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18" rim fitment issues


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I've seen a few members with 18" rims on there S30's and was wondering if there are any fitment issues?

 

Typically i see people with 17's, i couldn't find to much info about people running 18'' rims.

 

Is it not recommended?

 

i would like to go wide also, ~9F and ~10R with a negative offset. I am planning on flaring the car with the normal baby ZG's.

 

The rims i had my heart set on don't come in 17" anymore, if i want them i have to get 18''.

 

Pictures would help also.

 

Thanks in advance.

 

 

 

 

I THINK I JUST FOUND THE ANSWER TO ONE OF MY QUESTION, 25"-25.5" INCHES IN OVERALL TIRE DIAMETER. CAN'T DELETE POST SO SORRY.

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What fitment issues DID you have before getting it to where it is now?
The real issues were due to the width of the rims I selected and wanting to run without any type of flares. It took shorter 8" springs on the rear in order to raise the lower perch above the tire, rolling the lips all around, and running spacers to get the wheels right where they needed to be. You can see and read a little more on my web site: http://mysite.verizon.net/ress1lhb/barts570z/id19.html.
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25.5" is a pretty tall tire and that will raise the car up. Then you'll want to lower it down really far to get rid of the gap between the tire and fender. This leaves you with little to no suspension travel, and your rockers might be 8 or 9 inches off the ground. If you like this look, then go for it. Newer cars designed for 18" rims have the body built lower in relation to the hub centerline, so they don't have such a high center of gravity when running tall tires, and they're suspension is designed for the larger wheels, so they aren't riding on the bumpstops and don't have the roll center underground like a Z with 18s does. You can fix all of these issues, it's just not easy to do. Search and you'll find info on adjusting roll centers, sectioning struts, bumpsteer, etc. If you don't care about any of that and are just looking for the slammed suspension but still high off the ground look, then just slap them on and cut the springs and you're good to go.

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Jon’s post seems a little condescending towards anyone running 18’s, but maybe I’m a little biased. Here’s another thread regarding someone installing 18’s and a discussion regarding the wisdom of that type of setup: http://forums.hybridz.org/showthread.php?t=117965

 

A larger overall wheel diameter will “raise the car upâ€, but it will decrease the gap between the wheel and the fender by the same amount, so you don’t have to lower it down “really far†to get rid of this gap. I like exactly where my car sits and it has good suspension travel and handles pretty well to boot. I autocrossed my car with this setup and was very happy with the results.

 

... If you don't care about any of that and are just looking for the slammed suspension but still high off the ground look, then just slap them on and cut the springs and you're good to go.

I take issue with Jon’s last sentence, and think he’s really trying to disparage anyone running 18’s. If you don’t like them - don’t run them on your car, but I don’t think my car has the “slammed suspension but still high off the ground look†and I certainly didn’t slap them on or cut my springs.

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Jon’s post seems a little condescending towards anyone running 18’s, but maybe I’m a little biased. Here’s another thread regarding someone installing 18’s and a discussion regarding the wisdom of that type of setup: http://forums.hybridz.org/showthread.php?t=117965

 

A larger overall wheel diameter will “raise the car up”, but it will decrease the gap between the wheel and the fender by the same amount, so you don’t have to lower it down “really far” to get rid of this gap. I like exactly where my car sits and it has good suspension travel and handles pretty well to boot. I autocrossed my car with this setup and was very happy with the results.

 

 

I take issue with Jon’s last sentence, and think he’s really trying to disparage anyone running 18’s. If you don’t like them - don’t run them on your car, but I don’t think my car has the “slammed suspension but still high off the ground look” and I certainly didn’t slap them on or cut my springs.

I was simply pointing out that there are big concessions to make to get them on a Z and it is hard to fix the geometry issues to make them handle as well as smaller rims. The reason people run large rims is for looks. If that's what is important then go for it. There are a lot of modifications people do (even here) for nothing more than appearances.

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Go to this link and check out the Common Snapper Z. This car is running 18 inch wheels, the specs are in the second link at the bottom of the page. http://www.commonsnapper.com/newsite/top/feature/z30.html

http://www.auto-otaku.com/home/2007/11/japanese-pro-to.html

 

I think most go with 17 inch wheels because of the selection and prices of wheel and tire combinations. I would have went with a 18 inch wheel, if I could have found a reasonably price tire 315/30-18( for the rear). Also, you have to take in consideration the tire aspect ratio.. 40 series, 35 series or 30. A 315 /30 -18 is a smaller diameter/ratio than a 315/35-17 tire. If I had deep pockets, I would have put 19 inch wheels with 315/25- 19 on the rear, ....take your Z outside of the box.

Edited by Dudeboy
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A couple of other things to consider-

I am running 18X8's with 245/40 rears and 225/40 fronts. This is for street use. I kept my 15X8 1/2's for autoX if I start up again. I run 225/45's for the autoX. The rotating weight is much higher with the 18's. But I do like the look for the street, and they do fill up my fender wells pretty well. They do raise the ride height some, but this may not be a bad thing for the street. With the Tokico springs and the 18's, the rocker height is 7 1/2" behind the front wheel, which is about 3/4 to 1 inch higher than it would be with 195/60-14's (stock). This also raises my f-body LS oil pan about an inch. While the extra clearance is not needed for racing, the 18's give me a much improved speed bump/oil pan ratio.

Also, for what it's worth, I haven't rolled the fender lips, and I run a 1/4" spacer in the front only because my center caps are not deep enough to clear the dust covers.

Mike

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Are you planning on running flares? I don't think you can fit a 9" wide rim on the front without them.

 

Im not going to use flares, I dont really like them. I have a couple sets of Cobra wheels I can fit before deciding for sure. I have seen a couple cars with 17x9 in the front, so I figured there has to be a way to fit an 18x9 in the front. Like you said, offset/tire choice are crucial.

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