drewb612

iTrader: (17)

Looking for some new tires, I know this might be a bit of a stretch but will this be acceptable for street use? If not what is the next size down, thanks!

THe Emperor

iTrader: (4)

It will mainly depend on the tire since each brand tire runs alittle differnent in width. I know for a 8'' rim 255 is the widest you can go so I'm sure you could pull off a 265 on a 8.5'' but it's a good chance the tire will buldge/balloon on the side and look nasty. I'd go with the 255/40/18.

Spike100

265/40-18” is a little too wide for an18x8.5” wheel. You can mount this tire on this wheel, but that would violate the tire manufacturer’s specification. A good tire shop may refuse doing this since this tire size requires a wheel that is at least 9” wide. And, this tire on an 8.5” wide wheel will not look right since the sidewall will bulge.

The widest tire you can use on an 8.5” wide wheel is 255. But a 255 in 255/40-18” is a little short, and a 255/45-18” is a little tall for the Z. Also, 255 is an orphan size (hard to find in the correct aspect ratio for the Z).

Your best choice is a 245/45-18 tire for the rear 18x8.5’ OEM wheel. But I would bet that is not the answer you wanted to hear.

--Spike

PDX_Racer

iTrader: (2)

I run 275/40R17s as street tires. They are *NOT* too wide for the 18x8.5s.

Comparing the 18x8 and 18x8.5s with other cars' 18x8, I'm able to lay down all 285 of my DOT-R autocross tires -- front AND rear.

davidv

iTrader: (2)

The wheel is 215.9 mm wide.
Tire tread is 265 mm. Don't like it.

PDX_Racer

iTrader: (2)

I guess I'm going to lose since everyone wants to quote "recommendations" instead of listening to at least one person who has been running 275s on the rears on the street for the past 3+ years (and I'm not the only one who has been running 275s on the stock 18x8.5s with *no problems* since 2003).

(Oh and to stir the pot some more, my last track day, I ran 275/35R18s on all four wheels -- 18x8 and 18x8.5. Plenty of grip, crisp handling, and very even tire wear across the entire tread surface.)

z-u-later

iTrader: (43)

I've mounted 275/40 tires on four 17x8 stock rims for autocross without any issues.

got556

iTrader: (5)

Different diameters but I run a 255/35/19 on a 19X8.5 wheel....hardly any bulge at all.

DustinZ33

iTrader: (19)

You'd have more choices if you ran 265/35. I'm sure you can run these without a problem on an 8.5" width.

Spike100

I’m not saying it won’t work, but only mentioning that this size goes past the tire manufacturer’s specifications. When you go there, you are on your own as to the risk.

We certainly see success stories using renegade tire/wheel setups (as you describe in your personal experience). It’s just that you need to be aware that these setups may require experimenting with things such as varying psi to get the thread to lie correctly on the roadway. If your setup is a wide tire on a narrow wheel, it may look bulged (but that really comes down to personal preference since some people prefer this look).

Thanks for your input.

--Spike

PDX_Racer

iTrader: (2)

The stock pressures (35PSI) gives me a nice, even wear pattern across the tire.

Spike100

^^ I would like to add another comment to this thread.

I came across an inexpensive buy on a used 275/40 tire that I decided to mount on the rear of my car that at the time had a 18x8” wheel. It was an experiment/test.

I noticed this setup did not lay-down the tire’s tread evenly at 35 psi. My evaluation method was crude (wetting down the tire and rolling forward to examine the tread contact to the pavement). Reducing the pressure fixed the tread-patch contact, but it didn’t keep this tire on the car because my TPMS “protested” the lowered psi, and I felt it looked poorly (too bulged… but of course the appearance is a personal preference).

And… I’m not disputing your statement or experience at all.

I only mention this because there is possibly a difference among different tire manufacturers in results you might experience when mounting sizes that are outside the manufacturer’s recommendation for tire-to-wheel sizing. I would also mention that experiences on the track are different from street-use.

Not arguing… just presenting another view.

--Spike

Spike100

I wonder if the higher sidewall on a 17” wheel might provide more latitude matching tread width to wheel width. That is certainly the case in my experience running tires on off-road vehicles (where the sidewall are very tall and the tread widths are large, but the wheel widths are moderate… but it works great).

Looking at the physical characteristics of a tire, I would guess yes (but it is a guess since I really do not know for sure).

I realize that this is taking the argument to its extreme (the off-road example).

Thanks your comments (which I do consider valuable because they are based in actual experience).

--Spike

Bahraini350Z

I run 275/35/18 for my competetion setup

Spike100

^^ I'm sure it works great. It does look bulged, but who would care how a competition setup looks? It's all about performance... right?

Thanks for your comments and the good pic.

--Spike

lowrider

iTrader: (3)

In a Word YES! I would run no wider though.

Your choice of words is priceless Stretch, no, but 265/40/18s will fit an 8.5" wheel just fine. However, as I said above, that is the widest tire that should be used on that wheel. Anything wider will have tire bulge.

Lou

drewb612

iTrader: (17)

for the record i put on a set of michelin ps2's, 265/40/18 in the rear, they look and hook great, ill have pics eventually

nick123

iTrader: (1)

i have 265 40 18 general tires on the rear of my track wheels....Looks perfect..I wish i went with 275 40 18

z-u-later

iTrader: (43)

^ Yeah, I agree, you could have mounted 275/40 tires easily on rear track rims.

PDX_Racer

iTrader: (2)

+1

Given what I've seen in comparison with the Nissan track wheels with other "8-inch" and "8.5-inch" rims, I'll have to say that they may very well be 8.4 and 8.9 inches. Since there are no "8.4" or "8.9" inch wheels, they may very well be rounded down to the next nearest sizes -- 8.0 and 8.5.

Next time I have tires changed, I'll see if I can get "true" measurements.