HockeyZ39

I currently have 225/45/18 tires up front and 255/45/18 in the rear. I notice that the rears seem to have quite a bit more wall height. I assume this is due to the larger tire being squished more than stock size. I see alot of charts that give the diameter or wall height of tires but none of this accounts for the "squish" im assuming.

My question is will doing 255/40/18 in the rear (while keeping the 45 height up front) make the wall heights seems more even? Or is that to drastic? I would just like the wall hieghts to look even and I have a much easier time finding deals on 255's

TIA!

terrasmak

iTrader: (8)

Have you figured out the electronics in our cars require the difference in tire height from front to rear? I would figure that in 3213 posts you may have read that by now somewhere on the site!

HockeyZ39

I am fully aware of the electronics and what they require, I am also fully aware there is quite a bit of play room. People putting 275/35/18's and having no electronic issues. Have you not read that in your 9,000 posts? My question has nothing at all to do with the electronics feel free to re-read it.

So snide remarks aside my question remains..... Would a 40 height in the rear visually appear to be more uniform with the 45's in the front. This is a question on the visual appears not electronical repercussions. When I had 245's the tire wall disparity was not as great.

EDIT: Also its been over 2 years since I opened this site up, so give me a break.

JPsZ

iTrader: (62)

The actual sidewall height, which is the middle number (45) is actually a percentage of your tires width if i recall correctly. So yes I think going with a 40 will help.

terrasmak

iTrader: (8)

Most of them also have a 255/35-18 front, yes the sizing is off from stock, but the computer see's the correct ratio between front and rear.

Changing away from the proper stagger does effect VDC/TCS/ABS and the handling. Some people don't care, ooks are more important to them.

Spike100

Hi HockeyZ39,

I believe, reading your question, you want the sidewall height on your front and rear tires to be about the same. I hope I have that right.

Since the Z runs a smaller overall tire diameter on the front than the rear, the rear tires must have a greater wall height than the fronts if your front and rear wheels are the same diameter.

If you want about the same sidewall height on your front and rear tires, you need to mount front wheels with a diameter that is less than the rear wheels. The following combinations of front and rear wheel sizes provide similar sidewall height on the front and rear tires:

• 17” front wheel/18” rear wheel
• 18” front wheel/19” rear wheel
• 19” front wheel/20” rear wheel

Notice it’s about an inch in wheel diameter that results in about the same sidewall height on your tire.

But, sidewall height isn’t as simple as measuring the sidewall height with a ruler. In fact metric tire sizing uses a calculation (Sidewall Aspect Ratio) to determine the actual sidewall height as it relates to the tire’s section width. That is what terrasmak means when he mentions that the tires’ series (e.g., 35, 40, 45, etc.) must be related to the tire’s width and the wheel size to be meaningful.

Something else… If you do go with the same diameter tire front and rear (no matter what diameter wheel, but the same all around), you will likely have a setup that fills the front wheel well nicely, but looks weird and ugly (too much gap) in the rear wheel well.

I do not want to alienate you answering your question (life is way too short to make enemies of people you do not even know), but I respectfully suggest that you are on the wrong path attempting to have the same sidewall height on front and rear tires if you have the same diameter wheels on all four corners.

If you do want similar sidewall heights on the front and rear tires, you should mount wheels with about an inch less diameter on the front, and then choose the Sidewall Aspect Ratio that best matches your requirements. That provides a much better solution (esthetically and with better function matching the car's electronics that expect the correct tire diameters).

--Spike

davidv

iTrader: (2)

255/45/18 is taller than 255/40/18. That's a fact. If it "seems more even" to you I don't know.

Spike100

^^ Uhhmm… David… I think you missed the question.

HockeyZ39 is very aware that:
His question is if he should attempt matching sidewall height front (225/45-18”) to rear by swapping his taller 255/45-18” tires for shorter 255/40-18” tires.

I continue telling you that when you become confused, as is happening now, you must increase the oxygen pressure on your ventilator, and concentrate on deeper inhales and exhales… but you do not listen to me.

--Spike