Hello… Hey guys, instead of wrecking the thread, could one of you regain focus and help with a legitimate question?

Repeating…
Thanks for any replies (geez you guys)…

--Spike

I provided feedback on this thread and this newb criticizes my posts. Just read his posts and you'll see how newbish and childish they are. My posts are based on "first-hand" experience, not on some recommendation someone is advocating! :icon20:

As far as your concerns, no issues for me mounting 275s on 17x8 rims. I autocrossed this setup hard and did not have any beads come loose or felt any wiggling. Most autocrossers will mount the widest tires possible on the "allowable sized" rims for their class.

^^ Thanks for information.

Your message states that there is “no issues for me mounting 275s on 17x8 rims.”

What about 275/40-18” on 18x8” rims? Any experience here? Is this a safe combination?

--Spike

The recommended wheel widths for a particular tire size is specified to ensure proper geometry of the tire as it was intentionally designed for. The sidewall was designed to serve a purpose when operated in specific conditions. When mounted on wheels that are narrower or wider, sidewall loading is effected, as is contact patch of the tread. This can cause an increase of heat and premature tire wear. Lowering the tire pressure, when installed on wheels too wide, can help emulate the tread footprint as if it were on a narrow wheel offering the intended perpendicular sidewall geometry, but reduces the overall load rating, and increase rolling resistance and again cause heating. In short, the tires just won't last as long as if they were installed on the recommended width wheels, but it can be done. JFYI, I am an engineer for a very popular tire manufacturer, and I too just ordered some 275's for my stocker 8.5's in the rear, fully aware of the consequences. Good luck

:icon22: You are lame-he has the fastest b(?)-stock car, won at the nationals (or came in 2nd cant remember), do you think auto-x'ing sand spending $$$$ on hoosiers is CHEAP? He IS one of the top auto crossers:icon18: Stop assuming things and learn to admit you are wrong. Experience > some "tire expert" anyday! The truth is tire widths vary from manufacturer's, one company's 275 can be as wide as another's 285, so recemmendations are just that, again not the end all, be all for sizing. In the end, put on what you feel comfortable with. I HATE stretched tires, but even extreme 225 on 10" rims dont fail as much as we would like to believe just like a 265 on a 8" rim on stock Z rims wont be a problem. You really are lame for not knowing diff classes have diff rules and assuming my friend is cheap-AND you claim you auto-x? And you dont know this?

BTW-stop being a prick to ZULATER-nobody cares how fast your car is in this thread, Id rape you in reverse but thats not the point here is it?

LMAO-this guy is "educating" us on tire sizing and he is buying four 8.5" wide wheels (another thread) for his 07'! LOL-get some real sizes worth upgrading to:icon17:

To try to answer the OP's questions to the best of my novice ability.

I ran 255/40/17's on stock 8in front 8.5in rear last autox season. The fronts were a bit bulgey but not bad. However, I would probably not run much larger than a 255. 265 wouldnt look TOO bad on an 8.5 but would be a bit of a bulged look. As far as the safety issues? no more saftey issues than these people running really stretched tires. There are a good amount of people that have run 275's on the stock front 8in rim without any trouble, however I wasnt that ambitious.

Take it for what its worth, its not ideal to run over the "recommended" sizing on a wheel, but its not going to make your car implode and kill any woman and child when you drive by them.

Need to change your panties after that post bertie? Without question, I am 100% correct in stating the a 275 is NOT THE BEST SIZE FOR A 8" WIDE WHEEL! I never said anymore than that.....

I was just giving him crap on buying a 06....I could care less what your slow 350 could do....126 trap? Stock cars do that nowadays.....lol. If I wanted a fast car, I'd do it...pointless.

EDIT: and I'll happily stick to my 18x8.5 ET24 Forged BBS RE's that I got for $660, instead of the retail of $3K. Pretty pointless to buy the best quality wheel made for less than Rotas huh?

And fyi, what probably ended up happening in that "champion" autrocrossers case was that the class rules limited the car to no wider than stock sizes. And in that case, putting a wider tire would be beneficial over the stock 245's. With that said, I am still correct in stating that a wider than 8" wheel would make that same 275 tire perform better. Does that make sense to you or did your turbo blow out your vision? ;)

Thanks for the response. Good answer to my question, and I appreciate this.

EDIT: But then again, I would choose the right tire width for the wheels I have on my car. Not willing to mess with guessing about fiddling with tire pressures hoping to match incorrect sizes… but that doesn’t mean you’re wrong using the approach you suggest.

--Spike

I just want to put my 2 pennies in here, remember AutoX is also run at low speeds, typically less than 70mph for a split second and the rest is between 20mph and 55mph. These setups that autocrosses use are typically no daily drivin on and the tires (unlike most street tires) have an extremely stiff sidewall.
Just cause it works for autocross , doesnt mean its fine for the street.

Newb, that's with your Yaris, right? Grow up . . . learn to respect other forum members on this site, especially the ones who have more experience than you on the 350Z. People will disagree on just about everything on here, and you need to respect other people's opinions.

:icon18:

Actually a lot of top autox people do run oversized tires on smaller wheels. #1 reason is if they wish to keep the car in STOCK class, they must keep the wheel size the same as stock but they can put as big of a tire as they can. Seems to me you don't know as much as you think you do.

I love teh interweb bullies :clap:

nerds.. we call them nerds. haha.

wide tires + skinny rims = homer simpson oversized chocolate donuts

+1...I've autoX'd a SCCA B-Stock 350Z on 285 Kumho V710s - it was a very competitive car at Nationals. (with the owner driving :rolleyes: )

You brought a thread back from the dead to make yourself look a tool?

Read what I posted 5 WEEKS ago...and like 4 posts up from yours. :icon22:

Actually no, I brought it back because I was trying to search for something helpful and found this.

Seems to me your the only one here a tool noob.

Great story, now STFU. Did you not READ my post? It says *exactly* what you said....so welcome to being a "Noob" too douche. :icon14:

Is it safe to use 275/40 on 8.5" 18's?
Does somebody use this setup not only for AutoX but for Dayly driving also?