I had some gigantic 285/45 18 x 9 OZ racing wheels in the rear coupled with 245/45 18 x 8 OZs in the front.

I basically had these wheels and tires and I needed new tires for the Z (back then I had the OEM 17 inch base wheels on) so i put these on.

Wow, I didn't know how much they sucked until I put the older track edition wheels and tires on the car.

My MPG has increased 3-5, the front steering is so much lighter, the car accels much better, huge overall improvement.

I will never run huge bulky weighty wheels again.

 

It can make a difference. Do you know how much those OZ wheels weigh? (I think that the oversized tires had quite a bit to do with it also)

 

34,000 miles with the OEM 17-inch wheels and love them. When its time for new wheels, my first choice will be light weight 17-inch wheels.

 

thats why i ended up buying nismo (from stock 18"), not nice looking 19" le-37t.
love its look and love its performance and comfy ride. stock 17", 18" are not really attractive (since we see everywhere) but still 18" ray's track wheels are one attractive wheels.

 

Are you serious? I call BS on that first one.

I hate going back to OEM wheels, can't wait till the new stuff comes in.

 

Or run the light as hell Racing Hart's as I plan to do. They look sexy and weigh next to nothing. Not bad for a 19.

 

Funny you say that. I'm buying new wheels but I think I'm going to be sticking with 17's. My car is my daily driver and it's bumpy enough as it is.

 

with tein flex, my car was actually bumpier on stock 18's then 20's. Theres a difference between stiff and bumpy.

On the 20's it feels smoother, but very stiff. 18's is a softer ride, but will bounce me out of my seat.

I miss the turning and throttle response from the 18's, but I would miss the road feedback from low profile tires on 20's.

 

I went from stock 17s to stock 18s and am not impressed with the larger size.
Understeer is increased, cracks and overpass joints now knock inside the car, new interior buzzing, high speed road noise is increased (I can hardly hear the 80 MPH whine now) and sustained speeds over 100 have more vibration and seem faster (the old tires felt the same at 110 as they did at 85), the slip light comes on earlier and wont let me get the tail out like it used to.

The 17s feel more supple over uneven surfaces and only communicate useful information, I really don't need to know if the penny I just ran over was heads or tails. Even my buddy who car pools with me and did not know I had changed the wheels commented on the car feeling rougher. Lighter 18s might feel better than the heavier stock 18s but I am now looking for some light weight 17x8 replacements and the right tires to make it all work well.

Chris

 

Quite a few of the factors you mention depend on the tires you are using. That's a bigger influence than 17 vs. 18. I'd say that lightweight 18" and very good tires might make a noticeable difference for you.

 

You are right that these factors can be from tires.
My comparison of tires is apples to apples, both have stock tires, stock sizes, and when I got the 18s they had 600 miles on them so the tire variable is roughly the same. I now have 1800 miles on the 18s and they did not get any better after heating them up.

I think light weight 18s would be better than stock 18s even with the same tires and light 17s would probably be better still with the same tires.

Going to better tires will make any combination better but would great tires on 18s work better than great tires on 17s?

Chris

 

Interesting, and I'm glad you posted this--it'll help with my search. RE: your question, I'm not sure, but probably not a big diff.

 

i'm going to track 18s again on thursday... since i sold my 19s... i know it'll be lighter and maybe more throttle response but gotta love the road feedback from low pros and the LOOK! the Z has such wide and deep fender flares that it needs deep and large wheels. oh well i'll be feeling inadequate till spring when i drop the bomb on you guys! lol we'll see after winter

 

I'm telling you those OZ wheels were gigantic. They came off a custom hotrod. I was having a hard time getting over 22 mpg on the freeway, first tank of gas with the track rims on and I am 24-45. City has improve even more.

I understand these wern't lightweight wheels either were the tires, but there was a huge difference.

Here is a pic of the front & rear






I don't know how much weight I have saved, but it's tangible in just about every category. Steering response, throttle response, understeer not nearly as bad, I really can't say enough.

I love these rays trackwheels. I know they arn't really "bling", but they are well made, lightweight and fit the Z well IMO.

The 3-5 mpg was a tad bit of hyperbole, it's more like 2-3. Still that's 40+ more miles. I've also noticed my fuel guage seems to be operating better lol

The FD Rx had some real lightweight 16s. Think the Zs massive torque would eat those alive tho

 

the track wheels are bling dawg! hehe nah for real though, how many Z's rock track wheels like us? pretty rare even more than the infiniti 19s.

 

I was always wondering how the 05+ G35 19s would look on the Z. I never saw any with them, or even a photochop, so I decided to stick with the track wheels.

I imagine the 19s are fairly light as well

 

Some guys have posted photos of the latest G35 wheels on the Z. They look very good--better than on the G, I think. Weight is approx 19 lb.

Related topic: if you use this guy's rule of thumb (link below) for unsprung weight (ie--wheels and tires, some suspension components)...that there is a 1:15 ratio, that means saving 6 pounds off each wheel/tire is the equivalent of 6lb x 4 x 15 = is equal to 360 pounds. This does not take into account the rotational mass of the wheel/tire combination. Even if it's half of this effect, you will notice the performance difference a little bit.
http://www.jtuned.com/content/templa...=288&zoneid=16