting to run a 285 bf goodrich rival for autocross up front but not sure if itll clear, I see someone running that size on a nismo rim but with the different offset I was a little concerned

oh christ haha thats a whole different case. 285 i believe is too wide for stock front rays. think 275 is about the widest you can go. i may be wrong.

I know itll pinch in, a 295 30 19 on a 9" wheel will work as well its just the clearance issue

yea idk.

im only at 265/35/19 up front currently

I see what you're saying, but if you need a taller sidewall why not run a higher aspect ratio like you did with the 275s. I know it will change your final drive going with a larger diameter but that could be a good thing at launching. Once the car gets going it won't really matter that you have a slightly taller gearing. I saw quite a few 295/40R19s at a decent price...however idk if the compound would be suitable for what you need it to do.

I run my rear fitment 285/35R19s on my front 9.5" Nismo wheels and they fit perfectly. I'm sure that half an inch less width on your wheel won't make a huge difference and it'll fit just fine.

What aspect 285 are you trying to run? The only issue I could think of could be the offset/rubbing issue...but if it does occur, that's not something a 5mm or 10mm spacer can't fix. I was skeptical too, thinking that if the 285s rub I'll buy spacers...so I risked it and it worked, no issues. I think it's worth a shot, especially if you have other wheels to drive on until you can get spacers. :excited:

:iagree:

That's where spacers come in if they have to.

285/35/19, its a kumho xs, which from my experience is a little wider and taller then most tires in the same size
I do have spare autocross wheels, I only throw these on and trailer the car to events, my only issue is the 12th im going to try and run and wont have spacers by then so I'll find out this week if it'll fit or not and let everyone know incase anyone wants to run that much tire.

What wheel is this on? 12" wide?

Yessir. 12 wide.

Does that push the car at all with 12" wheels in the back? What size front width are you running? Im torn this winter between doing an 11" or 12" setup in the back. I dont really want to run cambered at all and am trying to keep it all inside the fender with no poke as well.

I ran 19x9.5, -25, 275/35-19 PSS in the front and 19x12, -28, 325/30-19 PSS in the rear. Stock height, stock sway bars. It only pushed a little at the limit. Put the Hotchkis sway bars on, SPL front upper control arms, camber set to -2. It was tail happy when the tire got hot. About the 20 minute mark. Now with the 345's on the 12" rims. They poke. LOL Haven't had them on the track yet.

What do you mean by "push the car"

push, like is there too much grip that it over powers the fronts more than normal with the comparative front to rear surface area of tire. I am probably not explaining it right, but Rust in the last post seams to understand what im talking about a bit

But see, there is two things, that a wider tire doesn't really give you a lot more surface area because what it gains in width it looses in length (contact patch).

Also, a larger contact patch does not immediately translate into more grip, because yes, you have more compound on the road to grip, but because the weight is distributed, it gips less per square inch, if you know what I mean.

Easy example, a with a tire that has 4 square inches of ground contact and that is loaded with 1000lbs of the car's weight, you would have 250lbs for every square inch of the contact patch, and the more weight you have on a point, the more grip you will have.

Let's say you install a tire with twice the contact area, at 8 square inches, with the same 1000lbs of car weight. Now, each square inch only has 125lbs to carry, so less weight per square inch = less grip...however, because there is more surface area, it compensates for that difference, in physics, in a perfect world, it amounts to the the exact same grip either way.

The reason I use wide tires is because I like the look, and because there is less stress on the wider tire, so it should last longer.

understeer. Youre talking about understeer

Yea as soon as he explained it, I understood what he meant...It's understeer under power, and that is usually mainly due to the car's weight distribution. Like a rear engine Porsche for example is very prone to "push" because there is a lot more weight at the back and that gives the rear of the car a lot of traction. When you hit the gas in a corner, that rear grip and acceleration makes the front wheels get light (like a loaded pickup truck behind it's rear axle, it wants to lift the front wheels off the ground), and that causes the front to plow as you loose a lot of traction in the front tires when you take the weight off of them.

I haven't noticed a lot of "push" in the Z with any tire setup I've had on, some road conditions may sometimes encourage it, but the Z is just generally a tail happy car :)

Thanks for all the info guys. Definitely understand all the math parts (my major) you were explaining with per inch weight distribution and the understear. The only thing i dont grasp is the loss in length by going wider that you mentioned? maybe i just havent been awake long enough yet to see it though lol

edit: nevermind now i got it lol obvi the less per inch pressure doesnt cause the tire to flatten out as much shortening the contact patch.

Exactly, so it really seems that there is no advantage to going with a wider tire, or a bigger wheel/lower profile tire setup, even tests proove that all they really do is add more weight...thus making the car slower and less fuel efficient.

However, the difference isn't really big and most of us do it for the look/stance of the car. The other advantage though is that because you have a wider tire, it has more surface area, so you need less pressure in your tire to hold the weight of the car vs a skinny tire, so you can run at 30-34psi instead of 35-38 like some do, and that will give you a larger contact patch with the road because the tire will flatten out better, which is good for saving your tire under wheelspin and overall wear...because less weight per square inch = less stress / less heat and overall less wear on the tire compound, it would also help on the track, since the wider tire would build heat slower than a skinny one, giving you overall better traction after a few laps, since the skinnier tire would already be overheating and possibly disintegrating, while the wide tire would last much longer under similar conditions, and wear less over time too.

Attatched are two Images, the contact patch markings seen occured on my driveway after it rained.

These are from when I had my stock sized tires on my Nismo wheels, 245/40R19 front and 285/35R19 rear.

As you can see, the narrower front 245 tire has less width, but more length so that it looks more square.

The wider rear 285 tire has more width, but less length as it doesn't flatten as far due to the larger surface area it has it support it's given weight, and therefore looks like a rectangle. (granted, there is more weight on the front tires than the rears but I also run a few more psi in the front. I usually have them rear 34psi, front 36-37psi. Also, the car was on an uphill driveway with a small degree/angle, so there is a little more weight on the rear tires, and a little less weight on the front tires than usual)

Attachment 95441Is this meaty enough? MT slicks on the rear and runners in the front.

i want them lol :yum:

Man they hook up pretty nasty too!!

Nice, but think you have to do something about the wheel lugs though. :icon17:

Yea that's an old pic I have it studs now.

im guessing base rear brakes though :shakes head:

Yes base brakes. With stop tech rotors

wont work for me lol

sport brakes. my optins are limited.

i may just end up giving up the idea or just getting 305/35/19 MT ET street 2's

Here are some Continental ExtremeContact's for comparison.

275/35/19 on 19x9.5
305/30/19 on 19x10.5

http://www.the370z.com/members/jsutt...newwheels2.jpg

Looks nice, what are your offsets?

gussy were you able to use 370z base brakes? or did you have to drop back to the 350? 15" rim? im looking at getting a set of bead lock welds and running some M/T slicks but im still on the fence as to which brakes I can get away with using while doing it

run no rear brakes :stirthepot:

:bowrofl: