Moe747

I just bought RPF1s at 18x10.5+18,lugs, and hub centric rings. I only have rear camber arms installed at the moment, everything else is stock, but I have a couple questions. I've looked into what tire size is good for these wheels and I've read 265/35 square is a great setup to run for street and a bit of track. Does that sound okay? I plan on lowering my car in the future with springs about an inch so I guess I'll have to roll my front fenders, maybe not the rear.

MicVelo

+18?? That a new size? Enkei spec sheet doesn't list a +18... just wondering.

265/35-18 is way too short. By nearly an inch. Fine for track/AX but not so good for the street. Speedo error, clearance issues, VDC error all possible. Not huge issues that can't be worked around but still too short. I bought a set of wheels that had these mounted (from a Subie or something). Gave 'em away.... unusable on my Z.

225 45% 18 25.97 Stock Reference Size
245 45% 18 26.68 Stock Reference Size

245 40% 18 25.72 Front-Alternate
255 35% 18 25.03
255 40% 18 26.03 Front-Alternate
255 45% 18 27.04
265 35% 18 25.30
265 40% 18 26.35
275 35% 18 25.58
275 40% 18 26.66 Rear-Alternate
285 30% 18 24.73
285 35% 18 25.85
285 40% 18 26.98 Rear-Alternate

I won't give a recommendation on square... I don't do, don't like, don't need a square setup. Way too much understeer for my taste. (FOR MY USE, which isn't on track.) Others will be able to make recs.

Moe747

Sorry I meant +15, so with 255/285 the front tires will clear fine but how about the back? They should clear without fenders rolled if I'm stock height, maybe even 1 inch lowered they still don't need fender roll.

travlee

iTrader: (8)

you will need to roll... i rubbed with 18x9.5 +15 with a 275/40 tire

Moe747

Also how would I run a 255 tire on a 10.5 wheel?

travlee

iTrader: (8)

MicVelo

You can run a 255 on 10.5 wheel. You're still above the 90% wheel width:tire width ratio so the tire will have a modest amount of sidewall angularity to the bead (I won't say stretch because if you're over 90%, it's not really stretching the tire.)

S'far as rubbing, almost anything 275 and above will rub on the rear with >9.5 wide with +15 offsets unless you roll the fender lips. (Ask me how I know this....) That's on a lowered car BTW, not sure about stock height. Might still be close and may take a bigger bump to rub.

No_name

Pokin' with a 10.5 +15 up-front and a 255 on that wheel width isn't something I'd put on my Z (fitment, performance, aesthetics...just another opinion FWIW).

Would consider 265/40 and 285/40's if in your shoes, roll when/where you need to pre/post lower and consider alignment specs/parts every step if the way.

I'm with Mic, square for a 99% street ride...not interested.

dboyzalter

iTrader: (3)

For 10.5 all around go with 275/35/18 front 295/35/18 rears... All your friends will be jealous... You will probably rub and need some camber adjustments...

Moe747

That's what I'm going to go with, 265/40 and 285/40. I'll adjust camber and fenders as needed. I only plan on dropping an inch maybe, we'll see how it looks at stock height and I'll go from their. Again, thanks everyone in this thread for the help.

KRyn

Looking to get a custom set of Forgestar F14s for auto-x Street class (stock springs and OEM front camber) on my 2007 Grand Touring 350z, can anyone offer some insight on the following:

Front - 275/35/18 18x9 +23
Rear - 275/40/18 18x10 +23

My initial research leads me to believe that this setup shouldn't be an issue.

TIA

terrasmak

iTrader: (8)

I would do 18x10 +23 front and rear with the tires you mention

KRyn

I would love to but because of SCCA rules I am unable to do so. You are only allowed to change offset by +/- 7 mm, rim diameter by +/- 1" while width must remain the same. I am therefore stuck with 9" fronts and 10" rears.

terrasmak

iTrader: (8)

What tires are you planning to run

KRyn

I am planning to try out the Nexen SUR4G.

Ivanrobles253

travlee

iTrader: (8)

You can do more aggressive than the crap front width/offset and not rub at stock height

MicVelo

Would agree with Trav. You can go 9 or 9.5 up front down to around +22 without rubbing on OE suspension. (Or lower depending on your car but +22 def works fine).

Tires that will NOT rub 245/40-18F & 275/40-18R.

But bottom line, +32 works but is a little larger than OE, barely noticeable, if at all from stock. Just depends on the look and track you're seeking.

Ivanrobles253

travlee

iTrader: (8)

Maybe he is going for dragster look??