Throbber

I spoke to my brother over the holidays and he said that his company can purchase wholesale from discount tire. So I have been browsing the wheels and tires and here is what I came up with. I was going to go with 18's but since I could get 19's for the same price using his discount I'm looking at 19's.

I am however having a hell of a time finding tires that match up with the stock specs. I don’t want to put a 275 on the rear because the car has a tendency to understeer already. I will be increasing the fronts to 245 with a 255 on the rear. Which keeps everything pretty close to the stock setup other than the obvious width increases.

What I wanted to know is it ok to go with a 35 aspect ratio in the front and a 40 in the rear? Will it look silly? What kind of effects will it have on the ride???

Here is the specs on the wheels and tires setup:

-Front Wheels
19 X 8 +35 5Zigen 5ZR Copse 1-piece Hyper Black
Tires
245/35ZR-19

These numbers came from http://gs.tolan-hoechst.com/tirecalc.htm
The first number is stock then planned (stock / planned)

Tire height (inches): 25.97 / 25.75
Ride height difference (inches): -.011
Tire width difference (inches): .79
Tire rollout (inches): 81.59 / 80.9
Wheel/Tire Aspect Ratio (%): 90 / 82
Wheel diameter difference (inches): 1
Wheel width difference (inches): 0
Wheel offset difference (mm): 5
Wheel Inboard increase (inches): .196
Wheel Outboard increase (inches): -.196
Tire-Wheel Inboard increase (inches): .591
Tire-Wheel Outboard increase (inches): .198
Effect on tire track (inches): .4


-Rear Wheels
19 X 9 +35 5Zigen 5ZR Copse 1-piece Hyper Black
Tires
255/40ZR-19

Tire height (inches): 26.68 / 27.03
Ride height difference (inches): .175
Tire width difference (inches): .39
Tire rollout (inches): 83.82 / 84.92
Wheel/Tire Aspect Ratio (%): 82 / 89
Wheel diameter difference (inches): 1
Wheel width difference (inches): 1
Wheel offset difference (mm): 2
Wheel Inboard increase (inches): .578
Wheel Outboard increase (inches): .421
Tire-Wheel Inboard increase (inches): .733
Tire-Wheel Outboard increase (inches): .616
Effect on tire track (inches): .23


Thanks for your advise......

Brad4rdHay

The car comes with a slightly staggered diameters front to rear...the rear being a tad larger overall. Could be because they just wanted to order all 45 series tires...i dont know.

Driven

No, No, NO, NO, No, NO, No, NO!!! When you see your first Z set up as follows...you'll be kicking yourself in the head.....really!

What you want is this....fist make a commitment on either the 18's, or the 19's and move forward. Base that decision on how rough your roads are and weather you do a great deal of curb parking. Don't put a wimppy 255 tire on the rear either if you know what is good for you. Put at LEAST a 275/30/18 out back and match her up with a set of 245/35/19's. My next comment is on your offsets.....NONONONONONONONONONONONONO! Unless you want your tires to look tucked like taht all the time? If you are going to spend money on making your car perform better....wouldn't you naturally want to improve it's looks at no additional cost? Yes? Well, then, you need to do more research on available offsets. Are these 35mm+ offsets all the way around the only options? If so...and it were me...I'd walk away and look for another wheel. If you truely want a 8 and 9" stagger I would go with the tire widths mentioned abouve and would run a 25mm+ on both the front and rear. If this isn't an option..I'd shoot for damn close. You will be happy

D'oh

Hmmm...

I disagree with Driven on the rear tire assesment. IMO, the car is already rear biased by quite a bit, so I would not want to go to 275's unless I was to also go to 265's in front.

I personally plan on going to 245's all around, with the standard 245/45 in back and a 245/40 in front to maintain an overall tire size relatively close to stock. My personal goal is to reduce understeer while keeping everything else totally stock so I would be in a stock class for SCCA type racing. I'm hoping that larger front tires would help a little with that goal.

If your goal is different, then Driven's advice might be much better for you.

Either way, I don't see a problem using tires with different aspect ratios from front to rear.

-D'oh!

rodH

iTrader: (2)

I plan on going 19" and the sizes usually given are 245-f, 275-r, BUT I also fear that that will make the relative understeer worse. The 245-f, 255-r actuallly sounds like it could be a better idea (for PURE performance reasons) than the 275-r. I wouldn't like to run different aspect ratios, BUT when you think that in reality the 255-40, will have about the same (ACTUAL) amount of SIDEWALL as the 275-35, it might NOT be a bad idea and look too bad.

Driven

Yeah...I'll admit my comments have nothing to do with track knowledge...I don't currently race. But it does have to do with astetic bias and a desire not to create too much "road wandering" with a huge front tire. I've been told the front to rear ratio doesn't have a huge factor in the understeer issue. I don't know...but it was explained to me like this: If your rears are not breaking loose nearly as soon as your fronts...then when you go to a wider front tire you buy yourself that much more lateral traction. So if you start with a 225 and go to a 245 or 255 you now have that much more and the rears aren't part of the equation. Now if you push the car "that" much further...then the ratio becomes involved again due to pushing things to the limit again. Anyway....like I said, I'm not a racer. I just really like the look of a 275 or 285 in the rear and I'm going to be supercharging mine....so no one can argue I'm going too wide. And as far as the fronts go....I wouldn't mind having a 265 up there, but then I not only have higher tire costs...but have a car that will probably follow ruts more than I'd like. I'm either doing a 285 and 245 or 255 combination or a 295 and 255 or 265 combination. Each to his own...if I get into the track scene I'll probably buy a separate set of wheels/tires anyway.