phrozen209

Well, my tires are in since last Thursday, but the rims are still on there marry way!!! I hope I can get them on before Christmas...
Here's da pics...

RUBBER:



RIMS:

CanyonCarver

Nice rims....... 5 narrow spokes ....... the only way to go.

I did some math the other day to determine the size of tire I want to fit to my 18 X 8 wheels. In case anybody is interested.......

225/50 - 16 = 24.858" diameter stock
225/40 - 18 = 25.086" diameter will raise car .114"
235/40 - 18 = 24.401" diameter will lower car .228"
245/40 - 18 = 25.716" diameter will raise car .429"
245/35 - 18 = 24.751" diameter will lower car by .053, best for matching stock diameter.

255/40 - 17 = 25.031" diameter raises car .086" from above stock.
275/35 - 18 = 25.578" " raises car .360" "

I think I'm going for the 235/40-18's if I can find them.


No mo math ho here.....

Copper727

Hahaaha.....hey, thanks for doing the math for us, CanyonCarver! You know how much we all hate math! We'll just take your word for it that you didn't make any mathematical errors...

91zxtt

What do 255/40/17's do in the front?
What do 275/35/18's do in the rear?

CanyonCarver

255/40 - 17 = 25.031" diameter raises car .086" from above stock.
275/35 - 18 = 25.578" " raises car .360" "

no mo math ho........


width x a/r (.40 or .35 or ?) x 2 x .03937 + wheel dia.

91zxtt

Cool, thanks.


Rizz....this equation may be worthy of a sticky.

Copper727

Again, great formula! You even put into consideration the conversion rate from Metric into Standard in your equation! Awesome!!

Hahaaha....you did all that great math, but then you forget to round UP in a few of your figures! :doh: No biggie....

CanyonCarver

LOL ....... so you checked my math .......... I didn't. I was expecting to get beat on. Rounding varies by the time of day and the importance of the result.

I was going to go a little farther with the math and figure the circumferential difference which has an impact on your speedo readings and other stuff but the greatest difference was 3.4% which is minimal. Meaning when your speedo says 60 mph your actually going either 57.96 mph or 62.04 mph not including the error that's already built in.

Riz Z Speed

np, done.

WhtFairLadyZ

I m not sure if any of you guys hace ran into this problem or not. But I know last year when I was shoppin for my wheels for my '92 NA, I played hell tryin to find ones that actually fit. Most shops told me that the wheel came in a size too narrow for my tastes or the offset didn't fit my car. The wheels I have now are Enkei RPM2s 18x8" in the front w/ 18x9" in the rear. "Supposedly" these tires should not be able to fit my car. But they do, lesson learned here...do your own research. If you know what u want and you have information in hand (Diameter, tire sizes, offset) you can almost fit anything in the wheels wells. Almost anything. As for tires, I chose Kuhmo 712s 245/40 ZR 18s up front with 265/ 35 ZR 18s in the rear. The tires look mean, but they leave me wanting more grip. Especially when they are cold. But they are great tires to mess around and drift with, they r very predictable tires.

CanyonCarver

Yep, the right size and offset doesn't mean the wheels will clear the calipers. You can't trust the wheel websites. I had my hopes up for a wheel that I found out wouldn't fit when I went to order them.

phrozen209

finally got my rims on the other day:
webpages.charter.net/phrozen209/300zx
the pics were taken just after washing my Z
im thinking about painting the calipers and probably getting slotted and drilled rotors from work(I work at Brake Parts Inc. so I can get them free!). right now their rusty and dont look very well.
any tips on how to paint the calipers? I was reading this article. is this a good way to do it, and what else would i need?

CanyonCarver

First off I looked at your pics and with the close ups I was like uh-oh, maybe I don't want 18's. then I saw the pic from a ways back and then I said, "that's cool". Looks like it needs to be lowered an inch.

If you paint your calipers, sand blast or acid dip them first, then primer them within an hour or so.

If I do anything to my calipers, I will either get them Anodized or powder coated. In my area, I can get colored anodize done for $50, up to 100 pounds. There are multiple color choices and it's more permanant. To me, paint doesn't hold up very well. Just my 2 cents

CanyonCarver

here's some more wheel info for us novices ......

http://www.streetdreams.org/tech.php

Here I go again ....... Damn brain :doh: So I got to looking at the above link and had a coupla realizations. First off, whether, or not, a wheel fits a car is somewhat independent of the wheel offset. Second, a smaller than stock offset wheel is more likely to fit than a larger offset wheel. What I did know is that maintaining your stock outside tire diameter and stock offest is important relative to steering geometry and front suspension loading. read about scrub radius.

http://www.miata.net/garage/offset.htm
http://www.ingallseng.com/terms.htm (towards the bottom)

As stated in the links, going to a smaller wheel offset will move the tire to the outside of the vehicle, closer to the edge of the fender. less tendency for wider tires to rub on the inside, and a wider "look" with a narrower wheel. ie: 8" wide wheel with 20mm offset, versus stock 45mm, will look like 10" (approx) wide wheel @ stock offset, and no interior rubbing.

So now, If I can find out what effect changing the scrub radius has on a Z.

Here's a good right up on a Z project. Down a ways they talk about wheel fitment / scrub radius. you can read about a specific design of wheel that goes on our cars. It's called "super-face style wheel".

http://www.sportcompactcarweb.com/pr...scc_proj300zx/

This whole issue came to mind because the wheels that I'm going to buy come in 20mm & 40mm offset. I've decided to stick with the 40mm offset because of the steering geometry considerations. I am more into function than looks, but I think I'll add some 1/2" spacers and longer studs to the rears for the look and wider track.

Oh well....... no more rambling today....... the adult kids are finally awake on xmas day.

91zxtt

Here's some more wheel & tire info.

http://www.chris-longhurst.com/carbi...yre_bible.html

Good info about speedometer error with different tire sizes.