It seems like it would make more sense to use a 35 height. The radius of the wheel changes by 1/2 inch. The stock tire height is 55. A 20 mm reduction in tire height makes up for the 1/2 inch gain in radius. Although, it would actually be a slight drop since 20 millimeter = 0.7874016 inch

BF Goodrich g-Force T/A KDW
Size: 255/35ZR18 94Y

 

Looks super, Ben!!

 

I personally like a bigger rim and tire. I went with a 295/35 in rear and 275/35 in front. But I must say yours looks awesome with the 18's. Hurry up and drop that FWD though... it's driving me crazy. :bang: I want to see the complete package. Be sure to post pics when it's dropped.

 

I was looking at a 295/45/18 for the rear. Must have had the offset wrong it stuck out beyond the wheel well really bad. Looked really tacky to me

 

Where did you order the rims and tires from, I am interested!!

 

Got them locally at Discount TIre. I was shocked the Smoothie's were less expensive than Torque Thrust II. (Started to say cheaper but, since none of them are cheap didn't seem to fit)

 

The middle number isn't simply the height of the sidewall in mm. It's the aspect ratio. It's basically a percentage of the width. 35% of 255mm is 89.25 so a 255/35/18 tire has a sidewall that measures about 89.25mm (3.51"). A 255/45/18 is 114.75mm (4.52").

There are other factors you have to take into account so if you actually measured a tire, it might be off a little, but it's close enough for what we're loking at.

The diameter of the stock tire, 235/55/17, measures 27.2" (theoretically).
255/45/18 = 27.0"
255/35/18 = 25.0"
285/40/18 = 27.0"
295/45/18 = 28.5"

You want to stay as close to the stock tire diameter as you can to keep your speedo and odometer as accurate as possible.

 

Part of the reason it stuck out is the 295 tire is 11.6" wide.
The stock 235 tire is only 9.25" wide.

 

Your car looks great man. I am happy with my steeda springs. I was not aware you could have different rubber colors on the pipe as all I have seen before yours were blue. Nice! Love your wheels too and I am not a wheel / tire person at all.

 

You want to stay as close to the stock tire diameter as you can to keep your speedo and odometer as accurate as possible.
[/quote]

Wow Jason All this stuff is way over my old mind. As long as its not flat on one side I am pleased.

 

It's really just math when you get down to it. But don't worry, there are a lot of tire guys out there that don't know what the numbers mean either... even though they think they do.
If there's anyone who doesn't know how to come up with the diameter or what the numbers mean, and would like to, just start a new thread. I, as well as others, would be happy to explain it. (don't want to hijack this thread anymore)

 

Ben I love your rims, but Im puzzled. I went to my local Discount tire store and could not find any rims that looked like that that would fit my 05. I want 18" chrome bullits just like those! I went on line and I dont see them anywhere either. Is Smoothie the brand name?

 

Looks good, where can you park like that though ??? on the sidewalk/lawn

 

runfox, I got Smoothies also and you can find them online at..... http://www.buyboydwheels.com/index.html. That is a Discount Tire Direct web site. I just went to Discount Tire and told them what I wanted and they ordered them.

 

IM going to go with the 20's fill out the car much better, even though the rice or ghetto look aint for me, it sure does look nice.

 

Reading all of the posts above regarding 35 series vs 45 series and width of tire.
I have 285/40 on the rear and 255/45 on the front. Both sizes are 27" in diameter so very close to factory diameter. Speedo did not change at all.
As for the width, I have 285's on the rear on a 18x10 rim with a 7.25" offset which is the same as +45, therefore, same as factory. If you went with an offset different than that the tire would not fit. I went through 3 sets of rims (different offsets) until I got the perfect fit. I didn't go with 295's for 2 reasons.
1. I would have had to adjust the speedo
2. After lowering the car they would have rubbed on the inside of the fender when I hit a bump.

 

Not sure I understand that one. Take a 20" rim and add a 27" diameter tire to it. Without looking it up my guess is 30 series tire. I bet overall height will be the same as an 18" rim with a 27" diameter tire. Therefore it does not fill out the car much better. All you are doing is replacing sidewall with rim. Mind you, they are not for me but the only 20's on the car I have liked so far are the smoothies.

 

Why do you have to get mathamatical on my ****. : ), 20;s are bigger rim so they fill out the wheel well better. Or they just look that way to me i dunno.

 

nother pic

 

The tires fill the wheel well, not the rim. 27" tire on a 20" rim gives you a total of 27" diamter. 27" tire on an 18" rim gives you a total of 27" diamter. Same space taken up. Not getting "mathematical on your ****" just stating the facts.